Synergy of Palladium Nanoparticles and Single Atoms Promoted Tandem Reactions to Produce Hydroxyl Radical for Efficient Photoelectrochemical Water Purification

ABSTRACT Enhancing the highly selective photocatalytic generation of hydroxyl radical for water purification is extremely desirable but remains challenging since it normally requires a series of reactions associated with different catalysts. Here we report a synergistic catalyst (Pd SAs+NPs /V vac ‐BiVO 4 ) with dual‐functional active sites of palladium nanoparticles and single‐atoms that are coordinatively responsible for the synthesis and decomposition of H 2 O 2 in an optimized tandem reaction pathway. The application of this catalyst in the photoelectrochemical system can significantly enhance the production of H 2 O 2 and •OH, with yields that are 531 and 3.5 times higher than its counterparts, respectively. Importantly, this catalyst can be applied for efficient water purification with superior performances including high catalytic activity and stability, wide applicability for different refractory pollutants, excellent performance in real‐water systems, and good detoxification property. Physical, theoretical and in situ spectroscopy investigations show the crucial role of Pd SAs+NPs /V vac ‐BiVO 4 catalyst, where the Pd nanoparticles promote the generation of H 2 O 2 via O 2 activation and further its desorption and migration to the nearby Pd single‐atom sites via spillover, while the Pd single‐atoms boost the catalytic decomposition of H 2 O 2 to •OH. This study provides new insights into •OH production via the design of synergistic catalyst with dual‐functional active sites for enhanced water purification.