Construction of triple heterogeneous interfaces optimizing electronic structure with B-doped amorphous CoP deposited on crystalline Cu2S/Ni3S2 nanosheets to enhance water electrolysis

Designing non-precious-metal catalysts with performance matching that of precious-metal catalysts is crucial to the development of clean hydrogen energy. Herein, construction heterostructures and heteroatom doping strategies have been employed to construct an amorphous CoPB deposited on a crystalline Cu2S/Ni3S2 nanosheet (CoPB@Cu2S/Ni3S2) non-precious-metal electrocatalyst for water electrolysis. The introduction of Cu2+ successfully gave rise to an Ni3S2/Cu2S crystal–crystal heterostructure, on which the coating of the amorphous CoPB layer finally achieves a triple heterostructure by an electroless plating technique. The optimized electronic structure and geometry allow the CoPB@Cu2S/Ni3S2 catalyst to show a competitive catalytic performance, which requires just 25 mV of overpotential for the HER and 247 mV for the OER to achieve a current density of 10 mA cm−2. When loaded into an AEM water electrolyzer, the CoPB@Cu2S/Ni3S2‖CoPB@Cu2S/Ni3S2 cell just requires 1.84 V cell voltage to offer a large current density of 2000 mA cm−2, running for more than 1000 h without significant degradation in performance. This work demonstrates the benefit of the integration of the heterostructures and heteroatom doping strategies to prepare catalysts and provides a scientific basis for the development of high-performance non-precious-metal water electrolysis catalysts.