A dual-biomimetic photocatalytic fuel cell for efficient electricity generation from degradation of refractory organic pollutants

Abstract

Energy recovery from wastewater treatment is attracting tremendous research interests since the environmental and energy issues can be simultaneously addressed. Photocatalytic fuel cell (PFC) provides a sustainable way for water purification and electricity generation, but its performance has been restricted by the poor mass and charge transfer. Herein, we demonstrated an integrated PFC platform by mimicking the metabolic processes in human body. Inspired by the purification of metabolites in the microstructure of liver lobules, flow-through TiO2 photoanode with numerous microchannels was developed. Compared to traditional PFC with planar photoanode, the biomimetic microflow PFC exhibited 3 to 5-fold enhancements in the removal efficiencies of various organic pollutants, including perfluorooctanoic acid, 4-chlorophenol, bisphenol A, methylene blue, and amoxicillin. To mimic the breathing process in alveoli, an ultrathin air cathode was fabricated by sputtering Pt (loading as small as 0.01 mg cm−2) on nanoporous polyethylene film, contributing to fast oxygen diffusion and abundant gas-liquid-solid three-phase reactive sites. The construction of this dual-biomimetic PFC system resulted in an open circuit voltage of 0.92 V and a record-high power output of 500 μW cm−2 under simulated solar light. The series connection of modularized reactors allowed for the successive purification of wastewater by self-generated electricity. Thus, this work opens up new opportunities of biomimetic photocatalytic system for addressing the water-energy nexus.