Synergistic role of hydrogen treatment and heterojunction in H-WO3-x/TiO2-x NT/Ti foil-based photoanodes for photoelectrochemical wastewater detoxification and antibacterial activity

• Published in: Chemosphere (Oxford) 2023-03, Vol.318, p.137973-137973, Article 137973
• Main Authors: Mahadik, Mahadeo A., Hwang, In-Seon, Chae, Weon-Sik, Lee, Hyun Hwi, Choi, Sun Hee, Cho, Min, Jang, J.S.
• Format: Article
• Language: English
• Subjects: Heterojunction; Hydrogen treatment; Microwave synthesis; Oxygen vacancy; Wastewater detoxification
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2023.137973

The process of photoelectrochemical wastewater detoxification is limited by significant charge recombination, which is difficult to suppress with efficient single-material photoanodes. We demonstrated the effectiveness of hydrogen treatment in evaluating charge separation properties in WO3-x/TiO2-x NT/Ti foil heterojunction photoanodes. The influence of varying hydrogen annealing (200–400 °C) on the structural and photoelectrochemical properties of WO3/TiO2 NS/NT heterojunction is studied systematically. Additionally, after hydrogen treatment of pristine WO3/TiO2 NT/Ti foil photoanodes, substoichiometric H-WO3-x/TiO2-x NT-300 achieved the 1.21 mA/cm2 photocurrent density, which is 8.06 and 3.27 times than TiO2 NT and WO3/TiO2 NT. The hydrogen-treated H-WO3-x/TiO2-x NT-300 electrode exhibits 3 times greater bulk efficiencies than the WO3/TiO2 NT electrode due to the production of oxygen vacancies at the interface. Additionally, optimum H-WO3-x/TiO2-x NS/NT-300 photoanode exhibited 93.8% E. coli and 99.8% BPA decomposition efficiencies. The present work shows the effectiveness of microwave-assisted H-WO3-x/TiO2-x NT heterojunction photoanodes for organic decomposition and antibacterial activity in a neutral environment without surface-loaded co-catalysts. Here, for the first time, we develop H-WO3-x/TiO2-x NT/Ti foil-based photoanodes by a simple microwave and anodization process. The optimum H-WO3-x/TiO2-x NT-300 exhibited 93.8% and 99.8% E. coli and BPA degradation in 180 min. Additionally, optimum photoanode achieved 8.06 times higher photocurrent density (1.21 mA/cm2) than TiO2 NT. [Display omitted] •H-WO3-x/TiO2-x NT/Ti was developed via a simple surfactant-free microwave-process.•PEC performance is enhanced by cooperation of defects and TiO2-x transport channels.•H-WO3-x/TiO2-x NT-300 displayed 8 times higher photocurrent density than TiO2 NT.•93.8% E. coli and 99.8% BPA decomposition efficiency within 180 min.•The charge transfer mechanism in H-WO3-x/TiO2-x NT-300 during PEC is well proposed.