Site-Selective Pt Anchoring on Oxygen Vacancies by Atomic Layer Deposition Promotes Metal–Acid Synergy for Enhanced Guaiacol Hydrodeoxygenation

For metal-acid bifunctional catalysts, accurately tuning the spatial distribution of catalytic sites and enhancing the metal-acid synergy remain a challenge. To this end, we combine oxygen vacancy (O_v) engineering with atomic layer deposition (ALD) on Nb₂O₅·nH₂O to simultaneously achieve highly dispersed Pt, enhanced Brønsted acid site (BAS) concentration, and optimized metal-acid synergy. Specifically, for the Pt/O_v-Nb₂O₅·nH₂O catalyst, the abundant O_vs formed in the O_v-Nb₂O₅·nH₂O via H₂ heat treatment guide more ALD Pt selective anchoring, thus forming smaller Pt clusters. Additionally, Pt species on the O_vs intensify local NbO₆ distortion, inducing more BASs. These acid sites are in close proximity to Pt species, enhancing metal-acid synergistic catalysis. By contrast, Pt/Nb₂O₅·nH₂O, prepared by directly depositing Pt on Nb₂O₅·nH₂O, exhibits a larger Pt cluster size and lower BAS concentration. Consequently, Pt/O_v-Nb₂O₅·nH₂O exhibits efficient guaiacol conversion and higher cyclohexane selectivity than Pt/Nb₂O₅·nH₂O in guaiacol hydrodeoxygenation (HDO). This endeavor offers guidelines for the rational design of metal-acid bifunctional catalysts.