Defects‐Induced Single‐Atom Anchoring on Metal–Organic Frameworks for High‐Efficiency Photocatalytic Nitrogen Reduction

Abstract

AbstractAiming to improve the photocatalytic activity in N2 fixation to produce ammonia, herein, we proposed a photochemical strategy to fabricate defects, and further deposition of Ru single atoms onto UiO‐66 (Zr) framework. Electron‐metal‐support interactions (EMSI) were built between Ru single atoms and the support via a covalently bonding. EMSI were capable of accelerating charge transfer between Ru SAs and UiO‐66, which was favorable for highly‐efficiently photocatalytic activity. The photocatalytic production rate of ammonia improved from 4.57 μmol g−1 h−1 to 16.28 μmol g−1 h−1 with the fabrication of defects onto UiO‐66, and further to 53.28 μmol g−1 h−1 with Ru‐single atoms loading. From the DFT results, it was found that d‐orbital electrons of Ru were donated to N2 π✶‐antibonding orbital, facilitating the activation of the N≡N triple bond. A distal reaction pathway was probably occurred for the photocatalytic N2 reduction to ammonia on Ru1/d‐UiO‐66 (single Ru sites decorated onto the nodes of defective UiO‐66), and the first step of hydrogenation of N2 was the reaction determination step. This work shed a light on improving the photocatalytic activity via feasibly anchoring single atoms on MOF, and provided more evidences to understand the reaction mechanism in photocatalytic reduction of N2.