Strong metal support interaction in Ru/V2O3 catalyst reduces reactant induced poisoning during succinic acid hydrogenation

Abstract

Hydrogenation of carboxylic acids to lactones and alcohols is an important reaction. However, strong adsorption of carboxylic acid on the catalyst surface leads to poisoning of the active site, demands harsher reaction condition and use of organic solvents. In this study, we demonstrate that the strong metal support interaction (SMSI) and hydrogen spillover on Ru/V2O3 can counter the poisoning effect. The Ru/V2O3 catalysts reduced at 400 C formed a layer of V2O3 over Ru. The catalyst was able to hydrogenate succinic acid to gamma-butyrolactone (GBL) in 77 % yield in the presence of water at mild conditions of 150 C and 6 h. H2-D2 exchange experiment showed that for the Ru/V2O3 without SMSI the H2 dissociation was inhibited due to the adsorption of substrate over Ru surface, whereas catalysts with SMSI effect created a barrier between the substrate and the hydrogen dissociation sites. Spillover of dissociated H2 onto the V2O3 surface was found to enhance the catalytic activity. Thermodynamics calculations using density functional theory showed that transfer of a hydride from Ru and proton from V2O3 to the substrate have a lower reaction free energy compared to that of transfer of two hydrogen atoms from a bare ruthenium surface. Additionally, weaker adsorption of substrates and easier desorption of product from the Ru/V2O3 surface increased catalytic activity compared to that of bare ruthenium surface. We show that the general concept of using SMSI to mitigate poisoning can be applied to catalytic hydrogenation of substrates that adsorb on metal sites.