Cobalt as a sacrificial metal to increase the photoelectrochemical stability of CuBi2O4 films for water splitting. (29th January 2023)

• Record Type: Journal Article
• Authors: Bruziquesi, Carlos G.O.; Stolzemburg, Matheus C.P.; de Souza, Rafael R.; Rodriguez, Mariandry; Rocco, Maria L.; Salomão, Pedro E.A.; Nogueira, André E.; López-Cabaña, Zoraya E.; Pereira, Márcio C.; Silva, Adilson C.
• Is Part Of: International journal of hydrogen energy. Volume 48:Number 9(2023)
• Page Start: 3456
• Page End: 3465
• Publication Date: 2023-01-29
• Subjects: Water splitting -- Photocathode -- Photocorrosion -- Photoelectrochemical cell -- Hydrogen -- Bismuth copper oxide; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.10.195
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: CuBi2 O4 is an excellent photocathode candidate in water-splitting photoelectrochemical cells. However, its poor photoelectrochemical stability caused by the reduction of Cu 2+ to Cu metal limits its use. Here, we show a strategy to decrease the reduction of Cu 2+ to Cu using cobalt as a sacrificial metal. Co-doped CuBi2 O4 films were prepared by spray pyrolysis using Co 2+ salt as the precursor. Co 2+ ions replace Cu 2+ in the CuBi2 O4 structure, and subsequent heat treatment at 500 °C leads to partial oxidation of Co 2+ to Co 3+ . As the reduction potential of Co 3+ /Co 2+ is higher than that of Cu 2+ /Cu, Cu 2+ reduction can be minimized. Comparatively, about 72% of the photocurrent produced by the CuBi2 O4 film is lost in the first few minutes of illumination. In the Co-doped CuBi2 O4 film, the photocurrent drops by less than 7%. Thus, the Co-doping can increase the CuBi2 O4 photostability and be helpful for the fabrication of more stable photocathodes. Graphical abstract: Image 1 Highlights: Co-doped CuBi2 O4 film was synthesized by a simple spray pyrolysis method. Co 2+ and Co 3+ ions occupy Cu sites in the CuBi2 O4 structure. Cobalt acts as a sacrificial metal to inhibit the reduction of Cu 2+ to Cu metal. Co-doped CuBi2 O4 photocathodes are 90% more resistant to photocorrosion than CBO film. Co-doping is a promising method to make CuBi2 O4 films more stable for water splitting.