Tuning the d-Band Center of Co3O4 via Octahedral and Tetrahedral Codoping for Oxygen Evolution Reaction

Promoting catalytic performance caused by d-band center modulation has been proven to play a crucial role in designing highly active spinel-based catalysts. Herein, two different geometrical configurations were adopted to modify the d-band center of Co3O4, in which monotonous replacement of octahedral cobalt sites by Al and Ga and dual regulation of octahedral and tetrahedral cobalt sites through the introduction of Fe, Ni, and In were accomplished, respectively. A volcanic diagram between the d-band center and the potential-determining step (PDS) energy barriers was determined through theoretical prediction consistent with the experimental results of catalytic performance. This work revealed that the conventionally perceived regulation of the octahedral configuration in Co3O4 was insufficient to trigger an enhancement of performance. Still, the d-band center shift of Co sites caused by octahedral and tetrahedral collaborative modulation significantly decreased the energy barrier of the oxygen evolution reaction (OER).