Synthesis Of Ag-Cu Nano Alloy And Its Hydrogen Evolution Performance Based On Microfluidic Reactor

With people's increasing attention to environmental and energy issues,traditional fossil fuels have become increasingly difficult to meet people's needs.The electrolysis hydrogen technology,which can convert renewable energy such as solar energy and wind energy into hydrogen energy,has been paid more and more attention by researchers because of its advantages of no pollution,high efficiency and zero emission.In the process of hydrogen production by electrolysis,catalytic materials play an important role.Efficient catalytic materials can directly reduce the over potential of hydrogen evolution and production cost.In this paper,single-phase Ag-Cu alloy nanomaterials were prepared by liquidphase reduction method,and their catalytic activity in electrochemical hydrogen evolution was investigated.By introducing the reaction system into the microfluidic system,the single-phase Ag-Cu alloy nanoparticles and nano silver nanoparticles were prepared.The morphology and structure of single-phase Ag-Cu alloy nanoparticles were characterized by SEM,XRD and UV Vis,and the possible formation mechanism was analyzed.Based on the method of liquid-phase reduction,single-phase Ag-Cu alloy nanoparticles with different composition were prepared by controlling the ratio of silver to copper in the precursor.The effects of different reducing agents and complexing agents on the reduction process were analyzed.The catalytic activity of Ag-Cu alloy nanoparticles for hydrogen evolution was studied.Linear sweep voltammetry and Tafel tests were carried out on the synthesized nano alloy materials.The results show that the hydrogen evolution activity of the singlephase Ag-Cu alloy nanoparticles is higher than that of pure Ag and Cu.Among them,the exchange current density of the alloy nanoparticles with 70 % copper content can reach 5.1 times of that of pure silver,and 4.7 times of that of pure copper.It can be seen that the hydrogen evolution activity of the Cu atoms can be further improved after entering the silver lattice.The results show that the electron orbit of Cu atom shifts and the bond energy of Cu-H bond increases due to the growth of Cu attached to Ag lattice,and the hydrogen evolution activity of Cu increases.In order to further clarify the formation mechanism of single-phase Ag-Cu alloy nanoparticles,the reaction system was introduced into the microfluidic system.By adjusting the reaction temperature and reaction time,the single-phase Ag-Cu alloy nanoparticles and nano silver nanoparticles were prepared.The effects of different process parameters on the morphology and structure of the products were analyzed.It was determined that the single-phase Ag-Cu alloy nanoparticles: complexing agent promoted the reduction of Ag+ and inhibited the reduction of Cu2+,reducing Cu0 was difficult to reach the critical nucleation concentration.Due to the similar lattice structure of silver and copper,the single-phase Ag-Cu alloy nanoparticles are formed by the growth of copper atoms relying on the lattice of Ag.The temperature,pressure and speed of the microfluidic system are simulated by using the finite element analysis software COMSOL Multiphysics.The optimization and improvement measures for the microfluidic system are proposed to improve its production efficiency and heating mode.Based on the coaxial microchannel and Ttype microchannel,the structure of the microfluidic system was optimized to disperse the reaction liquid to realize the function of single drop reaction.