Realizing Influence of Supports in Aqueous‐Phase Hydrogenation of Furfural over Nickel Catalysts

Abstract The catalytic activity of nickel nanoparticles (5% Ni w/w loading) dispersed on different metal oxide supports has been explored for the hydrogenation of furfural. Nickel, supported on reducible oxides (CeO₂ and TiO₂), displays higher (almost 100%) conversion compared to that on non‐reducible oxide supports (SiO₂, Al₂O₃, Mg₃AlO_x). H₂‐TPR and XPS analyses bring out the influence of metal‐support interaction during the reduction of nickel precursor and their electronic properties. The adsorption and activation of furfural on the catalyst has been studied using infrared spectra and DFT calculations. The reaction proceeds via both ring‐rearrangement and ring hydrogenation pathways, with furfuryl alcohol as the primary intermediate. At higher reaction temperature, reducible oxide supported catalysts, particularly titania, favours deep‐hydrogenated products and higher conversion than non‐reducible oxide supported catalysts. Among all the catalysts, nickel on titania displayed maximum conversion of furfural. TiO₂ possessing higher acidity than ceria, favoured ring‐rearrangement of furfuryl alcohol to cyclopentanone at high temperatures, while the latter retarded reduction of cyclopentanone due to blockage of active‐sites by unreacted furfural and strongly adsorbing intermediates. The combined effects of the electronic‐state of supported metal and surface acidity of catalyst provide a new strategy to tune catalytic properties for selective transformation during hydrogenation of furfural.