Alumina supported bimetallic Pt–Fe catalysts applied to glycerol hydrogenolysis and aqueous phase reforming

Abstract

Glycerol hydrogenolysis and aqueous phase reforming (APR) are processes that can transform glycerin into 1,2-propanediol (1,2-PD), ethylene glycol (EG), alcohols, ketones and hydrocarbons. This study was performed using five Ptx–Fey/Al2O3 catalysts in both glycerol hydrogenolysis and APR reactions, with 2.5%wt. metallic Pt total loading and varying Pt:Fe atomic ratios (1:0; 0:1; 2:1; 1:1; 1:2). The catalysts were analyzed by XRD, TPR, XPS, FT-IR, TEM, N2 physisorption and H2 chemisorption, and catalytic tests were undertaken in batch reactions. Except for Fe/Al2O3, all catalysts were active for both APR and hydrogenolysis reactions, in which bimetallic Ptx–Fey/Al2O3 showed better selectivity towards 1,2-PD than Pt/Al2O3. From characterization, it is clear that Pt–Fe interaction displays a pivotal role in enhancing catalytic activity, through the generation of new sites. From the catalytic tests, rate constants and TOF’s were calculated. The addition of Fe had a positive effect both in activity and in selectivity for hydrogenolysis towards 1,2-PD. In APR, there is considerable H2 production, and although activity is greater, there is a slight decline in 1,2-PD production. Through comparison of both reactions’ products, it is evident that some of the hydrogen used in glycerol hydrogenolysis comes from glycerol reforming. Glycerol APR over Ptx–Fey/Al2O3 catalysts seems to be a viable alternative for low temperature H2 production.