Upgrading light alkanes to value-added olefins is a long-standing challenge, owing to the high stability of C-H bonds and the tendency for overoxidation at elevated temperatures. Here, we introduce a light-driven strategy for ethane dehydrogenation using Cu-doped TiO2, in which atomically dispersed Cu coordinated to bridging oxygen (Obr-Cu) creates well-defined Cu-O ensembles that orchestrate site-specific, stepwise C-H activation. Photogenerated holes localize at Obr-Cu sites to initiate the first C-H cleavage, while adjacent Cu centers mediate β-H elimination and H2 evolution. In contrast, minor β-H activation at Obr-Ti sites generates *H species that cannot desorb due to a prohibitive coupling barrier with *H on Obr-Cu, leading to Cu reduction and progressive deactivation. Co-feeding CO2 restores the active Cu coordination environment and suppresses this deactivation process without perturbing the primary reaction pathway. This cooperative design achieves a C2H4 production rate of 21.1 mmol g-1 h-1 with nearly stoichiometric H2 evolution and an apparent quantum efficiency of 6.1% under 365 nm irradiation. These findings establish a site-defined, hydrogen-conserving route for photocatalytic alkane upgrading, offering a general blueprint for selective C-H bond transformations with long-term stability.
Zhang et al. (2026) studied this question.