A ligand-based solid solution approach is employed to incorporate sulphonic acid functional groups into the porous coordination polymer Cr-MIL-101. Loaded with Pd nanoparticles these Pd/MIL-101-SO3H materials act as bifunctional catalysts for the one-pot conversion of γ-valerolactone into ethyl valerate (up to 83% yield). The catalysts were extensively characterized before and after reaction. The influence of the sulfonic acid group density and the reaction conditions on the catalytic activity was systematically investigated and the reaction network for γ-valerolactone upgrading was discussed.
