Preparation And Electrocatalytic Properties Of High-performance Noble Metal Catalysts

Due to its merits such as high energy density,only water released when converted,clean and pollution-free,safe and reliable,etc.,hydrogen energy is considered to be the most potential clean energy in the 21st century.At present,hydrogen is mainly produced through the steam reforming method,while it consumes a huge amount of energy and meanwhile produces greenhouse gases such as carbon dioxide.Water splitting has been proved as a clean and sustainable hydrogen production method,but the precious metal platinum catalyst used in this method has drawbacks such as high cost,poor operational stability and poor anti-poisoning.Therefore,it is urgent to develop new low-cost electrocatalysts with high activity and high stability.In order to improve the utilization of platinum atoms,regulating the composition and structure of catalysts on the nanoscale,introducing non-noble metals into the bulky construct of the noble metals,utilizing the synergy between metals,enhance electron transfer,shorten diffusion distance,and developing high catalytic activity and stable low-platinum catalyst are the current research hotspots.This thesis aims to design and prepare low-Pt electrocatalysts with excellent catalytic activity and stable performance,which can be used in the fields of hydrogen production by electrolysis of water and hydrogen fuel cells electrocatalysis.In order to improve the utilization of precious metal platinum in nano-metal catalysts,a series of nano-alloy catalysts were prepared by solvothermal co-reduction and transition metal template method.The micro-structure,morphology and electrochemical performance test of the catalysts were carried out.The main research contents and results are as follows:Taking platinum nickel nanoparticles as the research object,the effects of different metal precursor ratios and different surfactant usage amounts on catalytic activity were examined.（1）Preparation of platinum nickel nano-alloy catalyst by solvent co-reduction method.The controlled variable method was used to explore the effects of metal ratio,reducing agent addition,and acid treatment on the surface morphology and electrocatalytic performance of nanoparticles.The different characterization and performance tests showed that the optimized conditions include the atom ration of Pt/Ni is 1:4,the SDS surfactant content is 9 m M,which yielded the Pt Ni nanoparticles with an average particle size of 3.1 nm.ICP-MS test and electrocatalytic hydrogen evolution test results show that when the composition of the nanoparticle catalyst is Pt₃₈Ni₆₂/C exhibits the best electrocatalytic hydrogen evolution（HER）performance.（2）The platinum nickel alloy catalyst was prepared by the transition metal template method.First,nano-nickel particles are synthesized as a template.Chloroplatinic acid solution was added to the reaction system,and the precious metal platinum was reduced by the nano-nickel particles to form a nano-alloy catalyst.Different molar amounts of Ni were selected to prepare the alloy catalysts.Electrochemical test results showed that under the same metal loading conditions,Pt Ni/C exhibited the best HOR catalytic activity among a series of platinum-nickel alloy catalysts.