Simultaneous pollutant degradation and electricity generation by photocatalytic fuel cell with visible light responsive N-CQDs/Bi2MoO6/CuMn2O4/Ti photoanode

In this work, an efficient nitrogen-doped carbon dots (N-CQDs) doped Bi 2 MoO 6 /CuMn 2 O 4 heterojunction photoanode (N-CQDs/Bi 2 MoO 6 /CuMn 2 O 4 ) was successfully prepared via a facile hydrothermal-coupling strategy, and it was integrated with a Cu cathode to build a PFC for concurrent electricity generation and organic pollutant degradation. Approximately 92% of RhB was eliminated, accompanied by photocurrent and power output values of 8.3 mA·cm −2 and 51.0 μW·cm −2 , respectively. In addition, the open-circuit voltage and photoconversion efficiency were measured as 0.60 V and 0.12%. The superior performance of PFC originates from the integrated action of carrier separation of Bi 2 MoO 6 /CuMn 2 O 4 Z-scheme heterojunction and electron-storage function of N-CQDs, which reinforces visible-light harvesting, suppressed charge recombination, accelerates the interfacial electron transfer and sustains strong redox potentials. The degradation process involved the participation of both radical species (•OH, •O 2 ⁻ ) and non-radical species (h + ). Due to the formation of local Schottky-like contact between Bi 2 MoO 6 /CuMn 2 O 4 and N-CQDs, N-CQDs act as an efficient electron mediator, which facilitates the generation of reactive oxygen species and further enhances the degradation efficiency. This work provides a new insight into constructing quantum-dot-mediated heterojunction photoanode.