Light-Driven Hydrogenation–Dehydrogenation of Toluene–Methylcyclohexane by Plasmonic Photocatalysis

Abstract The development of an efficient and reversible hydrogen storage and transport system is crucial for a sustainable hydrogen economy. Liquid organic hydrogen carriers (LOHCs) offer a potential solution due to their high hydrogen storage density and ease of transport, but conventional thermal approaches for the hydrogenation and dehydrogenation of LOHCs remain heavily reliant on harsh operating conditions. Here, we demonstrate a plasmonic photocatalysis approach for toluene hydrogenation to methylcyclohexane and methylcyclohexane dehydrogenation to toluene under substantially milder conditions. We observe changes in reaction orders and substantial reductions in activation barriers by 0.34 and 1.11 eV for toluene hydrogenation and methylcyclohexane dehydrogenation, respectively, as compared to thermocatalysis due to the role of hot carriers. Both reactions exhibit high activity, stability (>70 h), and excellent selectivity (>95%), offering a sustainable pathway for on-demand hydrogen storage and release.