Study On The Effects Of Crystal Orientation And Acid Treatment On The Electrocatalytic Performance Of Pt-based Catalysts

Non-renewable resources such as coal,oil,and natural gas are the main energy sources for human survival.However,due to its limited reserves and environmental pollution,the society is facing severe challenges.Mankind has to study clean and sustainable energy to protect social and economic development.The direct ethanol fuel cell（DEFC）uses ethanol as a fuel,has a high theoretical energy density,and can directly convert chemical energy into electrical energy,which has attracted widespread attention in the society.The core of DEFC is the anode catalyst.The most widely used catalyst is metal Pt,but there are some problems as a catalyst.On the other hand,the process of metal Pt catalyzing the oxidation of ethanol is relatively complex,and its reaction kinetics are relatively slow,resulting in low catalytic efficiency of the catalyst,which hinders the commercialization of metal Pt catalysts.Therefore,the preparation of high-activity,low-cost catalysts is the main direction of research today.This paper proposes a series of solutions to the problems of low utilization of DEFC anode catalyst active materials and low catalytic efficiency.The microstructure of the nano-catalyst was characterized by transmission electron microscopy（TEM）,X-ray diffraction（XRD）,scanning electron microscopy and energy spectroscopy（SEM+EDS）and X-ray photoelectron spectroscopy（XPS）.The electrocatalytic performance of the catalyst was tested by an electrochemical workstation.The effects of crystal plane orientation and acid treatment on the microstructure and catalytic performance of Pt-based catalysts were studied.The results are as follows:Using ethylene glycol to reduce chloroplatinic acid,and by changing the concentration of potassium bromide,a Pt/G catalyst with preferential（100）crystal plane orientation was prepared.Explore the mechanism of exposure（100）crystals to the catalyst performance.The results show that when the Br:Pt molar ratio is 15:1,the（100）crystal plane oriented cubic Pt nanoparticles prepared have a more regular shape and the highest catalytic activity.The electrochemical active surface area is 42.43 m²/g,the peak current density value is 417.67 A/g,and the steady-state current density value is 153.33A/g.It shows that the growth of cubic Pt nanopartic les with（100）crystal plane as the main surface can promote the catalytic oxidation of ethanol and improve the catalytic efficiency of the catalyst.Microwave-assisted reduction of chloroplatinic acid with ethylene glycol,after acid treatment,the AC-PtNi/G catalyst was prepared.Study the effect mechanism of different acid treatment time on the microstructure and catalytic performance of the catalyst.Electrochemical test results show that the AC-PtNi/C-48h catalyst treated with sulfuric acid for 48 h has the highest catalytic activity.Its electrochemical active surface area is76.63 m²/g,the peak current density value is 1218.83 A/g,and the steady-state current density value is 358.77 A/g.In-situ infrared spectroscopy（FTIR）shows that the intensity ratio of CO₂ and CH₃COOH peaks of AC-PtNi/G-48h catalyst is 2.73 times that of Pt/G catalyst.It shows that the AC-PtNi/G-48h catalyst treated with sulfuric acid for 48 h can promote the further progress of ethanol catalytic oxidation reaction,and its catalytic efficiency for ethanol has also been significantly improved.