Crystal Phase Sensitivity of 5‑Hydroxymethylfurfural Hydrodeoxygenation over a Pt₁Co Single-Atom Alloy Catalyst

In reactions of hydrodeoxygenation (HDO) of biomass-derived chemicals, one promising method for improving the yield of desirable products is to control the crystal phase of the catalyst and thus the adsorption configuration of intermediates. In this work, we have investigated the catalytic activity and selectivity of Pt1Co single-atom alloy (SAA) catalysts with fcc (face-centered cubic) and hcp (hexagonal close-packed) cobalt crystal phases toward 5-hydroxymethylfurfural (5-HMF) HDO reaction by density functional theory (DFT) calculation. Potential energy profiles of 5-HMF HDO reactions on the Pt1Co-fcc and Pt1Co-hcp surfaces show that the Pt1Co-hcp surface has a lower hydrogenation energy barrier (0.96 and 0.83 eV) and C–O bond cleavage energy barrier (0.58 and 0.44 eV) than the Pt1Co-fcc surface, indicating the Pt1Co-hcp surface exhibits higher catalytic activity. Ring-opening energy and ring hydrogenation calculations distinguish product selectivity: the optimal product on the Pt1Co-hcp surface is 2,5-dimethyltetrahydrofuran (DHMF), but 2-hexanol on the Pt1Co-fcc surface, which is caused by atomic density difference from the crystalline phase. This work provides a new theoretical support to improve reaction activity and product selectivity by controlling the crystal phase of biomass HDO catalysts