Tuning the electronic structures of cobalt-molybdenum bimetallic carbides to boost the hydrogen oxidation reaction in alkaline medium

Due to the trend of using hydroxide exchange membrane fuel cells (HEMFCs) to replace the proton exchange membrane fuel cells (PEMFCs) for realizing the application of non-precious metal electrocatalysts in cathodic oxygen reduction reaction (ORR), it becomes increasingly urgent to develop the efficient and durable nonprecious metal electrocatalysts for hydrogen oxidation reaction (HOR) in alkaline medium. The Co-Mo bimetallic carbides (CoxMoyC) are proposed to be used as non-precious metal electrocatalysts for alkaline HOR to boost the catalytic activity by tuning the electronic structures and maintaining the optimal adsorption of Hads and OHads at the same time. In this report, we design and fabricate three configurations of Co-Mo bimetallic carbides to investigate the relationship between their catalytic performance and lattice expanding degree. Among them, Co3Mo3C nanorods supported on cobalt foam (Co3Mo3C NR/CF) exhibit a current density of 5.6 mA cm-2 at 0.10 V vs. RHE toward HOR and exchange current density (j0) of 1.84 mA cm-2. Besides, Co3Mo3C NR/CF electrocatalysts can maintain the catalytic current density over 2.2 mA cm-2 at 0.05 V vs. RHE for over 12 h. Furthermore, the density functional theory (DFT) calculations reveal the boosting catalytic activities on Co3Mo3C originate from the suitable tuning electronic structures.