Fe─N 5 ‐Induced Coordination Engineering of Mo Single‐Atom: Dual Sites Synergistically Enhancing Photocatalytic H 2 O 2 Generation and Activation

The photo‐Fenton technique is a promising strategy for eliminating recalcitrant organic pollutants, coupling photocatalytic two‐electron oxygen reduction (2e − ORR) for hydrogen peroxide (H 2 O 2 ) generation with subsequent activation of H 2 O 2 to hydroxyl radicals ( • OH) via the one‐electron (1e − ) Fenton process. To solve the distinct favorable active sites and mismatched selectivity between 2e‒ oxygen reduction reaction and 1e ‒ Fenton process, we propose a Fe─N 5 ‐induced coordination engineering strategy of Mo single‐atom to prepare Fe‐Mo SA /ultra‐thin carbon nitride (UCN) photocatalysts, achieving a H 2 O 2 production rate of 2585.40 μmol g –1 h –1 in pure water under ambient air and >99% degradation of Rhodamine B under natural sunlight. The excellent performance of Fe‐Mo SA /UCN for H 2 O 2 generation and activation thanks to the optimized the charge dynamics and the synergistic effect of dual sites. Theoretical calculations evidence that regulated Mo─N 3 greatly facilitate O 2 adsorption and reduce the energy barrier of 2e − ORR. The generated H 2 O 2 spontaneously migrates to the introduced Fe─N 5 sites for in situ activation to generate • OH. Furthermore, outdoor and continuous‐flow experiments also demonstrate the excellent practical applicability of Fe‐Mo SA /UCN. Overall, this study demonstrates the great potential of dual‐active‐site modulation in advancing photo‐Fenton catalysis, providing atomic‐level insights for designing high‐performance solar energy conversion systems.