Poster presented and Poster Award at the 5th Australia-China Conference on Science, Technology and Education and the 5th Australia-China Symposium for Material Science (July 2015)
Visible light driven photocatalytic oxidation of thiols to disulfides using i...Pawan Kumar
The present paper describes the synthesis of graphene oxide immobilized iron phthalocyanine (FePc) for
the photocatalytic oxidation of thiols to disulfides under alkaline free conditions. Iron phthalocyanine
tetrasulfonamide was immobilized on carboxylated graphene oxide supports via covalent attachment.
The loading of FePc on GO nanosheets was confirmed by FTIR, Raman, ICP-AES, UV-Vis and elemental
analyses. The synthesized catalyst was found to be highly efficient for the photo-oxidation of thiols to
disulfides in aqueous medium using molecular oxygen as oxidant under visible light irradiation. The
identification of photo-oxidation products and their quantitative determination was done using GC-MS.
After completion of the reaction, the catalyst was easily recovered by filtration and reused for several
runs without loss in activity and no leaching was observed during the reaction
Organic inorganic hybrid cobalt phthalocyanine/polyaniline as efficient catal...Pawan Kumar
Organic inorganic hybrid catalyst synthesized by doping of cobalt phthalocyanine (CoPc) on polyaniline
support (CoPc/PANI) exhibited higher activity for the oxidation of various alcohols to the corresponding
carbonyl compounds in high to excellent yield using molecular oxygen as oxidant and isobutyraldehyde
as a sacrificial agent. Notably, the synthesized catalyst was found to be truly heterogeneous in nature and
could be easily recovered, recycled for several recycling runs without loss of catalytic activity
Organic inorganic hybrid cobalt phthalocyanine/polyaniline as efficient catal...Pawan Kumar
Organic inorganic hybrid catalyst synthesized by doping of cobalt phthalocyanine (CoPc) on
polyaniline support (CoPc/PANI) exhibited higher activity for the oxidation of various alcohols
to the corresponding carbonyl compounds in high to excellent yield using molecular oxygen as
oxidant and isobutyraldehyde as a sacrificial agent. Notably, the synthesized catalyst was found
to be truly heterogeneous in nature and could be easily recovered, recycled for several recycling
runs without loss of catalytic activity
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used
for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after
24 h irradiation was 9934 mmol g1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a
sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride
145 mmol g1cat under identical conditions. The presence of triethylamine was found to be vital for the
higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for subsequent six runs without significant loss in photo activity
Photo-induced reduction of CO2 using a magnetically separable Ru-CoPc@TiO2@Si...Pawan Kumar
An efficient photo-induced reduction of CO2 using magnetically separable Ru-CoPc@TiO2@SiO2@Fe3O4
as a heterogeneous catalyst in which CoPc and Ru(bpy)2phene complexes were attached to a solid
support via covalent attachment under visible light is described. The as-synthesized catalyst was characterized
by a series of techniques including FTIR, UV-Vis, XRD, SEM, TEM, etc. and subsequently tested for
the photocatalytic reduction of carbon dioxide using triethylamine as a sacrificial donor and water as a
reaction medium. The developed photocatalyst exhibited a significantly higher catalytic activity to give a
methanol yield of 2570.78 μmol per g cat after 48 h.
Iron phthalocyanine tetrasulfonamide was immobilized to carboxylated graphene oxide support via covalent attachment. The loading of FePc on GO nanosheets was confirmed by FTIR, Raman, ICP-AES, UV-Vis and elemental analyses. The synthesized catalyst was found to be highly efficient for the photo-induced oxidation of thiols to disulfides in aqueous medium using molecular oxygen as oxidant under visible light irradiation. The identification of photo-oxidation products and their quantitative determination was done by using GC-MS. After completion of the reaction, the catalyst was easily recovered by filtration and reused for several runs without loss in activity and no leaching was observed during the reaction.
Visible light driven photocatalytic oxidation of thiols to disulfides using i...Pawan Kumar
The present paper describes the synthesis of graphene oxide immobilized iron phthalocyanine (FePc) for
the photocatalytic oxidation of thiols to disulfides under alkaline free conditions. Iron phthalocyanine
tetrasulfonamide was immobilized on carboxylated graphene oxide supports via covalent attachment.
The loading of FePc on GO nanosheets was confirmed by FTIR, Raman, ICP-AES, UV-Vis and elemental
analyses. The synthesized catalyst was found to be highly efficient for the photo-oxidation of thiols to
disulfides in aqueous medium using molecular oxygen as oxidant under visible light irradiation. The
identification of photo-oxidation products and their quantitative determination was done using GC-MS.
After completion of the reaction, the catalyst was easily recovered by filtration and reused for several
runs without loss in activity and no leaching was observed during the reaction
Organic inorganic hybrid cobalt phthalocyanine/polyaniline as efficient catal...Pawan Kumar
Organic inorganic hybrid catalyst synthesized by doping of cobalt phthalocyanine (CoPc) on polyaniline
support (CoPc/PANI) exhibited higher activity for the oxidation of various alcohols to the corresponding
carbonyl compounds in high to excellent yield using molecular oxygen as oxidant and isobutyraldehyde
as a sacrificial agent. Notably, the synthesized catalyst was found to be truly heterogeneous in nature and
could be easily recovered, recycled for several recycling runs without loss of catalytic activity
Organic inorganic hybrid cobalt phthalocyanine/polyaniline as efficient catal...Pawan Kumar
Organic inorganic hybrid catalyst synthesized by doping of cobalt phthalocyanine (CoPc) on
polyaniline support (CoPc/PANI) exhibited higher activity for the oxidation of various alcohols
to the corresponding carbonyl compounds in high to excellent yield using molecular oxygen as
oxidant and isobutyraldehyde as a sacrificial agent. Notably, the synthesized catalyst was found
to be truly heterogeneous in nature and could be easily recovered, recycled for several recycling
runs without loss of catalytic activity
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used
for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after
24 h irradiation was 9934 mmol g1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a
sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride
145 mmol g1cat under identical conditions. The presence of triethylamine was found to be vital for the
higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for subsequent six runs without significant loss in photo activity
Photo-induced reduction of CO2 using a magnetically separable Ru-CoPc@TiO2@Si...Pawan Kumar
An efficient photo-induced reduction of CO2 using magnetically separable Ru-CoPc@TiO2@SiO2@Fe3O4
as a heterogeneous catalyst in which CoPc and Ru(bpy)2phene complexes were attached to a solid
support via covalent attachment under visible light is described. The as-synthesized catalyst was characterized
by a series of techniques including FTIR, UV-Vis, XRD, SEM, TEM, etc. and subsequently tested for
the photocatalytic reduction of carbon dioxide using triethylamine as a sacrificial donor and water as a
reaction medium. The developed photocatalyst exhibited a significantly higher catalytic activity to give a
methanol yield of 2570.78 μmol per g cat after 48 h.
Iron phthalocyanine tetrasulfonamide was immobilized to carboxylated graphene oxide support via covalent attachment. The loading of FePc on GO nanosheets was confirmed by FTIR, Raman, ICP-AES, UV-Vis and elemental analyses. The synthesized catalyst was found to be highly efficient for the photo-induced oxidation of thiols to disulfides in aqueous medium using molecular oxygen as oxidant under visible light irradiation. The identification of photo-oxidation products and their quantitative determination was done by using GC-MS. After completion of the reaction, the catalyst was easily recovered by filtration and reused for several runs without loss in activity and no leaching was observed during the reaction.
Cobalt Phthalocyanine Immobilized on Graphene Oxide: An Efficient Visible-Act...Pawan Kumar
New graphene oxide (GO)-tethered–CoII phthalocyanine
complex [CoPc–GO] was synthesized by a stepwise
procedure and demonstrated to be an efficient, cost-effective
and recyclable photocatalyst for the reduction of carbon
dioxide to produce methanol as the main product. The developed
GO-immobilized CoPc was characterized by X-ray
diffraction (XRD), FTIR, XPS, Raman, diffusion reflection UV/
Vis spectroscopy, inductively coupled plasma atomic emission
spectroscopy (ICP-AES), thermogravimetric analysis
(TGA), Brunauer–Emmett–Teller (BET), scanning electron microscopy
(SEM), and transmission electron microscopy (TEM).
FTIR, XPS, Raman, UV/Vis and ICP-AES along with elemental
analysis data showed that CoII–Pc complex was successfully
grafted on GO. The prepared catalyst was used for the photocatalytic
reduction of carbon dioxide by using water as
a solvent and triethylamine as the sacrificial donor. Methanol
was obtained as the major reaction product along with the
formation of minor amount of CO (0.82 %). It was found that
GO-grafted CoPc exhibited higher photocatalytic activity
than homogeneous CoPc, as well as GO, and showed good
recoverability without significant leaching during the reaction.
Quantitative determination of methanol was done by
GC flame-ionization detector (FID), and verification of product
was done by NMR spectroscopy. The yield of methanol
after 48 h of reaction by using GO–CoPc catalyst in the presence
of sacrificial donor triethylamine was found to be
3781.8881 mmolg1 cat., and the conversion rate was found
to be 78.7893 mmolg1cat.h1. After the photoreduction experiment,
the catalyst was easily recovered by filtration and
reused for the subsequent recycling experiment without significant
change in the catalytic efficiency
Cobalt Phthalocyanine Immobilized on Graphene Oxide: An Efficient Visible-Act...Pawan Kumar
Abstract: New graphene oxide (GO)-tethered–CoII phthalocyanine
complex [CoPc–GO] was synthesized by a stepwise
procedure and demonstrated to be an efficient, cost-effective
and recyclable photocatalyst for the reduction of carbon
dioxide to produce methanol as the main product. The developed
GO-immobilized CoPc was characterized by X-ray
diffraction (XRD), FTIR, XPS, Raman, diffusion reflection UV/
Vis spectroscopy, inductively coupled plasma atomic emission
spectroscopy (ICP-AES), thermogravimetric analysis
(TGA), Brunauer–Emmett–Teller (BET), scanning electron microscopy
(SEM), and transmission electron microscopy (TEM).
FTIR, XPS, Raman, UV/Vis and ICP-AES along with elemental
analysis data showed that CoII–Pc complex was successfully
grafted on GO. The prepared catalyst was used for the photocatalytic
reduction of carbon dioxide by using water as
a solvent and triethylamine as the sacrificial donor. Methanol
was obtained as the major reaction product along with the
formation of minor amount of CO (0.82 %). It was found that
GO-grafted CoPc exhibited higher photocatalytic activity
than homogeneous CoPc, as well as GO, and showed good
recoverability without significant leaching during the reaction.
Quantitative determination of methanol was done by
GC flame-ionization detector (FID), and verification of product
was done by NMR spectroscopy. The yield of methanol
after 48 h of reaction by using GO–CoPc catalyst in the presence
of sacrificial donor triethylamine was found to be
3781.8881 mmolg1 cat., and the conversion rate was found
to be 78.7893 mmolg1cat.h1. After the photoreduction experiment,
the catalyst was easily recovered by filtration and
reused for the subsequent recycling experiment without significant
change in the catalytic efficiency.
Graphene oxide immobilized copper phthalocyanine tetrasulphonamide: the first...Pawan Kumar
The first successful synthesis of DMC directly from methanol and carbon dioxide using a heterogenized
homogeneous graphene oxide immobilized copper phthalocyanine tetrasulphonamide catalyst in the
presence of N,N0-dicyclohexylcarbodiimide (DCC) as a dehydrating agent is described. The presence of a
dehydrating agent was found to be vital and in its absence the yield of DMC was found to be decreased
significantly. Under the optimized reaction conditions, the maximum yield of DMC reaches up to 13.3%.
Although the homogeneous copper phthalocyanine tetrasulphonamide catalyst provided a little higher
yield of DMC (14.2%), the facile recovery and recycling ability of the heterogeneous catalyst make the
developed method more attractive from environmental and economical viewpoints.
Nitrogen-doped graphene-supported copper complex: a novel photocatalyst for C...Pawan Kumar
A copper(II) complex grafted to nitrogen-doped graphene (GrN700–CuC) was synthesized and then
demonstrated as an efficient photocatalyst for CO2 reduction into methanol under visible light irradiation
using a DMF/water mixture. The chemical and microstructural features of GrN700–CuC nanosheets were
studied by FTIR, XPS, XRD and HRTEM analyses. Owing to its truly heterogeneous nature, GrN700–CuC
could be easily recovered after the photocatalytic reaction and showed efficient recyclability for
subsequent runs.
Visible light assisted photocatalytic reduction of CO2 using a graphene oxide...Pawan Kumar
A new heteroleptic ruthenium complex containing 2-thiophenyl benzimidazole ligands was synthesized
using a microwave technique and was immobilized to graphene oxide via covalent attachment. The synthesized
catalyst was used for the photoreduction of carbon dioxide under visible light irradiation without
using a sacrificial agent, which gave 2050 μmol g−1 cat methanol after 24 h of irradiation
Visible light assisted photocatalytic reduction of CO2 using a graphene oxide...Pawan Kumar
A new heteroleptic ruthenium complex containing 2-thiophenyl benzimidazole ligands was synthesized
using a microwave technique and was immobilized to graphene oxide via covalent attachment. The synthesized
catalyst was used for the photoreduction of carbon dioxide under visible light irradiation without
using a sacrificial agent, which gave 2050 μmol g−1 cat methanol after 24 h of irradiation
Biological and Medical Applications of Graphene NanoparticlesAI Publications
Graphene which is one of the latest additions to nanocarbon family has peculiar band structure, extraordinary thermal and electronic conductance and room temperature quantum Hall effect. It is used in for various applications in diverse fields ranging from catalysis to electronics. In addition to being components in electronic devices, GO have been used in nanocomposite materials, polymer composite materials, energy storage, biomedical applications, catalysis and as a surfactant with some overlaps between these fields Graphene oxide is a unique material that can be viewed as a single monomolecular layer of graphite with various oxygen containing functionalities such as epoxide, carbonyl, carboxyl and hydroxyl groups.
Carbon Nitride Grafted Cobalt Complex (Co@npg-C3N4) for Visible LightAssiste...Pawan Kumar
Azide containing bipyridine complex of cobalt was grafted to
the propargylated nanoporous graphitic carbon nitride (npg-C3
N4) via click reaction to obtain heterogenized photocatalyst
which could efficiently provide direct esterification of aldehydes
under visible light irradiation at room temperature. The use of
click reaction as grafting strategy provided covalent attachment
of the cobalt complex to support which not only provided
higher loading but also precluded the leaching. Furthermore,
the presence of carbon nitride support exhibited synergistic
effect to enhance the reaction rate. In addition, the milder basic
nature of nitrogen containing graphitic support provided
efficient ester synthesis without the need for an external base.
The synthesized photocatalyst was found to be quite robust
which could easily be recovered and reused several times
without significantly losing activity.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after 24 h irradiation was 9934 μmol g−1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride 145 μmol g−1cat under identical conditions. The presence of triethylamine was found to be vital for the higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for subsequent six runs without significant loss in photo activity.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used
for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after
24 h irradiation was 9934 mmol g1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a
sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride
145 mmol g1cat under identical conditions. The presence of triethylamine was found to be vital for the
higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for
subsequent six runs without significant loss in photo activity.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used
for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after
24 h irradiation was 9934 mmol g1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a
sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride
145 mmol g1cat under identical conditions. The presence of triethylamine was found to be vital for the
higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for
subsequent six runs without significant loss in photo activity.
Carbon Nitride Grafted Cobalt Complex (Co@npg-C3N4) for Visible LightAssiste...Pawan Kumar
Azide containing bipyridine complex of cobalt was grafted to
the propargylated nanoporous graphitic carbon nitride (npg-C3
N4) via click reaction to obtain heterogenized photocatalyst
which could efficiently provide direct esterification of aldehydes
under visible light irradiation at room temperature. The use of
click reaction as grafting strategy provided covalent attachment
of the cobalt complex to support which not only provided
higher loading but also precluded the leaching. Furthermore,
the presence of carbon nitride support exhibited synergistic
effect to enhance the reaction rate. In addition, the milder basic
nature of nitrogen containing graphitic support provided
efficient ester synthesis without the need for an external base.
The synthesized photocatalyst was found to be quite robust
which could easily be recovered and reused several times
without significantly losing activity.
Abstract: Novel graphene oxide (GO) tethered Co(II) phthalocyanine complex [CoPc–GO] was synthesized via a stepwise procedure and demonstrated to be an efficient, cost effective and recyclable photocatalyst for the reduction of carbon dioxide to produce methanol as the main product. The developed GO-immobilized CoPc was characterized by X-ray diffraction (XRD), FT-IR, XPS, Raman, diffusion reflection UV-Vis spectroscopy, inductively coupled plasma atomic emission spectroscopy (ICP-AES), TGA, BET, SEM and TEM. FT-IR, XPS, Raman, UV-Vis and ICP-AES along with elemental analysis results showed that Co(II) Pc complex was successfully grafted on GO. The prepared catalyst was used for the photocatalytic reduction of carbon dioxide by using water as a solvent and triethylamine as the sacrificial donor. Methanol was obtained as the major reaction product along with the formation of minor amount of CO (0.82 %). It was found that GO-grafted CoPc exhibited higher photocatalytic activity than homogeneous CoPc as well as graphene oxide and showed good recoverability without significant leaching during the reaction. Quantitative determination of methanol was done by GC-FID and confirmation of product was done by NMR. The yield of methanol after 48 hours of reaction by using GO-CoPc catalyst in the presence of sacrificial donor triethylamine was found to be 3781.8881μmol.g-1-cat and the conversion rate was found to be 78.7893 μmol.g-1cat.h-1. After the photoreduction experiment, the catalyst was easily recovered by filtration and reused for the subsequent recycling experiment without significant change in the catalytic efficiency
A novel Ru/TiO2 hybrid nanocomposite catalyzed photoreduction of CO2 to metha...Pawan Kumar
A novel in situ synthesized Ru(bpy)3/TiO2 hybrid nanocomposite is developed for the photoreduction of
CO2 into methanol under visible light irradiation. The prepared composite was characterized by means of
SEM, TEM, XRD, DT–TGA, XPS, UV–Vis and FT-IR techniques. The photocatalytic activity of the synthesized
hybrid catalyst was tested for the photoreduction of CO2 under visible light using triethylamine
as a sacrificial donor. The methanol yield for the Ru(bpy)3/TiO2 hybrid nanocomposite was found to be
1876 μmol g−1 cat (MeOH 0.024 mol Einstein−1) that was much higher in comparison with the in situ synthesized
TiO2, 828 μmol g−1 cat (MeOH 0.010 mol Einstein−1) and the homogeneous Ru(bpy)3Cl2
complex, 385 μmol g−1 cat (MeOH 0.005 mol Einstein−1).
Photocatalytic reduction of carbon dioxide to methanol using a ruthenium trin...Pawan Kumar
A ruthenium trinuclear polyazine complex was synthesized and subsequently immobilized through
complexation to a graphene oxide support containing phenanthroline ligands (GO-phen). The developed
photocatalyst was used for the photocatalytic reduction of CO2 to methanol, using a 20 watt white cold
LED flood light, in a dimethyl formamide–water mixture containing triethylamine as a reductive
quencher. After 48 h illumination, the yield of methanol was found to be 3977.57 5.60 mmol gcat
1.
The developed photocatalyst exhibited a higher photocatalytic activity than graphene oxide, which
provided a yield of 2201.40 8.76 mmol gcat
1. After the reaction, the catalyst was easily recovered and
reused for four subsequent runs without a significant loss of catalytic activity and no leaching of the
metal/ligand was detected during the reaction
Cobalt Phthalocyanine Immobilized on Graphene Oxide: An Efficient Visible-Act...Pawan Kumar
New graphene oxide (GO)-tethered–CoII phthalocyanine
complex [CoPc–GO] was synthesized by a stepwise
procedure and demonstrated to be an efficient, cost-effective
and recyclable photocatalyst for the reduction of carbon
dioxide to produce methanol as the main product. The developed
GO-immobilized CoPc was characterized by X-ray
diffraction (XRD), FTIR, XPS, Raman, diffusion reflection UV/
Vis spectroscopy, inductively coupled plasma atomic emission
spectroscopy (ICP-AES), thermogravimetric analysis
(TGA), Brunauer–Emmett–Teller (BET), scanning electron microscopy
(SEM), and transmission electron microscopy (TEM).
FTIR, XPS, Raman, UV/Vis and ICP-AES along with elemental
analysis data showed that CoII–Pc complex was successfully
grafted on GO. The prepared catalyst was used for the photocatalytic
reduction of carbon dioxide by using water as
a solvent and triethylamine as the sacrificial donor. Methanol
was obtained as the major reaction product along with the
formation of minor amount of CO (0.82 %). It was found that
GO-grafted CoPc exhibited higher photocatalytic activity
than homogeneous CoPc, as well as GO, and showed good
recoverability without significant leaching during the reaction.
Quantitative determination of methanol was done by
GC flame-ionization detector (FID), and verification of product
was done by NMR spectroscopy. The yield of methanol
after 48 h of reaction by using GO–CoPc catalyst in the presence
of sacrificial donor triethylamine was found to be
3781.8881 mmolg1 cat., and the conversion rate was found
to be 78.7893 mmolg1cat.h1. After the photoreduction experiment,
the catalyst was easily recovered by filtration and
reused for the subsequent recycling experiment without significant
change in the catalytic efficiency
Cobalt Phthalocyanine Immobilized on Graphene Oxide: An Efficient Visible-Act...Pawan Kumar
Abstract: New graphene oxide (GO)-tethered–CoII phthalocyanine
complex [CoPc–GO] was synthesized by a stepwise
procedure and demonstrated to be an efficient, cost-effective
and recyclable photocatalyst for the reduction of carbon
dioxide to produce methanol as the main product. The developed
GO-immobilized CoPc was characterized by X-ray
diffraction (XRD), FTIR, XPS, Raman, diffusion reflection UV/
Vis spectroscopy, inductively coupled plasma atomic emission
spectroscopy (ICP-AES), thermogravimetric analysis
(TGA), Brunauer–Emmett–Teller (BET), scanning electron microscopy
(SEM), and transmission electron microscopy (TEM).
FTIR, XPS, Raman, UV/Vis and ICP-AES along with elemental
analysis data showed that CoII–Pc complex was successfully
grafted on GO. The prepared catalyst was used for the photocatalytic
reduction of carbon dioxide by using water as
a solvent and triethylamine as the sacrificial donor. Methanol
was obtained as the major reaction product along with the
formation of minor amount of CO (0.82 %). It was found that
GO-grafted CoPc exhibited higher photocatalytic activity
than homogeneous CoPc, as well as GO, and showed good
recoverability without significant leaching during the reaction.
Quantitative determination of methanol was done by
GC flame-ionization detector (FID), and verification of product
was done by NMR spectroscopy. The yield of methanol
after 48 h of reaction by using GO–CoPc catalyst in the presence
of sacrificial donor triethylamine was found to be
3781.8881 mmolg1 cat., and the conversion rate was found
to be 78.7893 mmolg1cat.h1. After the photoreduction experiment,
the catalyst was easily recovered by filtration and
reused for the subsequent recycling experiment without significant
change in the catalytic efficiency.
Graphene oxide immobilized copper phthalocyanine tetrasulphonamide: the first...Pawan Kumar
The first successful synthesis of DMC directly from methanol and carbon dioxide using a heterogenized
homogeneous graphene oxide immobilized copper phthalocyanine tetrasulphonamide catalyst in the
presence of N,N0-dicyclohexylcarbodiimide (DCC) as a dehydrating agent is described. The presence of a
dehydrating agent was found to be vital and in its absence the yield of DMC was found to be decreased
significantly. Under the optimized reaction conditions, the maximum yield of DMC reaches up to 13.3%.
Although the homogeneous copper phthalocyanine tetrasulphonamide catalyst provided a little higher
yield of DMC (14.2%), the facile recovery and recycling ability of the heterogeneous catalyst make the
developed method more attractive from environmental and economical viewpoints.
Nitrogen-doped graphene-supported copper complex: a novel photocatalyst for C...Pawan Kumar
A copper(II) complex grafted to nitrogen-doped graphene (GrN700–CuC) was synthesized and then
demonstrated as an efficient photocatalyst for CO2 reduction into methanol under visible light irradiation
using a DMF/water mixture. The chemical and microstructural features of GrN700–CuC nanosheets were
studied by FTIR, XPS, XRD and HRTEM analyses. Owing to its truly heterogeneous nature, GrN700–CuC
could be easily recovered after the photocatalytic reaction and showed efficient recyclability for
subsequent runs.
Visible light assisted photocatalytic reduction of CO2 using a graphene oxide...Pawan Kumar
A new heteroleptic ruthenium complex containing 2-thiophenyl benzimidazole ligands was synthesized
using a microwave technique and was immobilized to graphene oxide via covalent attachment. The synthesized
catalyst was used for the photoreduction of carbon dioxide under visible light irradiation without
using a sacrificial agent, which gave 2050 μmol g−1 cat methanol after 24 h of irradiation
Visible light assisted photocatalytic reduction of CO2 using a graphene oxide...Pawan Kumar
A new heteroleptic ruthenium complex containing 2-thiophenyl benzimidazole ligands was synthesized
using a microwave technique and was immobilized to graphene oxide via covalent attachment. The synthesized
catalyst was used for the photoreduction of carbon dioxide under visible light irradiation without
using a sacrificial agent, which gave 2050 μmol g−1 cat methanol after 24 h of irradiation
Biological and Medical Applications of Graphene NanoparticlesAI Publications
Graphene which is one of the latest additions to nanocarbon family has peculiar band structure, extraordinary thermal and electronic conductance and room temperature quantum Hall effect. It is used in for various applications in diverse fields ranging from catalysis to electronics. In addition to being components in electronic devices, GO have been used in nanocomposite materials, polymer composite materials, energy storage, biomedical applications, catalysis and as a surfactant with some overlaps between these fields Graphene oxide is a unique material that can be viewed as a single monomolecular layer of graphite with various oxygen containing functionalities such as epoxide, carbonyl, carboxyl and hydroxyl groups.
Carbon Nitride Grafted Cobalt Complex (Co@npg-C3N4) for Visible LightAssiste...Pawan Kumar
Azide containing bipyridine complex of cobalt was grafted to
the propargylated nanoporous graphitic carbon nitride (npg-C3
N4) via click reaction to obtain heterogenized photocatalyst
which could efficiently provide direct esterification of aldehydes
under visible light irradiation at room temperature. The use of
click reaction as grafting strategy provided covalent attachment
of the cobalt complex to support which not only provided
higher loading but also precluded the leaching. Furthermore,
the presence of carbon nitride support exhibited synergistic
effect to enhance the reaction rate. In addition, the milder basic
nature of nitrogen containing graphitic support provided
efficient ester synthesis without the need for an external base.
The synthesized photocatalyst was found to be quite robust
which could easily be recovered and reused several times
without significantly losing activity.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after 24 h irradiation was 9934 μmol g−1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride 145 μmol g−1cat under identical conditions. The presence of triethylamine was found to be vital for the higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for subsequent six runs without significant loss in photo activity.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used
for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after
24 h irradiation was 9934 mmol g1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a
sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride
145 mmol g1cat under identical conditions. The presence of triethylamine was found to be vital for the
higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for
subsequent six runs without significant loss in photo activity.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used
for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after
24 h irradiation was 9934 mmol g1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a
sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride
145 mmol g1cat under identical conditions. The presence of triethylamine was found to be vital for the
higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for
subsequent six runs without significant loss in photo activity.
Carbon Nitride Grafted Cobalt Complex (Co@npg-C3N4) for Visible LightAssiste...Pawan Kumar
Azide containing bipyridine complex of cobalt was grafted to
the propargylated nanoporous graphitic carbon nitride (npg-C3
N4) via click reaction to obtain heterogenized photocatalyst
which could efficiently provide direct esterification of aldehydes
under visible light irradiation at room temperature. The use of
click reaction as grafting strategy provided covalent attachment
of the cobalt complex to support which not only provided
higher loading but also precluded the leaching. Furthermore,
the presence of carbon nitride support exhibited synergistic
effect to enhance the reaction rate. In addition, the milder basic
nature of nitrogen containing graphitic support provided
efficient ester synthesis without the need for an external base.
The synthesized photocatalyst was found to be quite robust
which could easily be recovered and reused several times
without significantly losing activity.
Abstract: Novel graphene oxide (GO) tethered Co(II) phthalocyanine complex [CoPc–GO] was synthesized via a stepwise procedure and demonstrated to be an efficient, cost effective and recyclable photocatalyst for the reduction of carbon dioxide to produce methanol as the main product. The developed GO-immobilized CoPc was characterized by X-ray diffraction (XRD), FT-IR, XPS, Raman, diffusion reflection UV-Vis spectroscopy, inductively coupled plasma atomic emission spectroscopy (ICP-AES), TGA, BET, SEM and TEM. FT-IR, XPS, Raman, UV-Vis and ICP-AES along with elemental analysis results showed that Co(II) Pc complex was successfully grafted on GO. The prepared catalyst was used for the photocatalytic reduction of carbon dioxide by using water as a solvent and triethylamine as the sacrificial donor. Methanol was obtained as the major reaction product along with the formation of minor amount of CO (0.82 %). It was found that GO-grafted CoPc exhibited higher photocatalytic activity than homogeneous CoPc as well as graphene oxide and showed good recoverability without significant leaching during the reaction. Quantitative determination of methanol was done by GC-FID and confirmation of product was done by NMR. The yield of methanol after 48 hours of reaction by using GO-CoPc catalyst in the presence of sacrificial donor triethylamine was found to be 3781.8881μmol.g-1-cat and the conversion rate was found to be 78.7893 μmol.g-1cat.h-1. After the photoreduction experiment, the catalyst was easily recovered by filtration and reused for the subsequent recycling experiment without significant change in the catalytic efficiency
A novel Ru/TiO2 hybrid nanocomposite catalyzed photoreduction of CO2 to metha...Pawan Kumar
A novel in situ synthesized Ru(bpy)3/TiO2 hybrid nanocomposite is developed for the photoreduction of
CO2 into methanol under visible light irradiation. The prepared composite was characterized by means of
SEM, TEM, XRD, DT–TGA, XPS, UV–Vis and FT-IR techniques. The photocatalytic activity of the synthesized
hybrid catalyst was tested for the photoreduction of CO2 under visible light using triethylamine
as a sacrificial donor. The methanol yield for the Ru(bpy)3/TiO2 hybrid nanocomposite was found to be
1876 μmol g−1 cat (MeOH 0.024 mol Einstein−1) that was much higher in comparison with the in situ synthesized
TiO2, 828 μmol g−1 cat (MeOH 0.010 mol Einstein−1) and the homogeneous Ru(bpy)3Cl2
complex, 385 μmol g−1 cat (MeOH 0.005 mol Einstein−1).
Photocatalytic reduction of carbon dioxide to methanol using a ruthenium trin...Pawan Kumar
A ruthenium trinuclear polyazine complex was synthesized and subsequently immobilized through
complexation to a graphene oxide support containing phenanthroline ligands (GO-phen). The developed
photocatalyst was used for the photocatalytic reduction of CO2 to methanol, using a 20 watt white cold
LED flood light, in a dimethyl formamide–water mixture containing triethylamine as a reductive
quencher. After 48 h illumination, the yield of methanol was found to be 3977.57 5.60 mmol gcat
1.
The developed photocatalyst exhibited a higher photocatalytic activity than graphene oxide, which
provided a yield of 2201.40 8.76 mmol gcat
1. After the reaction, the catalyst was easily recovered and
reused for four subsequent runs without a significant loss of catalytic activity and no leaching of the
metal/ligand was detected during the reaction
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Perfluorocyclopentenyl (PFCP) Aryl Ether Polymers via Polycondensation of Oct...aaaa zzzz
ABSTRACT: A unique class of aromatic ether polymers
containing perfluorocyclopentenyl (PFCP) enchainment was
prepared from the simple step growth polycondensation of
commercial bisphenols and octafluorocyclopentene (OFCP)
in the presence of triethylamine. Model studies indicate that
the second addition/elimination on OFCP is fast and poly-
condensation results in linear homopolymers and copolymers
without side products. The synthesis of bis(heptafluoro-
cyclopentenyl) aryl ether monomers and their condensation
with bisphenols further led to PFCP copolymers with alternating structures. This new class of semifluorinated polymers exhibit surprisingly high crystallinity in some cases and excellent thermal stability.
Perfluorocyclopentenyl (PFCP) Aryl Ether Polymers via Polycondensation of Oct...Babloo Sharma, Ph.D.
A unique class of aromatic ether polymers
containing perfluorocyclopentenyl (PFCP) enchainment was
prepared from the simple step growth polycondensation of
commercial bisphenols and octafluorocyclopentene (OFCP)
in the presence of triethylamine. Model studies indicate that
the second addition/elimination on OFCP is fast and poly-
condensation results in linear homopolymers and copolymers
without side products. The synthesis of bis(heptafluoro-
cyclopentenyl) aryl ether monomers and their condensation
with bisphenols further led to PFCP copolymers with alternating structures. This new class of semifluorinated polymers exhibit surprisingly high crystallinity in some cases and excellent thermal stability.
Photo-induced reduction of CO2 using a magnetically separable Ru-CoPc@TiO2@Si...Pawan Kumar
An efficient photo-induced reduction of CO2 using magnetically separable Ru-CoPc@TiO2@SiO2@Fe3O4
as a heterogeneous catalyst in which CoPc and Ru(bpy)2phene complexes were attached to a solid
support via covalent attachment under visible light is described. The as-synthesized catalyst was characterized
by a series of techniques including FTIR, UV-Vis, XRD, SEM, TEM, etc. and subsequently tested for
the photocatalytic reduction of carbon dioxide using triethylamine as a sacrificial donor and water as a
reaction medium. The developed photocatalyst exhibited a significantly higher catalytic activity to give a
methanol yield of 2570.78 μmol per g cat after 48 h.
A graphene/hemin hybrid material as an efficient green catalyst for stereosel...Pawan Kumar
A hemin/graphene composite, prepared by mixing an aqueous solution of graphene oxide (GO) with hemin
and sonicating the suspension for 5 h at room temperature, was investigated for olefination of aldehydes
using ethyl diazoacetate in the presence of triphenylphosphine. Efficient olefination of aromatic
aldehydes with high (E)-selectivity was obtained, revealing that rGO/hemin is a promising heterogeneous
catalyst for the olefination reaction. The as-synthesized catalyst could easily be recovered from the
reaction mixture and was subsequently used for several runs without any significantly loss in activity and
selectivity.
Removal of Coke during Steam Reforming of Ethanol over La-CoOx Catalystinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
A [Fe(bpy)3]2+ grafted graphitic carbon nitride hybrid for visible light assi...Pawan Kumar
The present paper describes the use of a readily synthesized, environmentally benign, reusable and nontoxic
iron based nanocomposite i.e iron(II) bipyridine grafted to graphitic carbon nitride (Fe(bpy)3/npg-
C3N4) as a photocatalyst, molecular oxygen as an oxidant and a household white LED as a light emitting
source for the oxidative coupling of benzylamines under mild reaction conditions. The developed heterogenized
homogeneous photocatalyst showed excellent activity with the added benefits of facile recovery
and efficient recycling ability without any significant loss in catalytic activity.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
Toxic effects of heavy metals : Lead and Arsenicsanjana502982
Heavy metals are naturally occuring metallic chemical elements that have relatively high density, and are toxic at even low concentrations. All toxic metals are termed as heavy metals irrespective of their atomic mass and density, eg. arsenic, lead, mercury, cadmium, thallium, chromium, etc.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Poster Presentation and APL Materials Poster Award
1. 800 1000 1200 1400 1600 1800 2000
Intensity(a.u.)
Raman Shift (cm-1
)
Simple and environmental friendly preparation of LiFePO4/C for
lithium ion batteries with effective industrial scale-up potential
Katja Kretschmer1, Shuangqiang Chen1, Yufei Zhao1, Dawei Su1,2, Bing Sun1 and
Guoxiu Wang1*
1Centre for Clean Energy Technology, University of Technology, Sydney, NSW 2007, Australia http://www.cleanenergy.uts.edu.au
2Institute for Superconducting & Electronic Materials, University of Wollongong, Wollongong, NSW 2522, Australia
2.08 nm
2.39 nm
2.50 nm
24h
350 °C 10h
700°C 10h
Iron
precursor
Phosphate
precursor
Lithium
precursor
Carbon
precursor
Pre-sintered
precursor
LiFePO4
interconnected
in 3D carbon
network
• Precursor materials ball milled for 24h in ethanol followed by decomposition at 350
Experimental
Materials preparation
X-ray diffraction (XRD, Siemens D5000), field emission scanning electron microscopy
(SEM, Zeiss Supra 55VP), transmission electron microscopy (HRTEM, FEGTEM 3000
JEOL) and Raman (Renishaw, inVia Raman Microscope) were used to characterize the
prepared materials.
Introduction
Carbon-coated LiFePO4 is prepared in a sequence of simple and easily up scalable
steps via ball milling and solid-state reaction using Starch as carbon source. The
generated morphology appears to be very uniform and the particles are well dispersed.
This uniformity can be attributed to the initiated particle growth during decomposition
and subsequently growth restriction achieved by effective carbon wrapping. The
secondary particle size is between 50-200nm. XRD analysis and electrochemical testing
indicate the significant impact of the applied amount of Starch for the final product,
which so far implies that 10wt% Starch added to the Li/FePO4 precursor is the maximum
content to avoid impurities.
a) b)
c) d)
e) f)
10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
*
**
LiFePO4
2 theta (degree)
Fe2
P
*
15wt%
20wt%
18.5wt%
5wt%
10wt%
8wt%
Results and Discussion
Fig. 1: (a) XRD patterns of LiFePO4/C prepared with 5 – 20 wt% added carbon source (soluble starch); (b) Raman
spectrum of LiFePO4/C prepared with 5 wt% carbon source (soluble starch)
Fig. 1 (a) shows that depending on the amount of added carbon precursor conductivity
enhancing impurities (Fe2P) can be detected. Fig. 1 (b) shows the presence of a rather
amorphous carbon component in the LiFePO4/C composite prepared with 5 wt% carbon
precursor.
Characterization and morphology
Fig. 2: SEM images of LiFePO4/C prepared with 5 – 20 wt% added carbon source (soluble starch);
(a) 5 wt%, (b) 8 wt%, (c) 10 wt%, (d) 15 wt%, (e) 18.5 wt% and (f) 20 wt%
Fig. 2 (a) shows uniformly dispersed grape-like particles of 100-200 nm size wrapped in
a thin 3D carbon network. Fig 2 (b) - (f) shows the influence of the added carbon
precursor on morphology and agglomeration.
a) b)
Conclusion
Carbon-coated LiFePO4 cathode materials are successfully prepared by ball milling and
solid-state reaction using starch as carbon source and only environmental friendly iron,
lithium and phosphate precursors. This method can generate uniformly carbon coated
grape-like nanoparticles, which are very favourable for Li+ transport and tap density of
the final product. Even though Fe2P phases are beneficial for reducing over-potential,
the capacity reduction caused by the high carbon content is disproportionate to justify
adding more than 10 wt% carbon source. Adding 5 wt% carbon source combined with
environmental friendly iron, lithium and phosphate precursor materials appears to be a
suitable and efficient approach to generate large amounts of high performance
LiFePO4/C cathode materials.
Acknowledgment
This original research was proudly supported by Commonwealth of Australia through the
Automotive Australia 2020 Cooperative Research Centre (AutoCRC).
Fig. 3: TEM images of LiFePO4/C prepared with 5 wt% added carbon source (soluble starch) confirming a well
interconnected particle cluster and a uniform distributed carbon coating
Fig. 3 confirms the crystallinity of the obtained material as well as the presence of a
conductivity enhancing, very uniform and thin carbon wrapping of 2 - 3 nm thickness.
The thermal decomposition and carbonization behaviour of starch is very favourable for
the generation of a uniform and thin carbon layer.
Materials characterization
Electrochemical testing
The working electrodes were prepared by mixing 80 % as-prepared LiFePO4/C with 10
% carbon black and 10 % poly(vinyl difluoride) (PVDF, Sigma-Aldrich) in N-Methyl-2-
pyrrolidone (NMP, Sigma-Aldrich). The obtained dispersion was carefully pasted onto
aluminium foil. The working electrodes were assembled to standard CR2032-type coin
cells.
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170
2.0
2.5
3.0
3.5
4.0
4.5
5wt%
8wt%
10wt%
18.5wt%
20wt%
Voltage(V)
Capacity (mAh/g)
10 20 30 40 50 60 70 80 90 100
3.30
3.35
3.40
3.45
3.50
3.55
95.5mV 79.3mV
Electrochemical performance
Fig. 4: (a) Charge-discharge profile of LiFePO4/C prepared with 5 - 20wt% added carbon source (soluble starch); (b)
differential capacity analysis ; (c) cycling performance of LiFePO4/C prepared with 5 wt% added carbon source (soluble
starch) and (d) rate performance of LiFePO4/C prepared with 5 wt% added carbon source (soluble starch)
The reversible capacity of LiFePO4/C prepared with 5 – 10 wt% added carbon source
~148 mAh g-1 whereas the samples prepared with >10 wt% added carbon source only
reach ~128 mAh g-1 at 0.2 C. A reduction in over-potential can be observed
corresponding to the presence of Fe2P impurities., as shown in Fig 4 (a). The differential
capacity analysis in Fig. 4 (b) confirms the observation of the voltage gaps. The samples
with a high Fe2P content show smaller voltage gaps in combination with reduced peak
heights, which is consistent with decreased capacity shown in Fig. 4 (a). The cycling
performance test revealed the high stability of LiFePO4/C for 100 cycles. As shown in
Fig. 4 (c), the material prepared with 5 wt% added carbon source maintained 94 % of the
initial capacity of 140 mAh g-1 after 100 cycles at 1 C. The rate performance test,
displayed in Fig. 4 (d), shows a very good capacity retention and appropriate rate
capability.
0 10 20 30 40 50 60 70 80 90 100
0
20
40
60
80
100
120
140
160
Capacity(mAh/g)
Cycle
5 wt% Starch
1C
0 5 10 15 20 25 30 35 40 45
100
110
120
130
140
150
160
170
Capacity(mAh/g)
Cycle
5 wt% Starch
2 C
1 C
0.5 C
0.2 C
a)
c)
d)
2.0 2.5 3.0 3.5 4.0
-5000
-4000
-3000
-2000
-1000
0
1000
2000
3000
4000
5000
6000
dQ/dV(mAhg-1
V-1
)
Voltage (V)
3.35 3.40 3.45 3.50 3.55
-6000
-4000
-2000
0
2000
4000
6000
dQ/dV(mAhg-1
V-1
)
Voltage (V)
20 wt% 87.4 mV
18.5 wt% 96.6 mV
8 wt% 95.2 mV
5 wt% 103.0 mV
10 wt% 105.4 mV
b)