Tuning Mo cations dissolution and surface reconstruction of CoMoO4 for efficient oxygen evolution reaction

Abstract

Structural distortion enables modulating surface reconstruction of transition metal oxides by manipulating cation dissolution for oxygen evolution reaction (OER), while revealing reconstruction mechanism is stuck by the demand to precisely regulate exact sites of these structural distortions and further make a robust correlation between surface reconstruction and OER performance. In this work, controllable Mo dissolution in CoMoO4 is adjusted by the structural distortion level of MoO4 tetrahedrons with different annealing temperatures. The structural distortion level of MoO4 tetrahedrons is positively correlated with annealing temperatures and spontaneous Mo cations dissolution in alkaline solution. The moderate amount of spontaneous Mo cations dissolution, in accompany with maximum dissolution amount of Mo cations derived from potential, could expose more Co sites to reconstruct into active species CoOOH at a lower potential, resulting in more catalytically active sites whose overpotential at 100 mA cm−2 with 346 mV and Tafel slope of 92.22 mV dec−1. This work indicates the importance of controlled cation dissolution in modulating the kinetics of surface reconstruction and OER performance of electrocatalysts.