Synergistic Bimetallic Pd–Pt/TiO₂ Catalysts for Hydrogenolysis of Xylitol with In Situ-Formed H₂

Hydrogenolysis of xylitol can produce value-added glycols and alcohols for industrial chemicals. However, it is often carried out under elevated temperature and pressure, causing unfavorable catalyst deactivation and significant formation of side products. Catalytic transfer hydrogenolysis of xylitol, under much milder conditions, is largely unexplored in this field. Herein, we reported transfer hydrogenolysis of xylitol with in situ -formed H 2 in batch slurry reactors over synergistic Pd–Pt/TiO 2 catalysts. Although monometallic Pd/TiO 2 and Pt/TiO 2 catalysts display poor activity and selectivity, bimetallic Pd–Pt/TiO 2 catalysts showed synergetic performances for tandem H 2 generation and hydrogenolysis of xylitol. A combined yield of 41.1% to propylene glycol and ethylene glycol was thus obtained on the Pd–Pt/TiO 2 catalyst at 220 °C and 1 MPa N 2 . Detailed structure-dependency studies on PdPt particle size (2.4–5.2 nm) revealed that C–H, C–O, and C–C bond cleavage displays strong size-determining trends. Therefore, conversion of xylitol displays an optimal selectivity toward glycols and alcohols with a PdPt particle size of approximately 4.4 nm. In addition, influence of experimental parameters, including temperature (200–230 °C), N 2 pressure (0–3 MPa), and alkali/xylitol molar ratio (0–0.25), was also studied with respect to conversion and production distribution. The outcome of this work offers mechanistic insights into atom-efficient conversion of bioderived oxygenates to renewable chemicals.