Heteropoly acids regulate the hydrogenolysis of glycerol to 1,3-propanediol

The transformation of glycerol, a major and abundant byproduct from biodiesel production, can advance benefits of integrating biodiesels into current chemical productions. Meanwhile, selective production of 1,3-propanediol vs. 1,2-propanediol has emerged as a challenge for the hydrogenolysis of glycerol. Here we reported the introduction of heteropoly acids, namely silicotungstic acid, into a platinum supported titanium dioxide (Pt/TiO 2 ) catalyst, led to the formation of 1,3-propanediol at a reaction temperature of 180 °C and low hydrogen pressure of 0.5 MPa. Pyridine-IR confirmed the presence of Brønsted acids with the addition of heteropoly acids. Ammonia temperature-programmed desorption (NH 3 -TPD) revealed that heteropoly acids contribute to an increase of strong acid sites. X-ray photoelectron spectroscopy (XPS) and carbon monoxide diffuse reflectance infrared Fourier transform spectroscopy (CO-DRIFTS) suggested that the heteropoly acids facilitate coordination between the platinum species and titanium dioxide support. Probe reactions using various reactants revealed that Brønsted acid sites play a distinct role compared with Lewis acid sites in terms of directing the reaction pathways. Coupled with in-situ glycerol hydrogenolysis DRIFTS studies, a dehydration‑hydrogenation mechanism is proposed to govern glycerol hydrogenolysis to 1,3-propanediol over the heteropoly acid-modified platinum supported titanium (Pt-HPA/TiO 2 ) catalyst. • Hydrogenolysis of glycerol was performed at 180 °C and a low H2 pressure of 0.5 MPa. • Heteropoly acids modulate coordination between platinum and titanium dioxide. • Brønsted acids facilitate the formation of 1,3-propanediol.