Preparation And Electrocatalytic Properties Of Au-Pd Bimetallic Nanocomposites Based On Carbon Quantum Dots

With the rapid development of modern social economy,the contradiction between traditional fossil fuels and environmental protection is becoming increasingly acute.The potential crisis of energy shortage makes research for development of clean and efficient new energy resources extremely urgent.Fuel cell and hydrogen are clean energy sources that have attracted wide attention in recent years.Among them,the direct methanol fuel cell(DMFC)has the advantages of high energy density,simple operation,low operating temperature and easy portability.It has become a promising candidate for future energy storage and conversion equipment.Meanwhile,among various technologies for hydrogen production,the advantages of electrolyzed water such as simple operation and mature technology,which have gained extensive attention from researchers.The design of efficient catalysts is a key in DMFC and electrolyzed water hydrogen production technology.A large number of research results show that the precious metal platinum and platinum-based catalysts are currently the most effective catalysts.However,the high cost,low reserves and low durability of platinum have largely impeded their large-scale commercial applications.In view of the above background,three works were carried out in this paper as follows:(1)Based on nitrogen-doped carbon quantum dots(N-CQDs),three layers core-shell metal composite nanomaterial(Au@N-CQDs@Pd)with Au nanoparticle as core,N-CQDs as intermediate layer and Pd nanoparticle as shell was synthesized by two-step reduction method.The results showed that N-CQDs had good dispersion properties for Pd nanoparticles and played an important role in the stability of the core-shell structure.Simultaneously,owing to this method did not need to use any surfactants and organic reagents in the synthesis process,it was a green synthesis method.(2)The electrocatalytic performance of Au@N-CQDs@Pd synthesized at different temperature conditions for methanol was studied by electrochemical techniques in alkaline media.Compared with Au-Pd,it was found that the addition of N-CQDs greatly improved the catalytic activity for methanol.Au@N-CQDs@Pd synthesized at 20°C exhibited the best catalytic activity and resistance to CO poisoning due to more active sites were exposed.(3)The electrochemical hydrogen evolution performance of Au@N-CQDs@Pd synthesized at different temperature was studied.The results showed that the Au@N-CQDs@Pd synthesized at 20°C had lower overpotential,smaller Tafel slope and more excellent electrochemical durability.