Favourable charge recombination kinetics are achieved to enhance solar hydrogen production utilizing reduced graphene oxide coated onto noble metal free CuBi2O4.

Harvesting clean energy from sunlight is a promising and desirable path to resolve the energy challenge through photoelectrochemical (PEC) water splitting. Herein, we report the design and synthesis of a stable hematite photoanode with sequential metal and nonmetal incorporation to resolve the limiting factors such as low carrier density and high charge recombination for its practical applications. Comprehensive morphological, optical, and photoelectrochemical properties of the doped hematite photoanodes are presented to understand the mechanisms by which the dopant incorporation impacts the photoelectrode performance. It is found that with controlled calcination temperature metal and nonmetal incorporation not only increases the carrier density but also facilitates faster charge transfer. The charge carrier density of the photoanode derived from Mott–Schottky plot shows an increase by an order of magnitude, i.e., from 5.1 × 1019 to 5.7 × 1020 cm–3, with dual modification. The dual modified hematite photoanode shows a photocurrent density of 2.56 mA/cm2 at 1.23 V vs RHE, which is ∼5-fold higher as compared to that of the bare hematite photoanode. We believe that the present method of designing and fabricating the hematite photoanode by sequential incorporation of metal and nonmetal will provide an economical and efficient strategy for better solar energy conversion.

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The growth of hierarchical morphologies of complex metal oxides directly onto the substrate is a challenging task. Here in we report, unique hollow-cuboidal MnCo2O4 (h-MCO) morphology that offers insights into...

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.

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.

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Rational design of complex spinel oxides directly onto the substrate as a highly stable electrocatalytic anode material for oxygen evolution reaction (OER) is a crucial step to replace a noble metal-based electrocatalyst. Herein, surfactant-free cuboidal MnCo2O4 (C-MCO) was synthesized in situ over FTO by a green and simple synthetic protocol. Stable and good ohmic contact between C-MCO and the substrate ensures efficient transfer of the charge carrier at their interface. Hexagonal boron nitride (h-BN) nanosheets coupled with C-MCO provides a surface for easy deposition of the co-catalyst, making active sites easily available and accessible for enhanced OER activity. The surface-modified C-MCO/h-BN electrode shows a Tafel slope value of 66 mV/dec with an overpotential of 240 mV at a current density of 10 mA/cm2. C-MCO/h-BN displays ∼2.8-fold enhancement in turnover frequency compared to its pristine counterpart, with a faradaic yield of 97%. This study can be used for large-scale clean energy production owing to its low-cost, efficient, eco-friendly, and long-term stability of the C-MCO/h-BN electrocatalyst.