Evaluating the Fe-doping effect on intermediate adsorption modulation for Co-based vanadates toward separation of hydrogen from water electrolysis

Abstract

The optimization of intermediate adsorption is pivotal for enhancing the efficacy of catalysts in oxygen evolution reaction (OER). However, many Co-based catalysts exhibit excessive binding energy toward intermediates, thereby restricting the desorption process. To address this issue, we utilized the Co-based vanadates (CoV) as a model and observed that the incorporation of Fe can effectively mitigate the substantial accumulation of intermediates around the catalysts, achieving a balance between the adsorption and desorption. It can be attributed to the Fe-doping, which modulated the electronic structure of CoV, subsequently increasing the catalytic sites and intrinsic activity. As a result, the CoV-Fe exhibited a low overpotential of 260 mV at 20 mA cm−2, which decreased by 82 mV compared to pristine CoV. Besides, the electrolyzer based on CoV-Fe maintained a low cell of 1.46 V for water splitting and held a considerable attenuation of 4.49 % after 200 h of long-term operation.