Probing supported bimetallic Pt–In sites in glycerol hydrogenolysis

Abstract

This work studied platinum and indium supported on alumina and silica as monometallic and bimetallic catalysts for the aqueous phase hydrogenolysis of glycerol towards 1,2-propanediol (1,2-PDO). The prepared catalysts were characterized by N₂ physisorption, XRD, TPR, pyridine adsorption DRIFTS, TPD-H₂, TPD-CO, H₂ and CO chemisorption, and TEM. For alumina-supported catalysts, there was a conversion of 39% when using Pt/Al₂O₃ and 33% when using Pt–In/Al₂O₃. The In/Al₂O₃ catalyst did not perform well, showing a conversion of 2%. Turnover frequencies for Pt/Al₂O₃ and Pt–In/Al₂O₃ showed values of 1.8 × 10⁻¹ s⁻¹ and 3.0 × 10⁻¹ s⁻¹, respectively, considering H₂ chemisorption for active site measurements. From the characterization of the catalysts, it can be inferred that In dilutes Pt in bimetallic particles, creating more selective Pt–In sites for the APH of glycerol. The influence of the catalyst structure, bimetallic Pt–In particles and different supports is discussed.