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Efficient Light-Driven Fuel Cell with Simultaneous Degradation of Pollutants on a TiO2 Photoanode and Production of H2O2 on a Gas Diffusion Electrode Cathode

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journal contribution
posted on 04.05.2021, 20:33 by Tian Wang, Fei Ye, Shuai Wu, Shuo Chen, Hongtao Yu, Xie Quan
Photoelectrochemical (PEC) reduction of O2 to H2O2 via a two-electron reaction pathway is an attractive strategy for decentralized and sustainable H2O2 generation. However, the low selectivity, inadequate mass transfer efficiency of cathodic O2 reduction, as well as the high overpotential of the anodic half-reaction of H2O oxidation together limit the efficiency of the PEC system. Here, an elaborately designed PEC system coupling O2 reduction on a gas diffusion electrode (GDE) with organic pollutants oxidation on a TiO2 nanotube arrays (TNTs) photoanode is assembled for simultaneously tackling the aforementioned limitations. Benefiting from the synergistic effect between accelerated O2 mass transfer and alleviated anodic overpotential, this PEC system exhibits a H2O2 generation rate of 34.7 μmol L–1 h–1 cm–2 at the cathode, which is 3.49 times higher than that of the system with neither the GDE nor pollutants (9.93 μmol L–1 h–1 cm–2). Moreover, over 88% of pollutants, such as phenol and benzoic acid, can be degraded, and the mineralization rate can surpass 70% at the anode. This work proposes a new insight into developing a dual-functional PEC system for H2O2 production and simultaneous pollutants degradation.