A comparison of Structure–Activity of Cu-Modified Over Different Mesoporous Silica Supports for Catalytic Conversion of Levulinic Acid

Abstract

Catalytic hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) was investigated over four different types of mesoporous silica (SBA-15, MCM-48, MCM-41, and KIT-6) supported copper (5 wt.%) catalysts. The Cu was incorporated into mesoporous silica supports by a sequential impregnation method. A detailed investigation of the support structure–activity correlation and the performance of the catalysts in LA conversion was studied. Detailed characterisation techniques were used to evaluate the physical and catalytic properties of the studied catalysts. The structure type and physicochemical properties of the silica support had a significant effect on the overall performance of the catalysts. Among them, over Cu/SBA-15 catalyst, a complete levulinic acid (LA) conversion with ~ 98% gamma valerolactone (GVL) selectivity was achieved at 265 °C under ambient H2 pressure. The superior performance of Cu/SBA-15 catalyst was attributed to the high surface acidity, reducibility of Cu oxides species, and highly dispersed Cu particles over SBA-15 structure. The results confirmed that the activity of the catalysts is significantly influenced by the textural properties, surface acidity and copper dispersion. Durability of all the catalysts were also tested for 50 h time on stream and over SBA-15 catalyst, only a small drop in the activity was observed.