The production of H2O2 via artificial photosynthesis is often limited by inefficient charge-carrier separation, causing significant charge recombination and slow electron transfer. Herein, we report a facile strategy to regulate the photogenerated charge carrier transportation in hydrogen-bonded organic frameworks (HOFs) via the construction of charge-assisted hydrogen bonds. Specifically, the amount of charge transfer channels in the pyrene-based HOFs can be modulated from one in FDU-HOF-3 to two in WYU-HOF-1 (WYU = Wuyi University) and three in WYU-HOF-2, as evidenced by the in situ characterization and theoretical calculations, leading to the highest separation/transfer efficiency in WYU-HOF-2. In addition, the fluorine-functionalized WYU-HOF-2 also contributes to the enhanced charge migration and separation. Catalytic studies reveal that WYU-HOF-2 shows the highest H2O2 generation rate from water, oxygen, and light without sacrificial agents, which is 3.4- and 62-fold higher than that of WYU-HOF-1 and FDU-HOF-3, respectively. Mechanistic studies disclose that both of WYU-HOF-1 and WYU-HOF-2 facilitate photocatalytic H2O2 production via the 2e- oxygen reduction reaction (ORR) and the 2e- water oxidation reaction (WOR) pathways. This work offers a promising strategy for regulating charge carrier transport in HOFs, thereby enhancing their photocatalytic performance.
Zhao et al. (Tue,) studied this question.