Carbon dioxide hydrogenation over supported Au nanoparticles: Effect of the support

Abstract The present work aims to explore the impact of the support (M x O y : Al 2 O 3 , TiO 2 , Fe 2 O 3 , CeO 2 , ZnO) on the CO 2 hydrogenation activity of supported gold nanoparticles (Au/M x O y ) at atmospheric pressure. The textural, redox and surface properties of Au/M x O y catalysts were evaluated by various characterisation methods, namely N 2 adsorption-desorption at −196 °C, temperature-programmed reduction in H 2 , high resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The results revealed a strong influence of the support both on CO 2 conversion and on products distribution. Gold nanoparticles supported on ZnO and CeO 2 were highly selective towards methanol. TiO 2 - and Fe 2 O 3 -based samples demonstrated high CO 2 conversion, leading, however, almost exclusively to CO and/or CH 4 . Au/Al 2 O 3 was practically inactive in the investigated temperature range (200–350 °C). The following activity order, in terms of methanol formation rate, was obtained: Au/CeO 2  > Au/ZnO > Au/Fe 2 O 3  > Au/TiO 2  > Au/Al 2 O 3 . Au/CeO 2 exhibited a methanol formation rate of 4.1 × 10 −6  mol s −1  g Au −1 at 250 °C, which is amongst the highest reported at ambient pressure, in spite of the chemical inertness of bare ceria. In view of the characterisation results, the superiority of the Au/CeO 2 sample could be mainly ascribed to a synergistic effect linked to the Au-ceria interactions.