Step-Scheme Heterojunction between CdS Nanowires and Facet-Selective Assembly of MnOx-BiVO4 for an Efficient Visible-Light-Driven Overall Water Splitting

The spatial separation and transport of photogenerated charge carriers is crucial in building an efficient photocatalyst for solar energy conversion into chemical energy. A step-scheme CdS/MnO_x-BiVO₄ photocatalyst was synthesized by spatial deposition of MnO_x and one-dimensional (1D) CdS nanowires on a three-dimensional (3D) decahedron BiVO₄ surface. The photocatalytic activity of CdS/MnO_x-BiVO₄ for the overall water-splitting reaction was investigated without sacrificial reagent under visible light irradiation. The synthesized photocatalysts were thoroughly analyzed using high-end characterization techniques. The 5CdS/MnO_x-BiVO₄ exhibited the highest H₂ and O₂ production rates of 1.01 and 0.51 mmol g^-1 h^-1, respectively, with an apparent quantum yield of 11.3% in the absence of any sacrificial reagent. The excellent photoactivity is due to the presence of oxygen vacancies along with effective charge separation/transfer properties and strong interaction of cocatalysts (MnO_x and Pt) with the photocatalysts (BiVO₄ and CdS) in the 5CdS/MnO_x-BiVO₄ heterojunction. The significance of the presence of MnO_x and Pt cocatalysts on the selective facets of BiVO₄ for efficient overall water splitting reaction is highlighted in this work.