Influence of ultrafast microwave deposition on morphology and growth mechanism of WO3 nanosheet photoanode for efficient bacterial inactivation and decomposition of organic pollutants

We report the ultrafast synthesis of WO3 nanosheet array photoanode on fluorine-doped tin oxide-coated glass without a seed layer by microwave-assisted deposition route. The ultrafast microwave-assisted synthesis at various microwave deposition cycles resulted in tailored WO3 morphologies with a monoclinic structure. The photoanode growth mechanism and effect of morphology tuning on the photoelectrochemical activities of WO3 photoanodes were studied in detail. Under one sun irradiation, the microwave-assisted WO3 photoanode prepared at four cycles (WO3-4 MW) exhibited a photocurrent density of 1.1 mA/cm2 at 1.0 V versus Ag/AgCl, whereas the WO3 photoanode prepared at two cycles (WO3-2 MW) achieved 0.68 mA/cm2. Further, hydrogen treatment of optimum WO3-4 MW photoanodes at 300 °C, 20 min and exhibited a high photoelectrochemical (PEC) degradation efficiency of Orange II dye (∼99 %/180 min) and BPA (98.5 % in 30 min). Additionally, ∼97 % E. Coli bacterial PEC inactivation was achieved within 120 min over H2-WO3-4 MW under one sun illumination irradiation. Also, plausible charge recombination/separation processes in microwave-assisted WO3/FTO and H2-WO3-4 MW photoanodes were also reported. [Display omitted] •The WO3-4 MW was developed via a simple surfactant-free microwave- process.•A growth mechanism is proposed for WO3-4 MW photoanodes.•WO3-4 MW achieved two times photocurrent 1. 1 mA/cm2 than WO3-2 MW.•H2-WO3-4 MW exhibited 97 %, 98.5 % decomposition efficiency for E. coli - and -BPA pollutants.•The charge transfer processes in H2-WO3-4 MW photoanodes are well proposed.