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Controllable Construction Of Bimetallic Electrocatalysts And Their Applications In Small Molecule Catalysi

Posted on:2024-08-06Degree:MasterType:Thesis
Country:ChinaCandidate:Z B ZhaoFull Text:PDF
GTID:2531307094992619Subject:Physical chemistry
Abstract/Summary:PDF Full Text Request
Electrocatalytic carbon dioxide reduction(CO2RR)is the most potential method to solve the negative impact of high CO2content on global climate change.However,there are still some challenges,such as poor selectivity,low current density and high energy consumption,and most of the catalysts that can exert excellent performance are precious metal catalysts.At the same time,electrocatalytic oxygen evolution reaction(OER),as the core reaction of converting renewable electric energy into storable fuel,plays an indispensable role in CO2RR.However,it is challenging in dynamics because of its complex multi-electron transfer process.In this paper,based on the design and synthesis of cheap and stable electrocatalysts,a highly efficient electrocatalyst with bimetallic active sites was successfully constructed through the strategy of carbon coating,which manifests excellent catalytic performance in CO2RR and OER.The main research contents are as follows:(1)A highly efficient electrocatalyst(Ni AD/Ag NPs@CN)loaded with atom dispersed Ni3and Ag nanoparticles(Ag NPs)active sites on the surface of N-doped carbon(CN)substrate was prepared by carbon coating strategy and applied to CO2RR.The electrochemical test results show that the synthesized catalyst Ni AD/Ag NPs@CN shows excellent performance in CO2RR.The Faraday efficiency(FECO)of carbon monoxide is close to 100%(up to 99.97%)at-0.88 V(vs.RHE)overpotential,and the FECOis more than 90%in the range of-0.68 V~-1.08 V(vs.RHE)potential.Density functional theory(DFT)calculation results reveal that the atomic dispersed nickel active sites can effectively improve the adsorption of CO2on silver nanoparticles,thus obviously reducing the energy barrier of the generated of*COOH intermediates and the desorption of*CO,and significantly improving the catalytic activity.(2)Non-noble bimetallic oxide(Fe3O4and Ni O)catalysts with uniform distribution on the surface of CN substrate were prepared by hydrothermal and high temperature calcination methods and used in OER.The electrochemical performance test results illuminate that the prepared catalyst Fe3O4/Ni O@CN-1 show excellent catalytic performance in OER.When the current density is 10 m A·cm-2,the overpotential is only 305.73 m V,and the maximum current density is as high as 124.7m A·cm-2.In the range of 1.3 V~1.7 V potential,after 1000 cyclic voltammetry scans with 50 m V·s-1,the linear sweep voltammetry curve(LSV)is similar to the initial curve,indicating that the catalyst has good stability.
Keywords/Search Tags:small molecule catalysis, carbon dioxide reduction, oxygen evolution reaction, bimetallic active site, carbon layer coating strategy
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