Carbon supported NiCo alloy catalyst with face-to-face encapsulated structure for electrocatalytic hydrogen evolution

The exploitation of cost-effective catalysts for hydrogen evolution reaction (HER) remains a major challenge for electrochemical water decomposition to store clean energy. Herein, an efficient non-precious metal catalyst is developed by encapsulating NiCo alloy nanosheets with carbon nanosheets. The optimized NiCo/C catalyst achieves overpotentials of 21 mV at a current density of 10 mA cm⁻² and 105 mV at 50 mA cm⁻². These values are significantly lower than those of commercial Pt/C, which are 42 mV and 112 mV at the same current densities, respectively. Additionally, the NiCo/C catalyst exhibits long-term stability, maintaining its performance for 24 h at a current density of 10 mA cm⁻². The high HER active and stability in alkaline medium can be attributed to the synergistic effect of surface chemical state tuning of Co and Ni in the NiCo alloy and face-to-face encapsulated structure because it effectively facilitates electron transfer, accelerates reaction kinetics, and avoids corrosion of the NiCo alloy. This work provides a possibility for efficient and low-cost non-precious catalysts needed for green hydrogen production.