Construction of Ni/N Co-doped Self-supported Carbon Foam Electrodes for Electrocatalytic CO2 Reduction
A series of nickel/nitrogen co-doped self-supported carbon foam electrodes were prepared by impregna-tion,curing and carbonization using asphalt as the carbon source and polyurethane foam as the template,and then characterized by scanning electron microscopy,transmission electron microscopy,N2 adsorption-desorption analysis,Raman spectroscopy and X-ray photoelectron spectroscopy.The results show that the prepared carbon foam electrodes possess a three-dimensional macroporous skeleton structure.Moreover,their surface is abundant in defect sites and Ni-N coordination structures.The content of N species can be regulated by varying the carbonization temperature,thereby enabling the regulation of the content of Ni-Nx active sites.The carbon foam electrodes were directly used as a self-supported electrode for the electroreduction of CO2,and a syngas with a stable and controllable H2/CO molar ratio could be obtained.The H2/CO molar ratio can be tuned from 1/2 to 2/1 within the potential window of-0.9～-1.3 V(vs.RHE).In addition,the current density of the carbon foam electrode obtained at the carbonization temperature of 900 ℃ can be maintained at 5.7 mA/cm2 after a sustained reaction for 10 h,and the H 2/CO molar ratio can be maintained at about 1/1.
Electrocatalytic CO2 reductionSelf-supported electrodeSyngasCarbon foam
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