S-scheme 3D/2D NiCo2O4@g-C3N4 hybridized system for boosting hydrogen production from water splitting

Photocatalytic H2 production from water splitting is always considered as a renewable and sustainable process for converting solar energy into chemical energy. In this study, a 3D/2D NiCo2O4/g-C3N4 (NCO/g-CN) S-scheme heterojunction is constructed to boost H2 evolution under visible light irradiation. After adding NiCo2O4 nanoballs, the H2 generation has been significantly enhanced by effectively adjusting the moving routes of photoinduced electrons and holes and the maximum H2 generation reaches 21.2 μmol∙h−1 of H2 yield over 3%NCO/g-CN, which is 4.16 times higher than that of the pure g-C3N4 (5.1 μmol∙h−1). The above data can show that the g-C3N4 modified 3D NiCo2O4 nanoballs performs well in hydrogen production and the photocatalytic activity is significantly improved. To further understand the reason for boosted photochemical catalysis activities, the physical as well as chemical properties of the NCO/g-CN are explored. The results display that the construction of 3D/2D S-scheme heterojunction between 3D NiCo2O4 and 2D g-C3N4 extends the range of visible light, obtains excellent photo redox ability, and inhibits charge recombination efficiency. Such a novel photocatalyst responding to visible light provides a new choice for efficient H2 production by utilizing the solar energy.