The effect of flow conditions on the activity and stability of Pt/LaAlO3 perovskite catalyst during aqueous phase reforming of glycerol

We present a systematic investigation of key reaction parameters (WHSV, hydrogen/gas-liquid ratio, time, pressure) on the activity and stability of Pt/LaAlO3 perovskite catalysts during the aqueous phase reforming of glycerol at 240 C and 40 bar. Reactor configuration (batch vs continuous) strongly influences product selectivity. While batch conditions promote lactic acid production which contributes to the complete decomposition of LaAlO3 phase and activity loss within 6 h, flow conditions facilitate the hydrogenation of hydroxyacetone and 1,2-propanediol intermediates to improve progression along the desired reforming pathway. After an initial induction period, associated with partial perovskite transformation into LaCO3OH and doubling of Pt nanoparticle size, catalysts remained stable over an extended 30 h experiment. Catalyst activity increased with increasing gas-liquid phase ratio (co-feeding of argon) and particularly after decreasing the reaction pressure into the 2-phase region (20 bar), resulting in 5-fold increase in conversion and complete retention of the LaAlO3 phase.