Preparation Of Cobalt-based Electrocatalyst By Electroless Plating And Electrocatalytic Performance

Hydrogen production from renewable energy can realize the lowest carbon emission in the industrial chain,which is of great significance for promoting our country to realize double carbon goal,and establishing green and low carbon circular development economy.Among the various hydrogen production technologies,electrochemical decomposition of water is considered to be the most economical and simplest strategy.Platinum,iridium and other precious metal-based catalysts are internationally recognized as the most efficient electrolytic and hydroelectric catalysts.However,due to high production cost and scarce reserves on earth,large-scale industrial applications are hindered.Therefore,the development of stable and effective transition metal electrocatalysts is very important for the hydrogen industry.Transition metal cobalt has attracted much attention because of its abundant crustal content and unique electronic structure.Based on this,three different cobalt-based catalysts were prepared by electroless plating with three different materials as precursors,and their structure,characterization and catalytic activity were studied.The main content of the paper is as follows:1)Using dopamine hydrochloride as carbon and nitrogen sources,Pluronic F127 as soft template and 1,3,5-tritylene as mediator,the nitrogenous mesoporous carbon nanospheres MCSs were synthesized.Then,cobalt-based oxygen evolution catalyst Co B/MCSs was constructed by powder electroless plating of cobalt boron.By changing the reaction time and temperature of electroless plating,the electrode material with the best electrocatalytic performance was investigated.In alkaline electrolyte,the oxygen evolution performance is the best when the bath temperature is 30℃and the reaction time is 2 h.The three-dimensional structure of MCSs as a carrier reduces the transport resistance of electrons in the electrolyte and exposes more active sites,thus enhancing the electrochemical activity of the catalyst.2)As the powder catalyst is easy to fall off,the 3D structure nickel foam（NF）was used as the base,and the regular dodecahedron ZIF-67 was synthesized by solvent method at room temperature as the precursor.The heterogeneous structure catalyst Co PB@ZIF-67/NF was prepared by electroless plating deposition of cobalt,phosphorus and boron（Co PB）as the self-supporting electrode for high efficiency hydrogen evolution.The in-situ growth of ZIF-67 and Co PB nanosheets on NF can ensure the seamless interface contact between the components and the substrate,enhance the overall conductivity of the catalyst and prevent the aggregation of the components.The synthesized ZIF-67 precursor has a large specific surface area of 1706.404 m²·g^-1.The effect of electroless plating time on catalyst morphology and hydrogen evolution performance was also studied.It was found that the morphology of nano-sheet was the best when the reaction time was 2 h,and the hydrogen evolution effect was also the best.3)Graphitized carbon nitride（g-C₃N₄）was obtained by carbonization of urea as nitrogen source and carbon source,and Co PB was deposited by electroless plating.Co PB/g-C₃N₄/NF was a bifunctional catalyst.g-C₃N₄ has a special electron band structure and good physical and chemical stability,and the chemically coupled boundary with Co PB induces electron transfer,which is conducive to electrolyte penetration,increase the active site,and improve the catalytic activity.Co PB/g-C₃N₄/NF is used for integral water cracking up to 10 m A cm^-2 at a voltage of 1.5 V.