ZnO/Cu2O-decorated rGO: Heterojunction photoelectrode with improved solar water splitting performance. (19th July 2019)

• Record Type: Journal Article
• Authors: Hou, Tian-Feng; Shanmugasundaram, Arunkumar; Hassan, Mostafa Afifi; Johar, Muhammad Ali; Ryu, Sang-Wan; Lee, Dong-Weon
• Is Part Of: International journal of hydrogen energy. Volume 44:Number 35(2019)
• Page Start: 19177
• Page End: 19192
• Publication Date: 2019-07-19
• Subjects: ZnO/Cu2O heterostructure -- rGO -- Solar water splitting -- Enhanced PEC performance; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2018.05.105
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: In present work, we report a facile fabrication process to improve the photoelectrochemical (PEC) performance of ZnO-based photoelectrodes. In order to achieve that, the Cu2 O nanocubes are cathodic-deposited on the as-prepared ZnO nanorods. Then rGO nanosheets are electrodeposited on the ZnO/Cu2 O heterostructures. The fabricated photoelectrodes are systematically studied in detail by different characterization techniques such as powder X-ray diffraction, micro-Raman, X-ray photoelectron spectroscopy, ultraviolet diffused reflectance spectroscopy and photoluminescence spectroscopy analysis. Morphologies of the fabricated photoelectrodes are investigated through electron microscopy in scanning and transmission mode. To evaluate the PEC performance of the fabricated photoelectrodes, the line scan voltammetry (LSV) measurement is performed using a three-electrode system in 0.5-M Na2 SO4 electrolyte solution under stimulated light illumination at 100 mW/cm 2 from a 300-W Xenon Arc lamp coupled with an AM 1.5G filter using a three-electrode system. The photocurrent measurement demonstrates that the photoelectrodes based on ZnO/Cu2 O/rGO possess enhanced PEC performance compared to the pristine ZnO and ZnO/Cu2 O photoelectrodes. The photocurrent density of ZnO/Cu2 O/rGO-15 photoelectrode (10.11 mA/cm 2 ) is ∼9 and ∼3 times higher than the photoelectrodes based on pristine ZnO (1.06 mA/cm 2 ) and ZnO/Cu2 O (3.22 mA/cm 2 ). The enhanced PEC performance of ZnO/Cu2 O/rGO photoelectrode is attributed to the excellent light absorption properties of Cu2 O and excellent catalytic and charge transport properties of rGO. Experimental results reveal that the proposed functional nanomaterials have a great potential in water splitting applications. Graphical abstract: The improved PEC performance of the ZnO/Cu2 O/rGO hybrid photoelectrodes is attributed to (i) excellent crystalline nature of the as-prepared ZnO NRs and Cu2 O nanocubes, (ii) large light absorption property of the Cu2 O nanocubes, (iii) high electrical conduction effect and excellent charge transport property of the rGO nanosheets, (iv) electric effect induced by the heterojunction between the vertically aligned ZnO NRs, Cu2 O nanocubes and rGO nanosheets (Scheme 2) and (v) excellent electron acceptor and passivation layer of rGO. All these factors coupled together contribute to the excellent PEC performance of ZnO/Cu2 O/rGO hybrid based photoelectrodes.Image 1 Highlights: rGO-protected ZnO/Cu2 O heterojunction photoelectrodes for water splitting. Thickness of rGO on heterostructure controlled by electrochemical reduction time. Cu2 O significantly enhances the light absorption for ZnO/Cu2 O heterojunction. Super catalytic and charge transport properties of rGO improved the PEC performance.