The document discusses nanocatalysts and their applications in chemical industry. It begins with definitions of catalyst and nanocatalyst. It then discusses different types of nanocatalysts including homogeneous nanocatalysts which are soluble in solvents and heterogeneous nanocatalysts which are insoluble. Methods for preparing both homogeneous and heterogeneous nanocatalysts are described. The document outlines several industrial applications of nanocatalysts such as in biodiesel production, water purification, drug delivery, and fuel cells. It concludes that nanocatalysts have advantages over traditional catalysts like high activity, selectivity, stability, and ease of separation.
It is a nanotechnology question. In which you are able to pick one m.pdfarihantstoneart
It is a nanotechnology question. In which you are able to pick one material for both questions or
one material for question one and another for question two.
Solution
Energy is of great importance in human life because of its benefits as the main resource for
human activity.
The application of nano technology or nano material in the field of energy, which involves
lithium-ion battery, fuel cell, light emitting diode (LED), ultra-capacitor, and solar cell
(including Grätzel cell).
Nanotechnology will bring significant benefits to the energy sector, especially to energy storage
and solar energy. Improved materials efficiency and reduced manufacturing costs are just two of
the real economic benefits that nanotechnology already brings these fields and that’s only the
beginning. Battery storage capacity could be extended, solar cells could be produced cheaper,
and the lifetime of solar cells or batteries for electric cars could be increased, all thanks to
continued development of nanotechnology.
The following nanomaterial technologies will be of particular importance: \"organic and printed
electronics\", \"nano-coatings\", \"nano-composites\", \"nano-fluids\", \"nano-catalysts\",
\"nanocarbons\" and \"nano-electrodes\".
Nanocomposites can be found in nano-structured solar cells and PV (e.g. in polymer-inorganic
PV cells, or as polymer gel electrolytes in dye-sensitized solar cells DSSC or quantum-dot
sensitized solar cells QDSSC) . Nanocomposites are also used for the capture of energy in
silicon-based solar cells, typically in the form of nanowires Nanocomposites can also be found in
antirefl ection coatings and higher solar transmittance coatings on collector glazing (e.g. Ti-Si-O
fi lms via sol-gel-method) In the fi eld of energy storage the advantages of nanocomposites are
needed in thin, fl exible energy storage devices with nanocomposite units, e.g. supercapacitors,
Li-ion batteries and hybrid devices Nanotechnology in the sectors of solar energy and energy
storage Additionally, nanocomposites can be used in the process of semiconductor-assisted
photocatalysis for fuel production in order to obtain solar hydrogen or methanol For example, the
nanocomposites applied here are TiO2 -Gold composite nanoparticles or semiconductor-
semiconductor composites Another fi eld of application lies in the wind energy sector, where
lightweight nanocomposite materials are mainly used for rotor blades.
nanocomposites can be found in nano-structured solar cells and PV (e.g. in polymer-inorganic
PV cells, or as polymer gel electrolytes in dye-sensitized solar cells DSSC or quantum-dot
sensitized solar cells QDSSC) Nanocomposites are also used for the capture of energy in silicon-
based solar cells, typically in the form of nanowires . Nanocomposites can also be found in
antirefl ection coatings and higher solar transmittance coatings on collector glazing (e.g. Ti-Si-O
fi lms via sol-gel-method) . In the fi eld of energy storage the advantages of nanocomposites .
A Review on Nanomaterial Revolution in Oil and Gas Industry for EOR (Enhanced...CrimsonPublishersRDMS
A Review on Nanomaterial Revolution in Oil and Gas Industry for EOR (Enhanced Oil Recovery) Methods by Veluru Jagadeesh Babu* in Crimson Publishers: Peer Reviewed Material Science Journals
It is a nanotechnology question. In which you are able to pick one m.pdfarihantstoneart
It is a nanotechnology question. In which you are able to pick one material for both questions or
one material for question one and another for question two.
Solution
Energy is of great importance in human life because of its benefits as the main resource for
human activity.
The application of nano technology or nano material in the field of energy, which involves
lithium-ion battery, fuel cell, light emitting diode (LED), ultra-capacitor, and solar cell
(including Grätzel cell).
Nanotechnology will bring significant benefits to the energy sector, especially to energy storage
and solar energy. Improved materials efficiency and reduced manufacturing costs are just two of
the real economic benefits that nanotechnology already brings these fields and that’s only the
beginning. Battery storage capacity could be extended, solar cells could be produced cheaper,
and the lifetime of solar cells or batteries for electric cars could be increased, all thanks to
continued development of nanotechnology.
The following nanomaterial technologies will be of particular importance: \"organic and printed
electronics\", \"nano-coatings\", \"nano-composites\", \"nano-fluids\", \"nano-catalysts\",
\"nanocarbons\" and \"nano-electrodes\".
Nanocomposites can be found in nano-structured solar cells and PV (e.g. in polymer-inorganic
PV cells, or as polymer gel electrolytes in dye-sensitized solar cells DSSC or quantum-dot
sensitized solar cells QDSSC) . Nanocomposites are also used for the capture of energy in
silicon-based solar cells, typically in the form of nanowires Nanocomposites can also be found in
antirefl ection coatings and higher solar transmittance coatings on collector glazing (e.g. Ti-Si-O
fi lms via sol-gel-method) In the fi eld of energy storage the advantages of nanocomposites are
needed in thin, fl exible energy storage devices with nanocomposite units, e.g. supercapacitors,
Li-ion batteries and hybrid devices Nanotechnology in the sectors of solar energy and energy
storage Additionally, nanocomposites can be used in the process of semiconductor-assisted
photocatalysis for fuel production in order to obtain solar hydrogen or methanol For example, the
nanocomposites applied here are TiO2 -Gold composite nanoparticles or semiconductor-
semiconductor composites Another fi eld of application lies in the wind energy sector, where
lightweight nanocomposite materials are mainly used for rotor blades.
nanocomposites can be found in nano-structured solar cells and PV (e.g. in polymer-inorganic
PV cells, or as polymer gel electrolytes in dye-sensitized solar cells DSSC or quantum-dot
sensitized solar cells QDSSC) Nanocomposites are also used for the capture of energy in silicon-
based solar cells, typically in the form of nanowires . Nanocomposites can also be found in
antirefl ection coatings and higher solar transmittance coatings on collector glazing (e.g. Ti-Si-O
fi lms via sol-gel-method) . In the fi eld of energy storage the advantages of nanocomposites .
A Review on Nanomaterial Revolution in Oil and Gas Industry for EOR (Enhanced...CrimsonPublishersRDMS
A Review on Nanomaterial Revolution in Oil and Gas Industry for EOR (Enhanced Oil Recovery) Methods by Veluru Jagadeesh Babu* in Crimson Publishers: Peer Reviewed Material Science Journals
Globally, the demand for industrial catalysts is driven by the surging demand for chemicals in various end applications in industries such as personal care products, lubricants, petroleum refinery, pharmaceuticals and foods & beverages. Growing awareness among manufacturers of chemicals and consumers, related to environment and increasing emissions impacting the eco system have led to highly intense competition in the global market for catalysts.
As per research reports, the global industrial catalyst market is estimated at roughly USD 17.5 bn (depicted in Figure 5) as of FY15 and is forecasted to grow at a CAGR of 4% - 5% during FY15 to FY20, on account of rising consumption of chemicals and their applicability. The APAC region remains the major market followed by North America and Europe. In the forecast period, the APAC region is expected to continue to witness strong growth driven by India and China
Different types of methods can be used for the preparation of Magnetic Nanoparticles, their advantages and disadvantages and applications of the materials in various fields are given in the presentation
The threat of global warming is high due to the extensive use of fossil fuels.Using non-renewable resources is a viable solution. Sunlight can be converted in two ways - into electrical energy and into chemical energy. Water splitting and CO2 are two important methods which can be used in solar cells.
Acomprehensively brief description of Nanotechnology/Nanobiotechnology, Nanoparticles and the applications of Nanotechnology/Nanobiotechnology using Nanoparticles.
Globally, the demand for industrial catalysts is driven by the surging demand for chemicals in various end applications in industries such as personal care products, lubricants, petroleum refinery, pharmaceuticals and foods & beverages. Growing awareness among manufacturers of chemicals and consumers, related to environment and increasing emissions impacting the eco system have led to highly intense competition in the global market for catalysts.
As per research reports, the global industrial catalyst market is estimated at roughly USD 17.5 bn (depicted in Figure 5) as of FY15 and is forecasted to grow at a CAGR of 4% - 5% during FY15 to FY20, on account of rising consumption of chemicals and their applicability. The APAC region remains the major market followed by North America and Europe. In the forecast period, the APAC region is expected to continue to witness strong growth driven by India and China
Different types of methods can be used for the preparation of Magnetic Nanoparticles, their advantages and disadvantages and applications of the materials in various fields are given in the presentation
The threat of global warming is high due to the extensive use of fossil fuels.Using non-renewable resources is a viable solution. Sunlight can be converted in two ways - into electrical energy and into chemical energy. Water splitting and CO2 are two important methods which can be used in solar cells.
Acomprehensively brief description of Nanotechnology/Nanobiotechnology, Nanoparticles and the applications of Nanotechnology/Nanobiotechnology using Nanoparticles.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
atmosphere through the stack. The flue gas can be a potential
source for obtaining much needed cooling water for a power
plant. If a power plant could recover and reuse a portion of this
moisture, it could reduce its total cooling water intake
requirement. One of the most practical way to recover water
from flue gas is to use a condensing heat exchanger. The power
plant could also recover latent heat due to condensation as well
as sensible heat due to lowering the flue gas exit temperature.
Additionally, harmful acids released from the stack can be
reduced in a condensing heat exchanger by acid condensation. reduced in a condensing heat exchanger by acid condensation.
Condensation of vapors in flue gas is a complicated
phenomenon since heat and mass transfer of water vapor and
various acids simultaneously occur in the presence of noncondensable
gases such as nitrogen and oxygen. Design of a
condenser depends on the knowledge and understanding of the
heat and mass transfer processes. A computer program for
numerical simulations of water (H2O) and sulfuric acid (H2SO4)
condensation in a flue gas condensing heat exchanger was
developed using MATLAB. Governing equations based on
mass and energy balances for the system were derived to
predict variables such as flue gas exit temperature, cooling
water outlet temperature, mole fraction and condensation rates
of water and sulfuric acid vapors. The equations were solved
using an iterative solution technique with calculations of heat
and mass transfer coefficients and physical properties.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
HEAP SORT ILLUSTRATED WITH HEAPIFY, BUILD HEAP FOR DYNAMIC ARRAYS.
Heap sort is a comparison-based sorting technique based on Binary Heap data structure. It is similar to the selection sort where we first find the minimum element and place the minimum element at the beginning. Repeat the same process for the remaining elements.
2. Introduction
Catalyst :Substance that increases a chemical reaction rate without being
consumed or chemically altered.
Anastas, P.T.; Warner, J. C. Green Chemistry: Theory and Practice, Oxford University
Press: New York, 1998, p.30.
3. Historical Hierarchy
The field of nanocatalysis is not as new as could be expected
from the current nanohype. Actually, its concept is known since
the 1950s when the term nanotechnology was not even known.
3
4. Introduction
4
Nanocatalysis
is a process in which catalysis process use
products of nanotechnology as a catalyst which are referred as
“Nanocatalyst”.
Nanocatalyst
A catalyst composed of nanoparticles.
Smaller than 100 nm in at least one dimension Porous
compounds having pore diameters not bigger than 100 nm.
Catalysis
is the increase in the rate of a chemical reaction due
to the participation of an additional substance called a catalyst.
5.
6. Catalysts
Homogenous
Heterogeneous
Enzymatic
Nano-catalysts have combined
advantages of both the homogeneous
and heterogeneous catalytic systems.
Nano catalytic system allows the rapid,
selective chemical transformations with
excellent product yield coupled with the
ease of catalyst separation and recovery.
Recovery of catalysts from the system
is most important characteristics of any
catalyst before being acceptable for
green chemical manufacturing
processes in industry.
Because of nano size (high surface area)
the contact between reactants and
catalyst increases dramatically (this
phenomenon is close to homogeneous
catalysis).
Insolubility in the reaction solvent
makes the catalyst heterogeneous and
hence can be separated out easily from
the reaction mixture (this phenomenon
is close to heterogeneous catalysis)
7. Catalytic activity of materials - How it is depend on the size of
materials?
Homogenous Catalysts Heterogeneous Catalysts
Nanocatalysts
Merits:
High activity
High chemo-and regio selectivity
Demerits:
Cumbersom product purification
and difficulty in catalyst recovery
Merits:
Excellent stability
Easy accessibility
Easily separable
Demerits:
Inferior catalytic activity
relative to their counterpart
homogeneous and requires
more reaction time
High activity
High selectivity
Excellent stability
Easily separable
Energy efficient
Atom economy
8. HOMOGENEOUS NANOCATALYSTS
A solution or suspension of nanoparticles in
a solvent, i.e., catalyst is in a same phase to
the reactants.
It is a must to consider how to prevent its
aggregation when designing a nano-catalyst
for use in a solution.
Nanoparticles have a special characteristic
to aggregate and will clump together to form
larger particles, if it is not prevented
properly, nanoparticles lose their large
surface area and other benefits.
Catalyst which is in a different phase to the
reactants.
It is always considered as more
environmentally friendly catalysis due to its
high recoverability.
The heterogeneous catalyst may be usually a
solid or immobilized on a solid inert matrix.
HETEROGENEOUS NANOCATALYSTS
10. 1. Chemical Reduction Method:
Reduction of transition metal salt in solution to form the
nanoparticales.
2.Thermal, Photochemical and Sonochemical Reduction
Method:
Decomposition of the precursor organometallic salt to the
zerovalent form.
Homogeneous Nanocatalyst
Preparation Method
11. 3. Ligand Displacement Method:
Displacement of ligand in the organometallic complex.
4. Condensation of Metal Vapor Method:
Evaporation of transition metal vapors at reduced pressure
and subsequent co- condensation of these metals at low
temperature with organic vapors.
5. Electrochemical Reduction Method:
Precursor metal ions are reduced at the cathode using anode
as the metal source
Homogeneous Nanocatalyst
Preparation Method
13. Heterogeneous Nanocatalyst
Preparation Method
Adsorption Method:
Heterogeneous metal nanocatalyst are
prepared by adsorption of nanoparticles onto support which
involves functionalization of support to adsorb nanoparticle on
to them.
Example:
Synthesis,
activity of oleic
characterization and catalytic
acid-coated TiO2 nanoparticles
carrying MoO2 (acac)2
(Bis(acetylacetonato)dioxomolybdenum(VI))
in the oxidation of olefins and sulfides using economical
peroxides.
17. Types of Nanocatalyst involved in
Nanocatalysis
Nanoparticle Catalysts
(Au/TiO2, Pt-Pd-Rh Three way catalyst)
Nanoporous Catalysts
Microporous (4–14 Angstrom)- Mesoporous (15 –
250 Angstrom)
Nanocrystalline Catalysts
(Nanocrystalline CeO2-x, TiO2)
Nanocomposite Catalysts
Supramolecular Catalysts
18.
19. Catalytic Activity of Nanocatalyst
Catalytic activity of Nanocatalyst depends on
following parameters.
1. Geometry
2. Composition
3. Oxidation state
4. Physical environment
5. Chemical environment
20. Principle of Catalysis
1.Increases the rate of chemical reaction by reducing the
required activation energy and alter the required reaction
temperature.
2.Catalyst provide a site for the reactants to be activated and
interacted together while leaving the catalyst surface
unchanged after the reaction.
21. Principle of Catalysis
3. Normally catalyst surface must have the high
active energy, right structure, and enough spaces.
22. Industrial Applications
1. (Nano NiO/γ-Al2O3)
Biomass gasification to produce high syn gas and
biomass pyrolysis for bio-oil
2.Al0.9H0.3PW12O40 (ALUMINUMDODECATUNGSTOPHOSPHATE)
with surface area of 278 m2/g
Production of biodiesel from waste cooking oil
3. (Fe and Co) powders 10-50nm
Green Diesel production using Fischer-Tropsch
4. (Mesoporous In2O3, particle size 2-3 nm)
Hydrogen production by steam reforming of ethanol
23. Water Purification
V
.Shashikala et al., Indian Institute of Chemical Technology, Hyderabad; Journal of Molecular Catalysis A: Chemical 268 (2007) 95–100
o The main advantage of Ag supported catalysts prepared by electro-chemical deposition over
that made by conventional impregnation technique is that only small amount is needed and no
pretreatment conditions like reduction are required for deactivation of microorganism in water.
o Thus, silver catalysts prepared by this method are not only efficient but also economical in
restoring hydrogen economy.
o It is also concluded evidently that the Ag supported catalysts arereusable.
o The combined characteristics of Al2O3 and carbon like low acidity, high mechanical strength
and presence of meso pores in carbon coverage in alumina (CCA) are also helpful for
designing highly active AgCCAcatalyst.
A novel electro-chemical deposition method of synthesizing nano-metallic particles of silver over
carbon covered alumina, which is highly efficient in controlling microbes in water.
24. Biodiesel Production
o The catalyst is well used to convert the oil with higher acid value into biodiesel.
o It is porous with particle sizes of 30–100 nm. XRD analysis showed the catalyst has new
crystal KCaF3, which increases catalytic activity and stability.
o The high specific surface area and large pore size are favorable for contact between catalyst
and substrates, which effectively improved efficiency of transesterification.
o Production of biodiesel from Chinese tallow seed oil has positive impact on the utilization of
agricultural and forestry products.
The solid base nanocatalyst KF/CaO can be used to convert Chinese tallow seed oil to biodiesel
with yield of more than 96%.
Effect of catalyst usage on biodiesel yield.
(a–e) Catalyst usage 1%, 2%, 3%, 4%, 5%.
L. Wen et al., Huazhong Agricultural University, China; Fuel 89 (2010) 2267–2271
25. Drug Delivery
o The guest molecule loading of CPyNs was conducted with
pyrene as a typical hydrophobic dye and the guest molecule-
releasing test was performed with ibuprofen as a typical
hydrophobic drug.
o CPyNs showed highly microporous compared to zeolite,
resulting in loading guest molecules into CPyNs using phase
separation.
o In addition, the magnetic property of CPyNs provided the
selective separation and targeting.
o CPyNs sustained in vitro drug release properties.
Importantly, smaller size and amine surface modification of
CPyNs provide an improved sustained property.
o Due to their superiorities such as microporous structure,
monodispersity, magnetism, and biocompatibility, it is
believed that the CPyNs open the way to use in fields such
as biomaterials science, including bioimaging and magnetic
induced drug carriers.
W.-K. Oh et al., Seoul National University, Republic of Korea; Biomaterials 31 (2010) 1342–1348
The fabrication of carbonized polypyrrole nanoparticles (CPyNs) with controlled diameters and
their textural properties and investigated the potential capability of CPyNs as imaging probes and
drug carriers based on their porosity, magnetic property and biocompatibility.
TEM image of IMR90 cells incubated with
CPyN-1 at 25 mgmL1 for 24 h. Circles exhibits
the endocytotic CpyN-1 vesicle.
26. Fuel Cell Applications
o It is observed that carrying out the entire process of
Pt/C formation in N2 showed very good control over
Pt particle size whereas the Pt loading is
significantly low.
o When the process of Pt/C formation is carried out in
the presence of O2, the Pt loading is increased up to
36 wt.%. However, the particle size of Pt increases
due to agglomeration at low solution pH.
o As a modification to the polyol process, the
reduction of Pt metal ions at elevated temperature
with N2 purging followed by the further reduction at
room temperature with air showed the best results
with almost 40 wt.% loading and a small particle
size of 2.8 nm.
o From the single cell test, it was found that operating
in ambient O2 at 70 °C can deliver high performance
of more than 0.6V at 1.44Acm−2.
H.-S. Oh et al., Yonsei University, Republic of Korea;Electrochimica Acta 52 (2007) 7278–7285
The studies showed that parameters of Pt colloid prepared by using the polyol process although
the adjustment of pH behaves as a key factor in controlling the nanodimension of the Pt particles,
a severe reduction in the metal loading is observed with increasing solution pH.
HR-TEM images of Pt catalysts synthesized in ethylene
glycol solution with different gas conditions: (a) N2
purging, (b) open to air, (c) O2 purging and (d) N2
purging followed by opening to air. Spt is the specific
active surface area calculated by cyclic voltammogram.
27. Photo Catalytic Activity
o TiO2 is regarded as the most efficient and environmentally benign photocatalyst and has been
most widely used for photodegradation of various.
o TiO2 photocatalysts can also be used to kill bacteria, as has been carried out with E. coli
suspensions.
o The strong oxidizing power of illuminated TiO2 can be used to kill tumor cells in cancer
treatment.
o Upon absorption of photons with energy larger than the band gap of TiO2, electrons are
excited from the valence band to the conduction band, creating electron– hole pairs. These
charge carriers migrate to the surface and react with the chemicals adsorbed on the surface to
decompose these chemicals. This photodecomposition process usually involves one or more
radicals or intermediate species such as OH, O2, H2O2, and O2, which play important roles in
the photocatalytic reaction mechanisms.
o The photocatalytic activity of a semiconductor is largely controlled by:
i. the light absorption properties, e.g., light absorption spectrum and coefficient,
ii. reduction and oxidation rates on the surface by the electron and hole, and
iii. the electron–hole recombination rate.
o Large surface area with constant surface density of adsorbents leads to faster surface
photocatalytic reaction rates. In this sense, the larger the specific surface area, the higher the
photocatalytic activity is. On the other hand, the surface is a defective site, therefore the larger
the surface area, the faster the recombination.
Photocatalysts
28. Photo Catalytic Activity Photocatalysts
The photocatalytic activity in the visible part of the solar spectrum (442 nm) for demonstration of
highly organized mesoporous nanocrystalline titania thin films doped with thiourea.
o High temperature treatment usually improves the crystallinity of
TiO2 nanomaterials, which in return can induce the aggregation
of small nanoparticles and decrease of the surface area.
o The mesoporous TiO2 thin films produced displays
photocatalytic activity in the visible part of the solar spectrum.
o The strategy involves the sequential deposition by EISA of
mesostructured thin films that are doped with thiourea,
producing films with fine control over film thickness and having
a high degree of crystallinity in the anatase form.
o The photocatalytic activity of TiO2 films having different
thickness was demonstrated by monitoring the degradation of
methylene blue (MB).
S.S.Soni et.al, Universite´ du Maine, France; Adv. Mater. 2008, 20, 1493–1498
a) Variation in absorbance spectra of MB in
contact with a TiO2 film coated five times as a
function of visible light irradiation time. b)
Decoloration of MB solution by TiO2 films:
curve A, without TiO2 film; B, thin film; C, 1x
film; D, 3x film; E, 5x film.
29. Photo Catalytic Activity Photovoltaics
o Photovoltaics based on TiO2 nanocrystalline electrodes have been widely studied on dye-
sensitized solar cell (DSSC).
o The mesoporosity and nanocrystallinity of the semiconductor are important not only because
of the large amount of dye that can be adsorbed on the very large surface, but also for two
additional reasons: (a) they allow the semiconductor small particles to become almost totally
depleted upon immersion in the electrolyte (allowing for large photovoltages), and (b) the
proximity of the electrolyte to all particles makes screening of injected electrons, and thus
their transport, possible.
o Ordered mesoporous TiO2 nanocrystalline films showed enhanced solar conversion efficiency
by about 50% compared to traditional films of the same thickness made from randomly
oriented anatase nanocrystals.
o Higher efficiencies of solar cells were achieved with TiO2 nanotube-based electrodes due to
the increase in electron density in nanotube electrodes compared to P25 electrodes.
o Nanoporous electrodes in a core– shell configuration, usually a TiO2 core coated with Al2O3,
MgO, SiO2, ZrO2, or Nb2O5, could improve the performance of dye-sensitized solar cells.
o Doped TiO2 nanomaterials also show a good promise in the application of DSSCs. For the best
N-doped TiO2 electrodes, the photoinduced current due to visible light and at moderate bias
increased around 200 times compared to the behavior of pure TiO2 electrodes.
30. Solid Rocket Propellant
o Replacement of micro-aluminum by nano-aluminum increases the propellant burning rate by
100% regardless of the other parameters considered in this paper.
o These burning rates always show low pressure-exponents in the elevated pressure range.
o These results show that the nano-aluminized propellant burning rate is controlled by the near-
surface ignition and diffusion-limited combustion of nano-aluminum agglomerated to 5 lm in
size, at elevated pressures.
o The increase in nano-aluminum size decreases the burning rate but the opposite effect is
observed with micro-aluminum.
o The burning rate monotonically increases with nano-aluminum content in bimodal aluminized
propellants.
o Nano-sized catalysts increase the burning rate by 5% in nano-aluminized propellants.
K. Jayaraman et al., Indian Institute of Technology - Madras; Combustion and Flame, 156 (2009) 1662–1673
The nano-aluminum particles of 50 nm size are added to composite solid propellants based on
ammonium perchlorate and hydroxyl-terminated poly-butadiene binder that exhibit plateau
burning rate trends.
31. Environmental Protection
o This study includes (i) need of heterogeneous activation of sulfate salts using transition metal
oxides, (ii) nanoscaling of the metal oxide catalysts for high catalytic activity and promising
properties with respect to leaching, and (iii) easy removal and recovery of the catalytic
materials after their applications for water and wastewater treatments.
heterogeneous activation of peroxymono-sulfate (PMS) to generate SRs targeting
o In this study a novel approach of using Fe-Co mixed oxide nanocatalysts for the
the
decomposition of 2,4-dichlorophenol was introduced.
o It was found that this catalyst is the most promising for the efficient and environmentally
friendly activation of PMS.
Sulfate radical-based advanced oxidation technologies (SRAOTs) are attracting considerable
attention due to the high oxidizing ability of SRs to degrade organic pollutants in aqueous
environments.
Q. Yang et al., University of Cincinnati, United States; Applied Catalysis B: Environmental 88 (2009) 462–469
32. Thin Film Solar Cell
Many nano-structured materials are now being investigated for their potential applications in
photovoltaic, electro-optical, micromechanical and sensor devices. Advantage of the benefits is
also to make inexpensive and efficient solar cells on a large scale. Nanostructured layers in thin
film solar cells offer three important advantages.
(i) Due to multiple reflections, the effective optical path for absorption is much larger than the
actual film thickness.
(ii) Light generated electrons and holes need to travel over a much shorter path and thus
recombination losses are greatly reduced. As a result, the absorber layer thickness in
nanostructured solar cells can be as thin as 150 nm instead of several micrometers in the
traditional thin film solar cells .
(iii) The energy band gap of various layers can be tailored to the desired design value by varying
the size of nano-particles. This allows for more design flexibility in the absorber and window
layers in the solar cell. In particular nano-structured CdS, CdTe and TiO2 are of interest as
window and absorber layers in thin film solar cells.
33. The self-assembly process to fabricate a variety of nano-structured films including CdTe and CdS
on ITO coated glass substrates. In addition nano-porous CdS and TiO2 films were fabricated on a
plastic substrate with a view to making devices on a lightweight, flexible substrate.
o The results indicated a blue shift in the absorption with an
effective band gap of 2.8 eV. This opens the possibility of using
nanocrystalline n-type CdTe as a window layer in an n-CdTe/p-
CdTe homo junction solar cell.
o Nano-crystalline CdS films on ITO coated glass substrates
exhibited particle sizes of 15 nm and an effective band gap of
2.98 eV as compared to the 2.4 eV value for the band gap of
bulk CdS. This makes nano-crystalline CdS a better window
material in an n-CdS/p-CdTe hetero junction solar cell.
o Porous CdS and porous TiO2 films were deposited on plastic
substrates by a self assembly method. Typical pore sizes were 80
and 70 nm, respectively. These can be used in nano-structured
solar cell configuration where the pores are filled with a p-type
absorber material.
o Due to the nanostructured character of the absorber, the
transport path for the light generated electrons in the absorber is
reduced. At the same time, the optical path for photon
absorption is increased due to multiple reflections.
R.S. Singh et al., University of Kentucky, USA; Solar Energy Materials & Solar Cells 82 (2004) 315–330
Thin Film Solar Cell
34. Nano Toxicology
The toxicity of starch-coated silver nanoparticles was studied using normal human lung fibroblast
cells (IMR-90) and human glioblastoma cells (U251).
P.V
.AshaRani et.al., National University of Singapore, Singapore; ACS Nano 3(2): 279-290, 2009
o The toxicity was evaluated using changes in cell morphology, cell viability, metabolic activity,
and oxidative stress.
o Ag-np reduced A
TP content of the cell caused damage to mitochondria and increased
production of reactive oxygen species (ROS) in a dose-dependent manner.
o DNA damage was also dose-dependent and more
prominent in the cancer cells.
o The transmission electron microscopic (TEM)
analysis indicated the presence of Ag-np inside the
mitochondria and nucleus, implicating their direct
involvement in the mitochondrial toxicity and
DNAdamage.
Optical micrographs of U251 cells without any nanoparticle
treatment (A) and cells treated with Ag-starch (B). Dark orange
patches are visible on the cell surface of the treated cells and
remained even after repeated washings.
TEM images of ultrathin sections of cells. Untreated cells showed no
abnormalities (A), whereas cells treated with Ag-np showed large
endosomes near the cell membrane with many nanoparticles inside (B).
Electron micrographs showing lysosomes with nanoparticles inside (thick
arrows) and scattered in cytoplasm (open arrow). Diamon arrow shows the
presence of the nanoparticle in nucleus (C). Magnified images of
nanogroups showed that the cluster is composed of individual nanopaticles
rather than clumps (D). Image shows endosomes in cytosol that are lodged
in the nuclear membrane invaginations (E) and the presence of
nanoparticles in mitochondria and on the nuclear membrane(F).
35. Summary
⁕ Nanocatalysis plays a central role in both the academic as well as industrial
research and development.
⁕ Industrial impact of nanocatalysis is clearly reflected by the increasing
number of nanocatalysis related patents, technologies and products in the
market.
⁕ Size and shape controlled preparation of metal nanoparticles are very
promising for greener heterogeneous catalytic reactions.
⁕ On the basis of better understanding of size and shape effects of the
nanoparticles and their interactions with support materials or stabilizing
agent, today it is very promising that scientists are able to solve current
environmental, social and industrial problems.