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.