Decoration of Ir Surface with Re Single-Atom to Match the Adsorption Configuration of Glycerol toward Selective Hydrogenolysis

Selective hydrogenolysis of glycerol to 1,3-propanediol (1,3-PDO), a valuable chemical for bioplastic production, is kinetically and thermodynamically unfavorable and thus remains challenging. To address this issue, we propose a single-atom alloy (SAA) catalyst, where oxophilic Re single-atoms and hydrophilic Ir sites synergistically tune the glycerol adsorption configuration and enhance the 1,3-PDO formation. Theoretical calculations reveal that the Re single-atom strongly binds the central C–OH group of glycerol, facilitating selective activation, while adjacent Ir sites enable hydrogen dissociation and weakly interact with terminal C–OH groups. By further combination with microkinetic modeling simulations, such an adsorption configuration is elucidated to enhance the formation of 1,3-PDO against that of 1,2-PDO via the selective hydrogenolysis of the central C–OH group of glycerol. Guided by theoretical insights, we synthesize an ordered mesoporous silica supported IrRe-SAA catalyst with single-atom Re on the Ir surface identified by detailed characterizations. Catalytic tests demonstrate a significant improvement in 1,3-PDO selectivity, as predicted by theoretical calculations, achieving a 1,3-PDO-to-1,2-PDO selectivity ratio of 9.4 at 74.8% glycerol conversion. This work highlights the potential of SAA catalysts to unlock precise control over adsorption configurations for controlling reaction pathways to form desirable products, advancing the design of high-performance catalysts for selective biomass valorization.