Cooperative Brønsted Acid-Single Atom Photocatalysis in Metal-Organic Framework

Enzymes, composed of earth-abundant elements, outperform conventional heterogeneous photocatalysts in hydrogen production due to the dual-site cooperation between adjacent active metal sites and proton-transferring ligands. However, the realization of such dual-site cooperation in heterogeneous catalytic systems is hindered by the challenges in the precise construction of cooperative active sites. In this study, we present the design of a structurally tuned metal-organic framework (MOF) photocatalyst that incorporates cooperative Brønsted acid-single atom catalytic sites. By grafting Co single-atom sites onto the Ti-oxo clusters and introducing Brønsted acidic P-OH moieties in tandem within the MOF-based catalyst structure, we achieved a visible-light-activated photocatalytic H₂ production rate of 6.6 mmol g^-1 h^-1, which is 6.6 times higher than that of a Pt nanoparticle-based cocatalyst, emphasizing the significance of incorporating cooperative Brønsted acid-single atom catalytic sites.