摘要
Metal-free carbon-based catalysts exhibit diverse electrocatalytic performances in CO_(2) reduction reaction(CO_(2)RR),but the attributions and contributions of active sites are still confusing to date.Herein,the hierarchical carbon nanocages(hCNC)doped with different heteroatoms(B,N,P,S)are prepared to examine the impact of dopants on the competitive CO_(2)RR and hydrogen evolution reaction(HER).The hCNC and P-doped hCNC show little CO_(2)RR activity,B-and S-doped hCNC show weak CO_(2)RR activity,while N-doped hCNC presents high CO_(2)RR activity.The CO Faradaic efficiency(FECO)of N-containing hCNC increases almost linearly with increasing the N content,even with the co-existing B or P.S and SN-doped hCNC more facilitate the HER.16 doping configurations are constructed,and up to 53 sites are examined CO_(2) H2O H2 CO*H*COOH*CO for the electrochemical activities with a constant potential modelling method.The pyridinic-N(N^(*))is the best active site for CO_(2)RR to CO,while CBO_(2)H_(2)-1(αC^(*)),CBO_(2)H_(2)-2(γC^(*)),NO-1(βC^(*)),PO_(2)H-3(αC^(*))and SO_(3)H-3(δC^(*))are active for HER.The optimized FECO achieves 83.6%for N-doped hCNC with 9.54 at.%nitrogen,and S-doped hCNC reaches ca.30 mA·cm^(-2) current density for HER.This study unveils the structure-performance correlation of heteroatom-doped hCNC,which is conducive to the rational design of advanced metal-free carbon-based catalysts.
基金
This work was jointly supported by the National Key Research and Development Program of China(No.2021YFA1500900)
the National Natural Science Foundation of China(No.52071174)
the Natural Science Foundation of Jiangsu Province,Major Project(No.BK20212005)。
