Engineered atomic Pd sites on a supermolecule nanosheet for efficient hydrogen peroxide photosynthesis

Solar-driven hydrogen peroxide (H 2 O 2 ) synthesis from water and oxygen stands as a sustainable and viable strategy, yet its progress remains constrained by the lack of high-performance photocatalysts. Here we report a Pd atomic site on tetrakis (4-carboxyphenyl) porphyrin supramolecular nanosheet catalyst for photocatalytic H 2 O 2 production. The optimized catalyst achieves an exceptional H 2 O 2 yield rate of 608 μmol g −1  h −1 under visible light. A combination of experimental investigations and theoretical simulations verifies that the H 2 O 2 generation proceeds via a dual-pathway mechanism, encompassing both the oxygen reduction reaction (ORR) and the water oxidation reaction (WOR). The Pd atomic sites not only enhance visible-light absorption and facilitate charge transport, but also serve as efficient electron traps that significantly lower the energy barriers for the formation of key intermediates (*OOH for the ORR pathway and *OH for the WOR pathway). This work presents a high-performance photocatalytic system and delivers atomic-scale insights into the sustainable solar-driven H 2 O 2 synthesis process.