Single‐atom Electronic Bridge Facilitates Cascade Electron Transfer From Encapsulated Polyoxometalate to Metal‐Organic Framework for Efficient Photocatalytic CO ₂ Conversion

Abstract

Abstract The POM@MOF system, integrating the exceptional properties of polyoxometalates (POM) and metal‐organic frameworks (MOF), exhibits considerable catalytic potential. However, the absence of stable and well‐defined electron‐transfer pathways between the two components hampers charge separation and transport, thereby limiting its catalytic efficiency. Here, we constructed a Ni single‐atom electronic bridge (SAEB) between POM and MOF, based on our previously‐reported PMo 11 W@ rht ‐MOF‐1 composite. Spherical aberration‐corrected transmission electron microscopy and X‐ray absorption spectroscopy analyses revealed not only the hierarchical dispersion of single‐atom Ni, POM, and MOF, but also the formation of chemical bonds between Ni and both POM and MOF. This precisely engineered Ni‐SAEB facilitated cascade electron transfer from the encapsulated PMo 11 W to rht ‐MOF‐1 framework, as confirmed by femtosecond transient absorption spectroscopy and in situ X‐ray photoelectron spectroscopy. Further investigations demonstrated that the Ni‐SAEB/POM@MOF system simultaneously harnessed the “electronic sponge” effect of POM and the CO 2 adsorption‐conversion capability of MOF. Consequently, the Ni‐SAEB/PMo 11 W@ rht ‐MOF‐1 composite achieved a CO 2 ‐to‐CO photocatalytic conversion rate of 3 mmol g −1 h −1 , markedly surpassing that of PMo 11 W@ rht ‐MOF‐1 without Ni‐SAEB. This work establishes the SAEB strategy as a versatile catalytic concept, where single atoms serve as both surface catalytic centers and interfacial cascade electron mediators, with broad scientific significance.