Photoelectrochemical performance of a spin coated TiO2 protected BiVO4-Cu2O thin film tandem cell for unassisted solar water splitting

• Published in: RSC advances Vol. 12; no. 48; pp. 31380 - 31391
• Main Authors: Sitaaraman, S R, Andrews, Nirmala Grace, Sellappan, Raja
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 02.11.2022; The Royal Society of Chemistry
• Subjects: Bismuth oxides; Chemistry; Copper oxides; Current density; Molybdenum disulfide; Photocathodes; Spin coating; Stability; Thin films; Titanium dioxide; Vanadates; Water splitting; Xenon lamps
• ISSN: 2046-2069
• DOI: 10.1039/d2ra05774c

A tandem cell consisting of a Mo-BiVO4/TiO2/FeOOH photoanode–Cu2O/TiO2/MoS2 photocathode was prepared for unassisted solar water splitting. The protective TiO2 layer was prepared by a cost-effective spin coating technique. The individual Mo-BiVO4/TiO2/FeOOH photoanode and the Cu2O/TiO2/MoS2 photocathode yielded a current density of ∼0.81 mA cm−2 at 1.23 V vs. RHE and ∼−1.88 mA cm−2 at 0 V vs. RHE, respectively under 100 mW cm−2 xenon lamp illumination. From the individual photoelectrochemical analysis, we identify the operating points of the tandem cell as 0.66 V vs. RHE and 0.124 mA cm−2. The positive current density from the operating points proves the possibility of non-zero operation of the tandem cell. Finally, a two-electrode Mo-BiVO4/TiO2/FeOOH-Cu2O/TiO2/MoS2 tandem cell was constructed and analysed for unassisted operation. The obtained unassisted current density of the tandem cell was ∼65.3 μA cm−2 with better stability compared to the bare BiVO4-Cu2O tandem cell. The results prove that the spin coated TiO2 protective layer can be a viable approach to protect the photoelectrodes from photocorrosion with better stability and enhanced photoelectrochemical (PEC) performance.