Zeolite‐Encaged Pd–Mn Nanocatalysts for CO 2 Hydrogenation and Formic Acid Dehydrogenation

A CO 2 ‐mediated hydrogen storage energy cycle is a promising way to implement a hydrogen economy, but the exploration of efficient catalysts to achieve this process remains challenging. Herein, sub‐nanometer Pd–Mn clusters were encaged within silicalite‐1 (S‐1) zeolites by a ligand‐protected method under direct hydrothermal conditions. The obtained zeolite‐encaged metallic nanocatalysts exhibited extraordinary catalytic activity and durability in both CO 2 hydrogenation into formate and formic acid (FA) dehydrogenation back to CO 2 and hydrogen. Thanks to the formation of ultrasmall metal clusters and the synergic effect of bimetallic components, the PdMn 0.6 @S‐1 catalyst afforded a formate generation rate of 2151 mol formate mol Pd −1 h −1 at 353 K, and an initial turnover frequency of 6860 mol mol Pd −1 h −1 for CO‐free FA decomposition at 333 K without any additive. Both values represent the top levels among state‐of‐the‐art heterogeneous catalysts under similar conditions. This work demonstrates that zeolite‐encaged metallic catalysts hold great promise to realize CO 2 ‐mediated hydrogen energy cycles in the future that feature fast charge and release kinetics.