Isolated Single-Atomic Ru Catalyst Bound on a Layered Double Hydroxide for Hydrogenation of CO2 to Formic Acid

In order to achieve an economical CO2-mediated hydrogen energy cycle, the development of heterogeneous catalysts for CO2 hydrogenation to formic acid is an urgent and challenging task. In this study, a stable and well-defined single-site Ru catalyst on the surface of a layered double hydroxide (LDH) in a basic medium is proven to be efficient for selective hydrogenation of CO2 to formic acid under mild reaction conditions (2.0 MPa, 100 °C). The electron-donating ability of triads of basic hydroxyl ligands with a particular location is crucial for an active electron-rich Ru center. There is a strong correlation between catalytic activity and adjustable CO2 adsorption capacity in the vicinity of the Ru center. Such electronic metal–support interactions and a CO2 concentration effect result in a significant positive influence on the catalytic activity.