Synthesizing And Electrocatalytic Performance Of Heteroatomdoped Carbon Material With Hierarchically Porosity

The sustainable and harmonious development among economy,nature and humans is a severe problemto solve in mordern society.Fossil fuels containing oil,coal,natural gas and so on,are the main energy sources,whose use have caused more and more pollution and damage to our living environment.Hydrogen energy and fuel cells are expected to replace fossil fuels as the main energy in the future for theiradvantages.However,hydrogen evolution reaction(HER)in electrolysis of water and oxygen reduction reaction(ORR)in fuel cells both need the assistance of catalysts.To date,the best catalysts for HER and ORR are Pt-based materials.Unfortunately,the scarcity and high cost of Pt impede heavily the large-scale commercialization.So,it is of great significanceto explore and find the catalysts with high efficiency and low price.Heteroatomdoped carbon materialsare expected to replace the the Pt-based catalysts,for their high efficiency and low price.Here,Co-N-GA and Co/N/GA-900 are prepared by the combination of two different MOFs and graphene,which both are cobalt-embedded in nitrogen doped carbon materials and prepared by hydrothermally assembled method and high temperature pyrolysis.In the experiment,the functionality and porosity structure of catalyst can be controlled by adjusting the ratio of precursors and temperature of pyrolysis.The two kinds of the catalysts were characterized by a hand of characterization methods,containing scanning electron microscopy(SEM)and transmission electron microscopy(TEM)for morphology;X-ray photoelectron spectroscopy(XPS)and X-ray diffraction(XRD)for surfacechemicalpropertiesanalysis;nitrogen adsorption and desorption isotherms and Raman spectra forporestructureandthedegreeofgraphitization,respectively;and a series of electrochemical test are operated to evaluate the catalyticperformance of HER and ORR.For the catalyticperformance of HER,LSV and Tafel plots are used to evaluate the catalyticactivity and i-t coupled with the comparison of the LSV before and after 5000 CV cycles to evaluate the stability;For the catalyticperformance of ORR,CV,LSV and i-t are operated to evaluate the catalytic activity,stability for ORR and the immunity to methanol.It is found that Co-N-GA and Co/N/GA-900 both have the better catalytic activity and stability for HER and ORR.