Chen Xin, Luo Liang, Zhang Yizhen
Center for Computational Chemistry and Molecular Simulation, College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China.
Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China.
Langmuir. 2021 May 25;37(20):6330-6336. doi: 10.1021/acs.langmuir.1c00857. Epub 2021 May 14.
Since the active site of spinel NiCoO as an oxygen reduction reaction (ORR) catalyst is under debate, the optimal active sites of NiCoO are identified by investigating the catalytic properties of two models of NiCoO. The results indicate that the ORR activity of five studied active sites of isolated NiCoO is primarily limited by excessively binding of *OH, and the Co and Ni active sites of Co[CoNi]O are identified as the optimal catalytic sites with overpotentials of 0.69 and 0.76 V, respectively. Moreover, for the investigation of the support effect, the isolated NiCoO is supported on pristine and N-doped carbon nanotube (CNT and NCNT). Encouragingly, the ORR activity of Co and Ni active sites is improved after NiCoO is supported on CNT and NCNT due to the weakened binding of *OH. When NiCoO is supported on NCNT via the Co ion, the rate-determining step of ORR catalyzed by Co and Ni sites is altered. Moreover, this Co site exhibits the highest ORR activity and displays an overpotential of only 0.45 V. Therefore, the support effect can improve the catalytic activity as well as change the mechanism of ORR. This study presents more insights into the active sites and ORR activity of NiCoO.
