Charge transfer and intrinsic electronic properties of rGO-WO3 nanostructures for efficient photoelectrochemical and photocatalytic applications

• Published in: Materials science in semiconductor processing Vol. 74; pp. 136 - 146
• Main Authors: Prabhu, S., Manikumar, S., Cindrella, L., Kwon, O.J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-02-2018
• Subjects: Hydrogen generation; Photocatalysis; Photoelectrochemical; rGO-WO3 nanostructures; Solar energy harvesting; Hydrogen generation; Solar energy harvesting; Photocatalysis; rGO-WO3 nanostructures; Photoelectrochemical
• ISSN: 1369-8001; 1873-4081
• DOI: 10.1016/j.mssp.2017.10.041

The synthesis of WO3 plate-like and rGO-WO3 nanostructured catalysts by a new and simple wet chemistry followed by thermal decomposition method is reported. The prepared catalysts were characterized by X-ray diffraction, Fourier transformed infrared spectroscopy, Raman spectroscopy, UV–vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning transmission electron microscopy techniques and Brunauer-Emmett-Teller surface area measurement. The photoelectrochemical properties and photocatalytic degradation of methylene blue by WO3 and rGO-WO3 nanostructured catalysts under simulated solar light, and visible light respectively was investigated. The incorporation of rGO in WO3 decreased the band gap energy from 2.54 to 2.45eV which also hindered the recombination rate of photogenerated electron-hole pairs and improved the electron transport properties. The plate-like structure of WO3 and rGO-WO3 nanostructured catalysts was observed from FESEM and TEM techniques. 5.3 and 4.2 folds higher photon-to-hydrogen conversion efficiency by rGO-WO3 photoanode at 0.08 and 0.30V respectively than WO3 photoanode was demonstrated. The photocatalytic activity of WO3 for the degradation of MB was also improved by forming a composite with rGO. The mechanism of the photoelectrochemical and photocatalytic process was discussed. This study provides a simple and scalable pathway to produce highly efficient rGO-WO3 nanostructured photocatalyst for harvesting solar energy efficiently.
Fig. (a) Transient photocurrent response and illustrations of (b) photoelectrochemical and (c) photocatalytic applications of rGO-WO3 nanostructured catalyst. [Display omitted]
•Highly efficient rGO-WO3 nanostructured catalysts prepared by a simple method.•Incorporation of rGO in WO3 suppressed the eˉ/h+ pair recombination.•5.3 fold higher H2 conversion efficiency by rGO-WO3 than WO3.•Efficient photocatalytic degradation of MB by rGO-WO3.