Visible-light-driven non-oxidative dehydrogenation of alkanes at ambient conditions

Direct non-oxidative dehydrogenation of alkanes produces useful carbon feedstocks and hydrogen fuel. However, breaking the C–H bonds in alkanes typically requires high temperature, stoichiometric oxidants or high-energy ultraviolet light; processes that operate under milder conditions are attractive but tend to have poor efficiency. Here we report Pt/black TiO2 photocatalysts in which Pt species are close to each other but not directly bonded, exhibiting high performance for alkane dehydrogenation in visible to near-infrared light at room temperature. For cyclohexane dehydrogenation, the turnover number for H2 production exceeded 100,000 without any deactivation over 80 reaction cycles, far beyond thermal reactions. For methane, 8.2% conversion was achieved with 65% selectivity to propane, rather than the more common ethane. We propose that methane undergoes intramolecular dehydrogenation to produce a methylene intermediate. For C2+ alkanes, fast dehydrogenation (up to 1,440 µmol g−1 h−1) to the corresponding olefins was realized. Distinct from isolated Pt+ monomers, the collections of Pt+ monomers give better photocatalytic activity and selectivity.