Phase-Dependent Stability and Substrate-Induced Deactivation by Strong Metal-Support Interaction of Ru/TiO 2 Catalysts for the Hydrogenation of Levulinic Acid

Abstract

The choice of support type has a profound influence on catalyst performance in liquid phase hydrogenation reactions, including the catalytic hydrogenation of biomass-derived levulinic acid (LA) to γ-valerolactone (GVL). Catalytic performance, including stability, of three Ru/TiO 2 catalysts, having a similar mean Ru metal nanoparticle size but supported on three types of TiO 2 , namely P25, rutile and anatase, is evaluated by multiple reuse under batch reactor conditions. T3he catalysts’ physicochemical properties before and after recycling are characterized by XRD, STEM, TGA and FT-IR after CO stepwise adsorption. The results show that the deactivation seen for (mixed) anatase-supported catalysts in dioxane can be attributed to strong metal-support interaction (SMSI) rather than coke formation or metal sintering, with the rutile-based catalyst being more resistant against such support reduction. Notably, SMSI formation under the applied, relatively mild conditions only occurs in the presence of organic acids, such as LA or valeric acid.