High-Density Cobalt Single-Atom Catalysts for Enhanced Oxygen Evolution React...Pawan Kumar
ย
Single atom catalysts (SACs) possess unique catalytic properties due to low-coordination and unsaturated active sites. However, the demonstrated performance of SACs is limited by low SAC loading, poor metalโsupport interactions, and nonstable performance. Herein, we report a macromolecule-assisted SAC synthesis approach that enabled us to demonstrate high-density Co single atoms (10.6 wt % Co SAC) in a pyridinic N-rich graphenic network. The highly porous carbon network (surface area of โผ186 m2 gโ1) with increased conjugation and vicinal Co site decoration in Co SACs significantly enhanced the electrocatalytic oxygen evolution reaction (OER) in 1 M KOH (ฮท10 at 351 mV; mass activity of 2209 mA mgCoโ1 at 1.65 V) with more than 300 h stability. Operando X-ray absorption near-edge structure demonstrates the formation of electron-deficient Co-O coordination intermediates, accelerating OER kinetics. Density functional theory (DFT) calculations reveal the facile electron transfer from cobalt to oxygen species-accelerated OER.
Neutron diffraction is the application of neutron scattering to the determination of atomic/ magnetic structure of a material. The technique is similar to XRD but the different type of radiation gives complementary radiation. It is of different types and overcomes the demerit of XRD. It has a lot of applications such as structure determination, locating light atoms, magnetic properties study, study of atomic vibration and other excitations.
in this lesson, I mention bond characteristics.in bond characteristics we divide it into three parts the first one is the bond length, then bond energy and the third one is about the bond angle, how and why they are formed this important and basic topic.
High-Density Cobalt Single-Atom Catalysts for Enhanced Oxygen Evolution React...Pawan Kumar
ย
Single atom catalysts (SACs) possess unique catalytic properties due to low-coordination and unsaturated active sites. However, the demonstrated performance of SACs is limited by low SAC loading, poor metalโsupport interactions, and nonstable performance. Herein, we report a macromolecule-assisted SAC synthesis approach that enabled us to demonstrate high-density Co single atoms (10.6 wt % Co SAC) in a pyridinic N-rich graphenic network. The highly porous carbon network (surface area of โผ186 m2 gโ1) with increased conjugation and vicinal Co site decoration in Co SACs significantly enhanced the electrocatalytic oxygen evolution reaction (OER) in 1 M KOH (ฮท10 at 351 mV; mass activity of 2209 mA mgCoโ1 at 1.65 V) with more than 300 h stability. Operando X-ray absorption near-edge structure demonstrates the formation of electron-deficient Co-O coordination intermediates, accelerating OER kinetics. Density functional theory (DFT) calculations reveal the facile electron transfer from cobalt to oxygen species-accelerated OER.
Neutron diffraction is the application of neutron scattering to the determination of atomic/ magnetic structure of a material. The technique is similar to XRD but the different type of radiation gives complementary radiation. It is of different types and overcomes the demerit of XRD. It has a lot of applications such as structure determination, locating light atoms, magnetic properties study, study of atomic vibration and other excitations.
in this lesson, I mention bond characteristics.in bond characteristics we divide it into three parts the first one is the bond length, then bond energy and the third one is about the bond angle, how and why they are formed this important and basic topic.
Pyrolysis is a thermochemical treatment, which can be applied to any organic (carbon-based) product. It can be done on pure products as well as mixtures. In this treatment, material is exposed to high temperature, and in the absence of oxygen goes through chemical and physical separation into different molecules.
The all the content in this profile is completed by the teachers, students as well as other health care peoples.
thank you, all the respected peoples, for giving the information to complete this presentation.
this information is free to use by anyone.
Synthesis and Characterization of MOF based Composites for Energy storage app...Danyal Hakeem Jokhio
ย
Despite extensive efforts and research put in the field, conventional energy storage devices (ESDs) such as various supercapacitors and batteries are near their performance limit in terms of power densities, energy densities, capacitance, charge retention, and cyclic stability. This is primarily due to limiting intrinsic properties of the electrode materials such as average surface area and poor porosity, combined with sluggish redox kinetics due to lack of electrode functionality. So, the need of the hour is to explore new materials for efficient storage of the energy. Among these new materials, metal-organic frameworks (MOFs) can serve as potential candidates because they have high specific surface area, high porosity with tuneable morphology and hence tuneable pore size, functionality linking to active metal sites and ligands. However, there remains a gap in fully utilising MOFs in energy storage applications commercially. Due to the highly porous nature of MOFs, their structural stability is compromised especially in aqueous electrolytes. To utilize the maximum potential of MOFs as electrode materials, it is of utmost importance to address poor structural integrity and low intrinsic conductivity of MOFs.
In this work, it has been tried to overcome the above-mentioned drawbacks of MOFs by using additives of conductive nature such as graphene nanoplatelets (GNP). Hydrothermal approach was used to synthesize hybrid MOF by controlling molar ratio of Nickel and Cobalt in combination with different organic ligands. As a battery-type supercapacitor electrode material, the 2:1 Ni/Co hybrid MOF with 40mg GNP, using terephthalic acid as ligand, delivered a high specific capacity of 658.8 Cยทgโ1 at the current density of 1 Aยทgโ1. Similarly, the 1:2 Ni/Co hybrid MOF, using 2-MethylImidazole as ligand, delivered a high specific capacity of 642.4 Cยทgโ1 at the current density of 1 Aยทgโ1. Moreover, breakthrough results were obtained by optimizing synthesis with in-situ deposition on nickel foam of 2:1 Ni/Co (with 40mg GNP) hybrid MOF, which produced an impressive specific capacity of 1264 Cยทgโ1 at 1 A/g, surpassing, to the best of our knowledge, most of the previously reported MOF based electrode materials.
This work not only develops a high-performance electrode material of supercapacitor, but being the first of its kind in Pakistan, also provides the foundation of systematic research for the electrochemical properties of multi-metal MOFs.
introduction to DSSC, Principle and working of DSSC,Component involved in DSSC, how does DSSC work?,Advantage and disadvantage of DSSC, application of DSSC.
Pyrolysis is a thermochemical treatment, which can be applied to any organic (carbon-based) product. It can be done on pure products as well as mixtures. In this treatment, material is exposed to high temperature, and in the absence of oxygen goes through chemical and physical separation into different molecules.
The all the content in this profile is completed by the teachers, students as well as other health care peoples.
thank you, all the respected peoples, for giving the information to complete this presentation.
this information is free to use by anyone.
Synthesis and Characterization of MOF based Composites for Energy storage app...Danyal Hakeem Jokhio
ย
Despite extensive efforts and research put in the field, conventional energy storage devices (ESDs) such as various supercapacitors and batteries are near their performance limit in terms of power densities, energy densities, capacitance, charge retention, and cyclic stability. This is primarily due to limiting intrinsic properties of the electrode materials such as average surface area and poor porosity, combined with sluggish redox kinetics due to lack of electrode functionality. So, the need of the hour is to explore new materials for efficient storage of the energy. Among these new materials, metal-organic frameworks (MOFs) can serve as potential candidates because they have high specific surface area, high porosity with tuneable morphology and hence tuneable pore size, functionality linking to active metal sites and ligands. However, there remains a gap in fully utilising MOFs in energy storage applications commercially. Due to the highly porous nature of MOFs, their structural stability is compromised especially in aqueous electrolytes. To utilize the maximum potential of MOFs as electrode materials, it is of utmost importance to address poor structural integrity and low intrinsic conductivity of MOFs.
In this work, it has been tried to overcome the above-mentioned drawbacks of MOFs by using additives of conductive nature such as graphene nanoplatelets (GNP). Hydrothermal approach was used to synthesize hybrid MOF by controlling molar ratio of Nickel and Cobalt in combination with different organic ligands. As a battery-type supercapacitor electrode material, the 2:1 Ni/Co hybrid MOF with 40mg GNP, using terephthalic acid as ligand, delivered a high specific capacity of 658.8 Cยทgโ1 at the current density of 1 Aยทgโ1. Similarly, the 1:2 Ni/Co hybrid MOF, using 2-MethylImidazole as ligand, delivered a high specific capacity of 642.4 Cยทgโ1 at the current density of 1 Aยทgโ1. Moreover, breakthrough results were obtained by optimizing synthesis with in-situ deposition on nickel foam of 2:1 Ni/Co (with 40mg GNP) hybrid MOF, which produced an impressive specific capacity of 1264 Cยทgโ1 at 1 A/g, surpassing, to the best of our knowledge, most of the previously reported MOF based electrode materials.
This work not only develops a high-performance electrode material of supercapacitor, but being the first of its kind in Pakistan, also provides the foundation of systematic research for the electrochemical properties of multi-metal MOFs.
introduction to DSSC, Principle and working of DSSC,Component involved in DSSC, how does DSSC work?,Advantage and disadvantage of DSSC, application of DSSC.
๊ณ ์๋ฐ์๊ธฐ๋ ๋ค์ํ ์คํ์ ์ํํ๊ธฐ ์ํ ๋ค๋ชฉ์ ์ฉ ๋ฐ์๊ธฐ์ ์คํฉ๋ฐ์๊ธฐ, ์ด๊ณ ์จ/์ด๊ณ ์๋ฐ์๊ธฐ, ๊ทธ๋ฆฌ๊ณ ํน์ํ ์คํ ๋ฐ ์์ฐ์ ์ํํ๊ธฐ ์ํ ์คํ์ ๋ฐ์๊ธฐ๋ก ๋ถ๋ฅํ์ฌ ์ ์ํฉ๋๋ค.
It has diverse applications which are hydrothermal and decomposition, sublimation, extraction in laboratory by high pressure and temperature with various optional device.