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.