Unassisted Switchable Dual‐Photoelectrode Devices Utilizing p‐n Carbon Quantum Dots as “Semiconductor Electrolytes”: Optimization Between H2O2 and Solar Electricity Production

Abstract Switchable self‐driven photoelectrochemical (PEC) devices are developed to boost H2O2 or electricity generation under visible‐light illumination, in which p‐n type carbon quantum dots (N‐CQDs) is applied as conceptually‐new “semiconductor electrolytes”. The N‐CQDs contains N‐dopants, and bo...

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Main Authors: Hui‐Min Duan, Chen‐Guang Li, Liu‐Meng Mo, Jing‐Shuang Dang, Xiao‐Hui Jia, Jia‐Cheng Yu, Yu‐Hang Mei, Anders Thapper, Hong‐Yan Wang
Format: Article
Language:English
Published: Wiley 2025-08-01
Series:Advanced Science
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Online Access:https://doi.org/10.1002/advs.202417204
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Summary:Abstract Switchable self‐driven photoelectrochemical (PEC) devices are developed to boost H2O2 or electricity generation under visible‐light illumination, in which p‐n type carbon quantum dots (N‐CQDs) is applied as conceptually‐new “semiconductor electrolytes”. The N‐CQDs contains N‐dopants, and both negatively‐ and positively‐charged surface groups. This allows N‐CQDs to act as the electrolyte and to interact with both a BiVO4 photoanode and a Cu2O photocathode. In a two‐compartment cell with a separating membrane, N‐CQDs can dynamically form p‐n heterojunctions with the photoanode or the photocathode, facilitating charge separation. In this setup, the fine‐tuned electronic structure of N‐CQDs promotes the two‐electron reactions with water or O2 to produce H2O2, achieving a rate of 28 µm min−1 and Faradic efficiency exceeding 80%. Switching into a one‐compartment cell, N‐CQDs promotes four‐electron charge transfer and stabilizes the photoelectrodes, giving electricity output for over 120 h. This control over electron transfer, selectivity, and durability cannot be achieved using traditional electrolytes.
ISSN:2198-3844