September 25, 2020

China University of Science and Technology Progress in Electrocatalytic Hydrogen Evolution of Carbon-Based Catalysts

[ Instrument Network Instrument Development ] In recent years, electrolyzed water hydrogen production has received extensive attention, and finding cheap and efficient electrocatalysts that can replace precious metals has become a hot research topic. Graphene has attracted a lot of attention from researchers because of its good electrical conductivity, excellent chemical stability and easy chemical modification. It is committed to developing it into a highly active electrolyzed water hydrogen catalyst. It has been shown that the doping of heteroatoms such as nitrogen can regulate the electronic structure of the carbon atoms of the adjacent atoms, enhance the adsorption of the active sites of the carbon atoms and the reaction intermediates, and improve the electrocatalytic hydrogen evolution of carbon-based materials such as graphene. Performance, however, the traditional pyridine, pyrrole and graphite nitrogen doping modes have poor performance for the performance control of carbon-based catalysts such as graphene, and there is still a large gap compared with the reported high activity metal-based catalysts.
Researchers at the University of Science and Technology of China have discovered by density functional theory calculation (DFT) that double graphite nitrogen doping in a six-membered graphene lattice can significantly change the carbon atoms in a material (carbon atoms bonded to two nitrogen atoms). The electronic structure reduces the ΔGH* value of the carbon active site to very close to 0 eV, which is expected to further increase the hydrogen evolution catalytic activity of the carbon-based material. In this study, Cu-BTC, a metal organic framework compound, was used as a precursor. The graphene-like particle aggregates were obtained by calcination and solvent heat treatment. After CV circulation, the acid electrocatalytic hydrogen evolution performance was gradually improved. When the optimum value was reached, at 10 mA. The overpotential at /cm2 current density is only 57mV, and the Tafel slope is 44.6 mV/dec, showing electrocatalytic hydrogen evolution performance comparable to the reported high activity metal based catalysts and Pt/C catalysts. The characterization of infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray near-edge absorption fine structure and solid-state NMR showed that the carbon-based material formed a new structure of double graphite nitrogen doped in a graphene lattice six-membered ring. Two adjacent graphite-type nitrogen-bonded carbon atoms are catalytically active sites, and the bonding mode is advantageous for enhancing the adsorption of H on the C active site, thereby improving catalytic activity.
The research results are published online in the international journal "German Applied Chemistry" (Dang Graphitic-N Doping in a Six-Membered C-Ring of Graphene-Analogous Particles Enables an Efficient Electrocatalyst for the Hydrogen Evolution Reaction) (Angew. Chem. Int. Ed DOI: 10.1002/anie.201908210).
Chen Ganwang, professor of materials at the Hefei Microscale Physical Science Research Center and the School of Chemistry and Materials Science of China University of Science and Technology, is the author of the paper. Lin Zhiyu, a Ph.D. student at China University of Science and Technology, and Yang Yang, a postdoctoral fellow, are the co-first authors of the paper. Hefei Synchrotron Radiation National Laboratory, Shanghai Synchrotron Radiation Source and Hefei Steady Strong Magnetic Field Center provided important help for the analysis of experimental results. The research was funded by the National Natural Science Foundation of China.

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