Peroxymonosulfate activation on the S-scheme heterojunction Bi4O5I2/TiO2 photoanode of a photocatalytic fuel cell for degradation of tetracyclines with green power generation

Photocatalytic fuel cells (PFC) are green devices for simultaneous contaminant degradation and power generation. However, their performance is still limited due to the inefficient light capture and poor charge transfer at photoanodes. Here, a PFC has been successfully developed using a Bi 4 O 5 I 2 /TiO 2 nanotube arrays (NTAs) S-scheme heterojunction as the photoanode, incorporating peroxymonosulfate (PMS) as synergistic precursor of reactive oxygen species (ROS). A 17-fold increase in rate constant for the degradation of tetracycline (TC) and 6.6-fold increase in maximum power generation was attained in comparison with the TiO 2 /light PFC system. A systematic analysis elucidating PMS-mediated regulation of ROS generation and electron transfer was performed. The photocatalytic mechanism, dominated by non-radical 1 O 2 and photogenerated holes (h + ), led to a maximum photocurrent density (0.091 mA cm -2 ) and output power (0.99 mW cm -2 ). The current work demonstrates the great robustness of heterojunction-based PFC as new self-powered water decontamination systems. A self-powered PFC system using a Bi 4 O 5 I 2 /TiO 2 S-scheme photoanode and PMS enables efficient organic pollutant degradation and power generation, ROS generation, and light harvesting, offering a promising strategy for sustainable water purification. • A novel photocatalytic fuel cell (PFC) system for autonomous pollutant degradation • Bi 4 O 5 I 2 /TiO 2 nanotube arrays heterojunction as photoanode • Power generation ability of PFC system: P max of 0.99 mW cm -2 • PMS: crucial role in the generation of 1 O 2 and suppression of e - -h + recombination • Tetracycline degradation: 17-fold increase in k as compared to TiO 2 /light PFC