Exploring the Capability of Cu-MoS 2 Catalysts for Use in Electrocatalytic Overall Water Splitting.

Herein, we prepare MoS 2 and Cu-MoS 2 catalysts using the solvothermal method, a widely accepted technique for electrocatalytic overall water-splitting applications. TEM and SEM images, standard tools in materials science, provide a clear view of the morphology of Cu-MoS 2 . HRTEM analysis, a high-resolution imaging technique, confirms the lattice spacing, lattice plane, and crystal structure of Cu-MoS 2 . HAADF and corresponding color mapping and advanced imaging techniques reveal the existence of the Cu-doping, Mo, and S elements in Cu-MoS 2 . Notably, Cu plays a crucial role in improving the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) of the Cu-MoS 2 catalyst as compared with the MoS 2 catalyst. In addition, the Cu-MoS 2 catalyst demonstrates significantly lower overpotential (167.7 mV and 290 mV) and Tafel slopes (121.5 mV dec -1 and 101.5 mV dec -1 ), standing at -10 mA cm -2 and 10 mA cm -2 for HER and OER, respectively, compared to the MoS 2 catalyst. Additionally, the Cu-MoS 2 catalyst displays outstanding stability for 12 h at -10 mA cm -2 of HER and 12 h at 10 mA cm -2 of OER using chronopotentiaometry. Interestingly, the Cu-MoS 2 ‖Cu-MoS 2 cell displays a lower cell potential of 1.69 V compared with the MoS 2 ‖MoS 2 cell of 1.81 V during overall water splitting. Moreover, the Cu-MoS 2 ‖Cu-MoS 2 cell shows excellent stability when using chronopotentiaometry for 18 h at 10 mA cm -2 .