High-efficiency bifunctional M-doped NiSe/Ni3Se2 (M=Co, Fe, Cd) electrocatalysts for seawater and urea oxidation

Electrocatalytic seawater splitting for generating H 2 has become one of the most promising methods. This study prepared M-NiSe/Ni 3 Se 2 (M = Co, Fe, Cd) electrocatalysts through a one-step hydrothermal selenification reaction. In alkaline seawater, the Co–NiSe/Ni 3 Se 2 electrode requires overpotentials of 273, 369, and 431 mV to drive current densities of 10, 50, and 100 mA cm −2 for oxygen evolution reaction (OER) process, respectively. Moreover, the Co–NiSe/Ni 3 Se 2 electrocatalyst needs only potential of 1.395 V to drive a current density of 10 mA cm −2 in the urea oxidation reaction (UOR) process. According to density functional theory result, the synergistic effect between the large H 2 O adsorption capacity of Co–NiSe and the superior electrical conductivity of Ni 3 Se 2 is a key factor for contributing to the superior performance of the Co–NiSe/Ni 3 Se 2 catalyst. This study conducted systematic doping comparison experiments on the NiSe/Ni 3 Se 2 system, providing authentic and reliable experimental support for the design of selenide electrocatalysts.