Photochemical H<sub>2</sub> dissociation for nearly quantitative CO<sub>2</sub> reduction to ethylene.

Jin, Ping; Guo, Pu; Luo, Nengchao; Zhang, Hui; Ni, Chenwei; Chen, Ruotian; Liu, Wei; Li, Rengui et al. · Science · 2025

basic_science · Level V

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Abstract

Producing olefins by carbon dioxide (CO<sub>2</sub>) hydrogenation is a long-standing goal. The usual products are multicarbon mixtures because the critical step of heterolytic hydrogen (H<sub>2</sub>) dissociation at high temperatures complicates selectivity control. In this study, we report that irradiating gold-titanium dioxide at 365 nanometers induces heterolytic H<sub>2</sub> dissociation at ambient temperature. This process likely relies on interfacial electric dipoles from photogenerated electrons and holes situated on the metallic gold nanoparticles and interfacial gold-oxygen-titanium scaffolds. The heterolytic H<sub>2</sub> dissociation is further promoted by light-induced coating of gold nanoparticles with a titanium oxide layer. The resulting nucleophilic hydrogen species reduce CO<sub>2</sub> to ethane in >99% yield under light irradiation in a flow apparatus. Furthermore, cascading with a subsequent photocatalytic ethane dehydrogenation generates ethylene in >99% yield over 1500 hours of irradiation.