Amorphous Boride/Selenide Heterojunction Coupling Light-Response Effects for Large Current Water Splitting

Designing heterojunction photo/electrocatalysts to synergistically achieve a flexible two-phase composition and highly stable interface is urgently desired but continues to be a major obstacle. In this work, we report an amorphous/crystalline boride-selenide heterojunction Ni–W–B/WSe2 catalyst via a mild electroless plating, which served as a bifunctional catalyst for photoassisted water electrolysis. Under simulating sunlight, the Ni–W–B/WSe2 catalyst can achieve a current density of 100 mA cm–2 at only 67 mV for hydrogen evolution reaction (HER) and 265 mV for oxygen evolution reaction (OER). Compared with the situation without light, its electrocatalytic performances of HER, OER, and overall water splitting improved by 10–15% at 10 mA cm–2. The enhancement results of the external physical field came from the light-response effects caused by construction of the boride/selenide heterojunction. Moreover, it can sustain operation at a substantial 200 mA cm–2 for more than 400 h without any discernible decline in performance in 1.0 M KOH solution. These discoveries may raise an essential and comprehensive understanding of multiple effects under the photoassisted electrocatalysis reactions, thus reducing the dependence on electric energy and the conversion efficiency of primary energy.