Highly Strained Bi‐MOF on Bismuth Oxyhalide Support with Tailored Intermediate Adsorption/Desorption Capability for Robust CO2 Photoreduction

Abstract Herein, using as‐designed surface‐mounted Bismuth‐based metal‐organic framework (Bi‐MOF) on two‐dimensional BiOBr support, as an operable platform for site‐specific strain engineering to tailor the intermediate adsorption/desorption capability in CO2 photocatalytic conversion is proposed. Giant compressive strain up to 7.85 % is successfully induced on the surface‐mounted Bi‐MOF revealed by HRTEM images and geometric phase analysis as well as in situ Raman characterization, which largely downshifts the p band center of Bi nodes and intensifies their unsaturated state. In‐depth explorations are put onto p‐p (Bi 6p and CO2/CO 2p) orbital hybridization. Taking the adsorption process as an example, the 1π and 7σ frontier molecule orbitals of CO2 2p for both the strain‐free and strained models shift downwards the Fermi level, indicative of fast adsorption of CO2. Meanwhile, strain engineering further induces new non‐degenerate orbital overlapping near 1π and intensified overlapping of 7σ orbitals, stimulating the fast activation of absorbed CO2 molecules.