RESUMO
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.
RESUMO
The growth of hierarchical morphologies of complex metal oxides directly on the substrate is a challenging task. Herein we report a unique hollow-cuboidal MnCo2O4 (h-MCO) morphology that offers insights into the efficient charge-transfer and surface kinetics for the oxygen evolution reaction. h-MCO coupled nickel phosphate under alkaline conditions outperforms the benchmark RuO2.
RESUMO
Overlayer passivation minimizes surface defects and arrests the back transfer of electrons for an enhanced charge extraction. Surface passivation of ZnFe2O4 using alumina yields enhanced charge carrier density from 8.43 × 1020 cm-3 to 18.83 × 1020 cm-3 giving a record efficiency in this class of compounds.
