Solar‐Driven Reversible Hydrogen Storage of Sodium Cyclohexanolate/Phenoxide Pair

Abstract Reversible hydrogen storage is a key challenge for the implementation of hydrogen energy, with dehydrogenation being particularly difficult because of its endothermic nature, slow kinetics, poor selectivity, etc. Solar energy‐driven hydrogen uptake/release represents an interdisciplinary approach that provides an effective solution to those problems. Herein, we report the solar‐driven reversible hydrogen uptake of 4.9 wt.% over sodium cyclohexanolate/phenoxide pair, achieving over 99.9% conversion and selectivity in both hydrogenation and dehydrogenation via photocatalysis without external heating. Notably, the initial dehydrogenation rate reaches 23.4mmo l H 2g cat − 1h − 1${\mathrm{mmo}}{{{\mathrm{l}}}_{{{{\mathrm{H}}}_2}}}{{{\mathrm{g}}}_{{\mathrm{cat}}}}^{ - 1}{{{\mathrm{h}}}^{ - 1}}$ that is ca. 2 orders of magnitude higher than thermocatalysis. The superior photocatalytic performance stems from the synergy between high‐ and low‐frequency light, i.e., low‐frequency light mainly provides heat, high‐frequency light drives the desorption of product from the catalyst surface. This approach offers a path toward a sustainable solar‐driven hydrogen energy system.