Steering C–H Activation by Spin-Polarized Single-Sites for Near-Unity Selective and Efficient Photocatalytic Methanol Coupling to Ethylene Glycol

Photocatalytic methanol coupling holds great promise for the sustainable production of value-added ethylene glycol (EG) and hydrogen yet remains challenging due to the difficulty in achieving selective C-H activation associated with spin-state transitions. Here, we develop a spin-polarized photocatalyst (<i>sp</i>-Mo₁/ZCS) by anchoring asymmetric spin-state Mo single-sites onto ZnCdS, enabling selective C-H activation through quantum spin exchange interactions. Consequently, it demonstrates exceptional EG selectivity (97.6%), yield (236.2 mmol g^-1), turnover number (1417.2 mol_EG mol_Mo^-1), and catalytic durability (over 100 h) in photocatalytic methanol coupling, with the EG production rate outperforming standalone ZnCdS by over an order of magnitude. We reveal that the spin-polarized Mo single-sites enhance surface polarization, thereby accelerating charge-carrier separation and migration. More importantly, they facilitate the spin-state transition of C-H activation to generate ^•CH₂OH and the subsequent C-C coupling, consequently improving the selectivity and efficiency of EG synthesis. This study highlights the pivotal role of spin-implantation in steering C-H activation for efficient photocatalytic methanol coupling and related reactions.