Hydrodeoxygenation of lignin-derived guaiacol using ruthenium‑titanium-oxide aerogel catalysts

Catalytic hydrodeoxygenation of biomass-derived oxygenates to deoxygenated chemicals and fuels is a major research area, but selective production of aromatic compounds remains challenging, because complete deoxygenation favors formation of saturated alkanes and cycloalkanes. In this study, a highly dispersed ruthenium‑titanium oxide aerogel catalyst was synthesized via co-gelation of ruthenium and titanium precursors for the hydrodeoxygenation of lignin-derived guaiacol, which demonstrated good selectivity toward aromatic compounds, yielding 23% benzene and 47% phenol, with 48% oxygen atom removal. The catalyst's complex structure, comprising titanium oxide and ruthenium nanoclusters, was characterized using experimental methods and density functional theory calculations, which suggest that the synergy between ruthenium single atoms, nanoclusters, particles, and titanium oxide improves the selective conversion of guaiacol to benzene.