Thermokinetic stabilization of sub-nanometer Cu+ clusters via molten-salt flux for highly selective photocatalytic alcohol partial reforming

Traditional photocatalytic alcohol reforming often suffers from uncontrolled deep oxidation, leading to undesirable greenhouse gas (CO 2 ) emissions and the loss of valuable carbon resources. To address this environmental and engineering bottleneck, a highly dispersed, sub-nanometer Cu + cluster/TiO 2 catalyst with engineered oxygen vacancies was constructed via a scalable, one-step molten-salt strategy. The highly polarized liquid flux provides a localized salt-thermal microenvironment that thermodynamically stabilizes the highly active Cu + state and effectively prevents cluster agglomeration under ambient air calcination. The optimized catalyst delivers a promising photocatalytic hydrogen evolution rate of 181.89 mmol g-1 over 4 h, achieving an apparent quantum yield (AQY) of 27.1% at 365 nm. Notably, this non-noble-metal system outperforms highly active noble-metal benchmarks under identical conditions. Crucially, detailed characterizations indicate that the highly dispersed Cu + clusters significantly modulate surface adsorption configurations rather than relying on macroscopic plasmonic effects. This robust sub-nanoscale interfacial coupling selectively drives targeted dehydrogenation and dehydration pathways. Consequently, the catalyst suppresses parasitic C-C bond cleavage, keeping CO and CO 2 emissions below the detection limit of GC-TCD while maximizing active hydrogen extraction and co-producing value-added chemicals (e.g., highly selective production of formaldehyde from methanol, alongside valuable C 2 products from ethanol). This work presents a sustainable, easily scalable engineering paradigm for waste alcohol valorization, effectively bridging green hydrogen production with carbon-neutral chemical synthesis.