Preparation Of Mo,Co,Ni-based Composites And Study On Hydrogen Production By Electrolytic Water

With a continuously increasing concern on energy and environmental issues in the world at present,the development of new energy based on low-carbon and renewable resources is particularly important for social sustainable development.Hydrogen?H₂?as a green energy source is expected to solve the above problems and open up new paths for the future carbon-free energy economy.Electrolyzed water is a green and efficient hydrogen production method that can meet the growing demand for renewable energy and clean energy.As one of the important components of electrocatalytic water splitting,the catalysts determine the energy transfer efficiency of the hydrogen evolution reaction?HER?.It is generally known that platinum-based electrocatalysts are the most active electrolysis water hydrogen evolution catalysts because of their high activity and low Tafel slope.However,suffering from the scarcity and high cost,the practical application of Pt based catalysts is seriously limited.Therefore,the development of cost-effective,effective and non-precious metals electrotrocatalysts is an urgently requirement for practical application.During the last decade,transition metal compounds,like Mo-,Co-,Ni-based and their compounds,have been extensively studied because of their low price.Nonetheless,their performance is still far from that of Pt-based catalysts.Herein,this paper mainly studies the preparation of Mo-,Co-,Ni-based and their composites and the hydrogen production performance of electrolytic water.The main research contents are as follows:?1?MoP/N,P-C nanosheet composites were successfully prepared by using a simple one-step calcination strategy using molybdenum chloride,melamine and phytic acid as raw materials.MoP/N,P-C-900 is an N,P-C nanosheet uniformly loaded with MoP particles of about 100 nm.This structure shows a rich mesoporous structure and increases the exposure of active sites.It only takes 129mV to reach 10mA cm^-2,and the Tafel slope is 57.37 mV dec^-1in acid solution.It also shows excellent hydrogen evolution performance compared with the Pt/C electrode tested together.?2?Carbon cloth was used to the conductive substrate,ZnCo-MOF on a carbon cloth was synthesized through a hydrothermal reaction,and then subjected to carbonization and sulfurization in a nitrogen atmosphere to prepare a CoS₂/N-C nanosheet on conductive substrate.Interaction between CoS₂ and nitrogen doped carbon nanosheet accelerate the conduction between electrons.In particular,CoS₂/N-C-0.1 has a rich mesoporous structure with a specific surface area of 6.204 m2g^-1.It takes only 119 mV to reach 10 mA cm^-2,and the Tafel slope is 73.55 mV dec^-11 in 0.5M H₂SO₄ electrolyte.?3?The nanoneedle-shaped NiCo₂S₄ was synthesized on carbon cloth by hydrothermal method,and then the NiCo₂S₄@NiCo-LDHs nanoflower on carbon cloth was prepared by further hydrothermal method.NiCo₂S₄,NiCo-LDHs,and NiCo₂S₄@NiCo-LDHs require overpotentials of 237 mV,576 mV,and 183 mV,respectively,to achieve a current density of10 mA cm^-22 in 0.5M H₂SO₄.Compared with NiCo₂S₄ and NiCo-LDHs,the hydrogen evolution performance has been greatly improved.