Preparation Of Ru(Os)-Modified Cobalt-Based Catalysts And Their Performance For Water Electrolysis

The goal of"carbon neutrality and carbon peaking"has strongly promoted the research and development of clean energy and related materials in our country.Among many clean energy sources,hydrogen has high expectations due to its non-polluting and high energy density.Hydrogen production by electrolysis of water is environmentally friendly and only consumes common water resources,and this method of hydrogen production can be combined with our country’s advantages in using photovoltaics and wind power to generate electricity,so it has a very broad application prospect.However,the hydrogen evolution reaction（HER）of water electrolysis is too dependent on the precious Pt,while the oxygen evolution reaction（OER）is too dependent on the precious metal-based Ru O₂ and Ir O₂,and its high price and scarcity greatly hinder the development of this hydrogen production technology.Although the research of non-precious metal catalysts has made great progress in the past period,the performance is still not comparable to that of noble metal catalysts.Therefore,the development of non-noble metal catalysts with high performance and low cost is crucial for realizing large-scale water electrolysis for hydrogen production.In this regard,this paper mainly focus on the following aspects:1.A V-doped Ni₂P/Co P heterostructure material modified by Ru nanoparticles（Ru V-Co Ni P/NF）was prepared.The preparation process includes three steps.First of all,a vanadium doped Co-based layered double hydroxide based on foamed nickel（V-Co-LDH/NF）is synthesized by hydrothermal method.After immersion in the Ru Cl₃solution,the sample was dried thoroughly.Finally,the V-doped Ni₂P/Co P heterostructure catalyst assisted with Ru nanoparticles can be prepared by high temperature gas phase phosphating.The catalyst can effectively drive the hydrogen evolution reaction(28 m V@10 m A cm^-2)and oxygen evolution reaction(214 m V@20m A cm^-2).When it applied to the overall water splitting devices,the current density of10 m A cm^-2 can be achieved with a voltage of only 1.469 V.It is worth noting that Ru V-Co Ni P/NF//Ru V-Co Ni P/NF can still efficiently catalyze the decomposition of water in the harsh environment of alkaline seawater.At the current density of 20 m A cm^-2,their corresponding overpotential is 1.538 V,which is better than the commercial Ru O₂/NF//Pt/C/NF catalyst pair（1.678 V）.2.Metal organic framework（MOFs）are considered as good catalyst precursors because of their broad specific surface area,variable and adjustable structure and diverse porosity.A cobalt atomic catalyst was synthesized by pyrolysing cobalt based zeolitic imidazole framework（ZIF-67）as precursor.A nitrogen doped carbon material anchored with Os particles and Co atoms(Os-Co _SANC)was prepared by using the carbon material with cobalt single atom as the substrate to load osmium particles.The catalyst showed excellent acidic and alkaline HER activity.In 0.5 M H₂SO₄,the overpotential of the catalyst at 10 m A cm^-2 is 28 m V.In 1 M KOH,the over potential of the catalyst driving 10 m A cm^-2 is 19 m V.Importantly,the performance of the catalyst is better than that of commercial Pt/C in both acidic and alkaline electrolytes.