Synergistic Co–P bonding effect on hydrogen evolution reaction activity and supercapacitor applications of CoMoP material

Due to the synergistic effect between transition metals and hetero-atoms, transition metal-phosphide-based composites have been used as electrode materials for electrocatalytic hydrogen evolution reactions (HER) and supercapacitors, but their ideal performance has yet to be achieved. Herein, the binary transition metal phosphides, CoMoP and NiMoP, were grown on Ni-foam using a two-step hydrothermal approach and phosphorus deposition in a tube furnace. Both the CoMoP and NiMoP materials showed promising HER activity, displaying an overpotential of 137 mV and 144 mV @10 mA/cm2, respectively. The theoretical studies demonstrated that the ΔGH∗ on CoMoP (−0.28 eV) was closer to zero than on NiMoP (−0.34 eV), due to the synergistic Co–P bonding, making it more accessible for H-adsorption, thereby endowing HER. In addition, the CoMoP and NiMoP materials exhibited 3507 F/g and 930 F/g energy storage capacities, respectively. Moreover, both samples had close to 100% Coulombic efficiency and about 50% capacitance retention. Based on these findings, it looks like CoMoP could be good for both the HER and supercapacitor electrodes.