High Dispersion Construction Of Transition Metal Based Catalytic Active Sites And Their Performance Of Water Electrolysis

Hydrogen energy has become one of the most ideal carriers of renewable energy because of its clean,efficient,pollution-free,renewable and other advantages,which can not only realize decarbonization by consuming power completely,but also improve the efficiency of power grid.Moreover,it can be used in infrastructure industries,such as transportation system,green chemical industry,metal smelting,urban heating and others.Therefore,the development and utilization of green hydrogen energy is of significance to meet the goal of"carbon neutralization"in our country.At present,hydrogen production technology by electrolyzing water is deem as an ideal choice with the advantages of cleaning and non-pollution.But the high overpotential of cathode and anode limits the reduction of the cost of hydrogen.Herein,in order to solve the problems of active site dispersion and efficient utilization of transition metal-based catalysts,the strategies,such as designing unique nanostructures,adding conductive substrates,small molecule coordination and heteroatom doping are adopted to improve the catalytic performance as a whole.At the same time,the methods of ion impregnation,hydrothermal reaction,high temperature gas phase phosphorisation,template etching and so on to optimize the preparation and structure control of the catalyst were systematically studied,and the relationship between formation mechanism and structure-activity was further explored.The related research is not only beneficial to promote the development of water electrolysis industry,but also provides an important reference for the preparation of catalysts with high dispersion active sites.The detailed research contents are as follows:（1）The main results are as follows:using the cobalt cyanide cube as the precursor,the ruthenium ion was loaded on the surface of the nano-cube by ion impregnation,and then the ruthenium ion reacted with oxygen into ruthenium dioxide and highly dispersed on the surface of the cobalt oxide cube by means of high temperature calcination,thus the RuO₂/Co₃O₄ catalyst with high alkaline oxygen evolution performance was prepared.The special nanostructure of the precursor provides a large specific surface area for the loading of the main catalyst.While exposing more active sites,the active sites are also in full contact with the electrolyte solution,thus showing excellent catalytic performance;（2）Using disodium ethylenediamine tetraacetate as ligand,through its chelation with ruthenium ion of precious metal,while adding conductive substrate for the catalyst,the dispersibility of precious metal was improved and the usage of precious metal was reduced.Then ruthenium phosphide nanoparticles with ultra-fine diameter were synthesized by one-step high temperature gas phase phosphating.This experiment provides a reference for the design and preparation of precious metal ruthenium catalysts with high activity and high dispersion from the point of view of small molecules;（3）Nickel-cobalt oxide with nano-sheet structure was synthesized on the surface of silver tungstate cuboid by hydrothermal method,and the silver tungstate carrier was accurately and effectively removed by means of template etching.The characterization of the morphology after gas phase phosphating shows that the prepared nickel-cobalt phosphide catalyst has a hollow structure which is conducive to full contact with the electrolyte.When the designed nickel-cobalt phosphide with unique nanoplate structure is used as the catalyst for water electrolysis,it has the high efficiency of platinum-like hydrogen evolution.