Study On The Electrocatalytic Performance Of Carbon Supported PtZn Intermetallic Compounds And Fe-Co Double Atoms Catalysts For Oxygen Reduction

Fuel cells and metal-air batteries have broad application prospects as green and clean energy sources,providing solutions to the shortage of non-renewable resources.Oxygen reduction reaction（ORR）is an important reaction of fuel cell and metal-air battery cathode,and its slow kinetics restricts the performance of the battery.Therefore,it is necessary to develop new high-performance ORR catalyst materials.In long-term research,researchers have improved Pt particles with excellent performance to form platinum-based alloys,thereby overcoming the shortcomings of Pt catalysts such as expensive,easy to inactivate and poor stability.At the same time,transition metal single-atom catalysts have also been widely studied as ORR catalysts to completely replace noble metal Pt due to their advantages of high atomic utilization,high catalytic activity and low cost.Firstly,the PtZn ordered intermetallic compound（PtZn N/NC）with compressive strain was successfully synthesized in this paper,and the high-efficiency ORR catalytic performance in different p H solutions was realized.The structure-activity relationship of PtZn N/NC catalyst was studied by X-ray diffraction,X-Ray Photoelectron Spectroscopy,Extend X-ray Absorption Fine Structure The catalyst exhibits better ORR catalytic performance than commercial Pt/C,with half-wave potentials of 0.892 V and0.864 V vs.RHE in acidic and basic solutions,respectively,and excellent long-term stability.A maximum power density of 119 m W cm^-2 is also exhibited when assembled into zinc-air batteries.Theoretical calculations show that the good performance of the catalyst is attributed to N doping,resulting in a decrease in the ORR reaction energy barrier.Secondly,in order to realize the complete substitution of precious metal Pt and obtain the same excellent ORR catalytic performance,Fe-Co atoms were loaded on N-doped porous carbon materials by dissolution carbonization method.The structure study shows that Fe and Co elements exist in the form of single atoms,and the active sites are uniform and dispersed,which makes the catalyst have excellent catalytic activity and stability.At the same time,the ORR half-wave potential of up to 0.892 V vs.RHE in alkaline solution was obtained by the synergistic effect between Fe-Co atoms,and shows better battery performance than commercial Pt/C in the test of zinc-air battery.