CuO photoelectrodes synthesized by the sol–gel method for water splitting

• Published in: Journal of sol-gel science and technology 2019-01, Vol.89 (1), p.255-263
• Main Authors: Toupin, J., Strubb, H., Kressman, S., Artero, V., Krins, N., Laberty-Robert, Ch
• Format: Article
• Language: English
• Subjects: Catalysis; Ceramics; Chemical Sciences; Chemistry and Materials Science; Composites; Deposition; Dip coatings; Glass; Hydrogen evolution; Immersion coating; Inorganic Chemistry; Low cost; Material chemistry; Materials Science; Nanotechnology; Natural Materials; Optical and Electronic Materials; Original Paper: Sol-gel and hybrid materials for catalytic; Photocathodes; Photoelectric effect; Photoelectric emission; photoelectrochemical and sensor applications; Protective coatings; Sol-gel processes; Stability; Stoichiometry; Thickness; Thin films; Titanium dioxide; Water splitting
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-018-4896-3

CuO is an attractive photocatalytic material for water splitting due to its high earth abundance and low cost. In this paper, we report the deposition of CuO thin films by sol–gel dip-coating process. Sol deposition has attractive advantages including low-cost solution processing and uniform film formation over large areas with a fairly good control of the film stoichiometry and thickness. Pure CuO phase was obtained for calcination temperatures higher than 360 °C in air. The CuO photocurrents for hydrogen evolution depend on the crystallinity and the microstructure of the film. Values of −0.94 mA cm −2 at pH = 8 and 0 V vs. RHE were achieved for CuO photoelectrodes annealed at 400 °C under air. More interestingly, the stability of the photoelectrode was enhanced upon the sol–gel deposition of a TiO 2 protective layer. In this all sol–gel CuO/TiO 2 photocathode, a photocurrent of −0.5 mA cm −2 is achieved at pH = 7 and 0 V vs. RHE with a stability of ~100% over 600 s. Highlights Sol–gel-based CuO photoelectrode has values of −0.94 mA cm −2 at pH = 8 and 0 V vs. RHE. CuO/TiO 2 photoelectrodes have been synthesized by the sol–gel chemistry coupled with dip-coating. These photoelectrodes exhibit −0.5 mA cm −2 at pH = 7 and 0 V vs. RHE. These photoelectrodes are 100% stable over 600 s.