Step-Scheme Heterojunction between CdS Nanowires and Facet-Selective Assembly of MnO<sub><i>x</i></sub>-BiVO<sub>4</sub> for an Efficient Visible-Light-Driven Overall Water Splitting
Devipriya Gogoi, Adit Kumar Shah, Ponnala Rambabu, Mohammad Qureshi, Animes Kumar Golder, Nageswara Rao Peela
Abstract
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/MnOx-BiVO4 photocatalyst was synthesized by spatial deposition of MnOx and one-dimensional (1D) CdS nanowires on a three-dimensional (3D) decahedron BiVO4 surface. The photocatalytic activity of CdS/MnOx-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/MnOx-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 (MnOx and Pt) with the photocatalysts (BiVO4 and CdS) in the 5CdS/MnOx-BiVO4 heterojunction. The significance of the presence of MnOx and Pt cocatalysts on the selective facets of BiVO4 for efficient overall water splitting reaction is highlighted in this work.