In-situ fabrication of AgI-BiOI nanoflake arrays film photoelectrode for efficient wastewater treatment, electricity production and enhanced recovery of copper in photocatalytic fuel cell

Abstract In this study, a novel hybrid AgI nanoparticles-BiOI nanoflake arrays (AgI-BiOINFs) film electrode was in situ synthesized via a facile and controllable approach and proposed as a phonoanode for the photocatalytic fuel cell (PFC) for the first time. The structure and optical properties of AgI-BiOINFs film were characterized by means of X-ray diffraction (XRD), scanning electronic microscopy (SEM), UV–vis diffuse reflectance spectroscopy (UV–vis DRS) and photoluminescence (PL) while the photoelectrochemical activity of AgI-BiOINFs film electrode was characterized by the photocurrent-time transient response and electrochemical impedance spectroscopy (EIS). The photocatalytic activity of AgI-BiOINFs film was evaluated in the term of the electricity generation efficiency and degradation efficiency of formic acid. The open-circuit voltage ( V oc ), photocurrent density ( J sc ) and the maximum power density of AgI-BiOINFs film in PFC were 0.724 V, 90.02 μA cm −2 and 16.25 μW cm −2 , respectively, exhibiting a much improvement over BiOINFs film. Similarly, the photocatalytic degradation efficiency of formic acid by AgI-BiOINFs film was significantly higher than that of BiOINFs film. Furthermore, the AgI-BiOINFs electrode has excellent stability towards formic acid degradation and electricity production over four operation cycles. The electricity generated by the PFC was applied on AgI-BiOINFs-Ti photoelectrocatalytic (PEC) reactor to enhance the degradation of organic compounds and recovery of copper. The mechanism of enhanced photocatalytic performance in PEC system was further explored by reactive species trapping and ESR experiments.