Constructing the separation pathway for photo-generated carriers by diatomic sites decorated on MIL-53-NH₂(Al) for enhanced photocatalytic performance

High yield production of phenol from hydroxylation of benzene with low energy consumption is of paramount importance, but still challenging. Herein, a new strategy, consisting of using diatomic synergistic modulation (DSM) to effectively control the separation of photo-generated carriers for an enhanced production of phenol is reported. The atomic level dispersion of Fe and Cr respectively decorated on Al based MIL-53-NH₂ photocatalyst (Fe₁/Cr:MIL-53-NH₂) is designed, in which Cr single atoms are substituted for Al³⁺ while Fe single atoms are coordinated by N. Notably, the Fe₁/Cr:MIL-53-NH₂ significantly boosts the photo-oxidation of benzene to phenol under visible light irradiation, which is much higher than those of MIL-53-NH₂, Cr:MIL-53-NH₂, Fe₁/MIL-53-NH₂, and Fe nanoparticles/Cr:MIL-53-NH₂ catalysts. Theoretical and experimental results reveal that the Cr single atoms and Fe single atoms can act as electron acceptor and electron donor, respectively, during photocatalytic reaction, exhibiting a synergistic effect on the separation of the photo-generated carriers and thereby causing great enhancement on the benzene oxidation. This strategy provides new insights for rational design of advanced photocatalysts at the atomic level.