Research On Morphology And Interface Regulation For The Construction Of High-performance Catalysts For Alkaline Water Electrolysi

In order to solve the problem of energy shortage and meet the needs of economic development,it is urgent to develop a novel,clean,efficient and recyclable energy.As a carbon-free,high-energy-density,and easy-to-store secondary green energy,hydrogen is the most ideal and potential energy source for future economic and social development.The water electrolysis reaction is a simple and efficient way to produce hydrogen,which consists of two half-reactions,the hydrogen evolution reaction（HER）and the oxygen evolution reaction（OER）.Although Pt-based catalyst and Ru O₂ are the current state-of-the-art HER/OER catalyst,their high prices and low reserves hinder their large-scale industrial applications.Therefore,it is important to develop a novel,efficient and inexpensive catalyst.Most advanced methods to improve catalyst activity mainly include adjusting elemental composition,such as preparing alloy catalysts,doping of heteroatoms and modulation of morphology and interface engineering,such as nanosheets,nanowires,layered structures,heterostructures,etc.Based on these ideas,this article aims to improve the intrinsic activity of catalysts through morphology control and heterostructure construct.Transition metal phosphides have become a promising new type of water electrolysis catalyst due to their structure and special physicochemical properties.In this paper,a Co Ni P catalyst supported on nickel foam was prepared by a simple pulse electrodeposition method.By adjusting the ratio of metal salts in the plating solution,the nanomorphology of the samples can be controlled.The research shows Ni P/NF have three-dimensional spherical morphology but it shows lower electrocatalysis activity due to the small specific surface area.In contrast,Co P/NF possess large scale two-dimensional nanosheet structure with agglomeration,so the edge active sites are not easy to contact electrolytes,which increases the mass transfer resistance.Surprisingly,Co₆Ni₄P/NF express three-dimensional flower ball nanoclusters,this morphology retain the three-dimensional structure,increase the exposure of edge active sites.Its porous structure also facilitates mass transfer and exhibits the best OER catalytic performance.The overpotential at industrial high current(1000 m A cm^-2)is only 373m V,the Tafel slope is 63 m V dec^-1.Meanwhile,it can work stably over 60 hours at the different current density.Ru is the most promising HER catalyst to replace Pt because of its unique physicochemical properties and low price（about one sixth of Pt）.In this paper,Ru/RuO₂ was successfully synthesized by a simple hydrothermal method combined with high temperature pyrolysis.The heterostructures are supported on modified multi-walled carbon nanotubes,and the results show that the pyrolysis temperature plays a crucial role in the crystal formation of Ru/RuO₂,in which the Ar-500 sample exhibits comparable performance as the Pt/C catalyst under alkaline conditions.Electrochemical tests show the Ar-500 has great HER performance,its overpotential only 57 m V at a current density of 10 m A cm^-2 and Tafel slope is 49.8 m V dec^-1.According CP test,Ar-500 retains 90.21%catalytic performance after 50,000 s stability test.