The Reaction Mechanism and Rates at Ru Single-Atom Catalysts for Hydrogenation of Biomass BHMF to Produce BHMTHF for Renewable Polymers
Liyuan Huai, Jian Zhang, William A. Goddard III
Abstract
Realizing high selectivity for producing biodegradable 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF) for renewable polymers from 5-hydroxymethylfurfural (HMF) biomass through ring hydrogenation on single-atom catalysts poses a considerable challenge due to the complexity of HMF functional groups and the difficulty of H<sub>2</sub> dissociation. We developed a detailed reaction mechanism based on <i>ab initio</i> molecular dynamics (AIMD) and quantum mechanics (QM) to find that Ru single-atom catalysts can simultaneously dissociate H<sub>2</sub> and perform the ring hydrogenation of biomass-derived 2,5-bis(hydroxymethyl)furan (BHMF) to produce biodegradable BHMTHF, with a free energy barrier of 0.82 eV. The unique property of Ru single-atom sites enables H<sub>2</sub> to dissociate easily on a single active site of Ru to participate directly in the reaction without diffusion. Furthermore, our predicted reaction rate from microkinetic analysis indicates that ring hydrogenation and side-chain hydrogenolysis are much faster than ring-opening hydrogenation over the range of 300-550 K. The product BHMTHF dominates with a selectivity of 98.9% at 300 and 78.4% at 550 K (the second product is 5-methylfurfural (5-MFA)). This study underscores the unique effectiveness of Ru single atoms in ring hydrogenation reactions using H<sub>2</sub> as the hydrogen source, offering insights for the design of single-atom catalysts for other biomass reactions.
Group Members
Huai, L., Zhang, J., & III, W. A. G. (2024). The Reaction Mechanism and Rates at Ru Single-Atom Catalysts for Hydrogenation of Biomass BHMF to Produce BHMTHF for Renewable Polymers. *J. Am. Chem. Soc.*, *146*(45), 31251–31263. https://doi.org/10.1021/jacs.4c11551