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

Abstract

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 Bi4O5I2/TiO2 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 TiO2/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 1O2 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.