The Role of Gold Nanoparticles on Different Supports for the In-Air Conversion of Levulinic Acid into γ-Valerolactone with Formic Acid as an Alternative Hydrogen Source

Abstract

In this report, catalysts of Au nanoparticles on different supports (Au/ZrO₂, Au/C, Au/Al₂O₃, Au/SiO₂, Au/TiO₂, Au/MgO) were fabricated by co-precipitation and impregnation methods to determine the role of Au over oxides. The crystal structure and phase composition of catalyst samples before and after test reactions were investigated by X-ray diffraction technique, X-ray photoelectron spectroscopy and transmission electron microscopy. The catalytic activity was tested on the hydrogenation reaction of levulinic acid (LA) into γ-valerolactone (GVL) using formic acid (FA) as a hydrogen source. In all tested samples, Au/ZrO₂-D (was fabricated by co-precipitation method) gave the best GVL yield of 85.0% with very low amount of catalyst loading (catalyst/reactant 1 wt). The existent of Au³⁺ in the catalyst system may be the main factor to improve the yield of GVL formation.