Controllable Synthesis And Electrocatalytic Performance Of Copper-based Nanomaterials

Electrochemical technology is a powerful tool for reducing the misuse of natural resources.Over the past many years,people have devoted themselves to the development of new energy and the synthesis technology of high value-added products based on electrochemistry.It has been found that the production of high-purity green hydrogen by electrochemical water splitting driven by renewable electricity is a promising technology.Typically,electrochemical water splitting systems involve the hydrogen evolution reaction（HER）and oxygen evolution reaction（OER）on the cathode and anode,respectively.Finding low-cost electrocatalysts with high and stable activity for both HER and OER is the key to reducing the reaction overpotential.Although people always research and develop various electrocatalysts,so far,catalysts for HER and OER are mainly concentrated in noble metal systems,such as platinum（Pt）,iridium（Ir）,and ruthenium（Ru）-based electrocatalysts.However,the scarcity of precious metal catalysts hinders the practical application of industrialization.Therefore,low-cost electrocatalysts with excellent or comparable catalytic activities are highly desired,and the most important part to improve the performance of these electrochemical reactions is the rational design and development of electrocatalysts.In the present paper,we developed a copper-based,one-pot self-template strategy to fabricate a series of copper-based alloy nanotubes by wet chemical etching.Including CuNi nanotubes,CuNiCo nanotubes,CuNiCo Fe Ru nanotubes,CuNiCo Fe Ru Ga nanotubes,CuNiCo Fe Ru Ga Rh nanotubes.In addition,during the synthesis experiments,the Kirkendall effect and displacement reaction played a large role in the formation of the hollow structure.Five kinds of alloy nanotubes were then used as catalysts for electrochemical HER and OER.In alkaline solution,CuNiCo Fe Ru alloy nanotubes with low noble metal Ru content were found to exhibit excellent hydrogen evolution and oxygen evolution performance.Compared with the other four catalysts,CuNiCo Fe Ru alloy nanotubes achieved the lowest overpotential（48 m V）and the smallest Tafel slope(161 m V·dec^-1)in the HER reaction.In the OER reaction,CuNiCo Fe Ru alloy nanotubes also showed the lowest overpotential（232 m V）and the smallest Tafel slope(151m V·dec^-1)（much better than commercial Ru O₂）.Besides,CuNiCo Fe Ru nanotubes also exhibit relatively large electrochemically active area and good reaction kinetics,as well as excellent stability.