Kinetics and mechanisms of the hydrogenation of CO2 to methanol on oxide-supported Au catalysts

Abstract

Due to the depletion of fossil fuel reserves, new ways of energy production from renewable sources such as the wind and the sun have to be explored and realized in the near future. The widespread use of renewable energies is possible only with energy storage strategies to even out the fluctuations in supply. Methanol is an ideal energy storage molecule, which could be obtained by the hydrogenation of anthropogenic carbon dioxide and water-based hydrogen.The potential of supported Au catalysts for this reaction was investigated in this study. The Au catalysts were characterized extensively by electron microscopy, low temperature nitrogen adsorption and optical emission spectroscopy. In addition operando techniques such as kinetic and infrared spectroscopy measurements under conditions relevant for industrial applications were applied. The physical and chemical properties of the Au catalysts were correlated with their activity and selectivity for methanol formation. Possible reaction mechanisms and preliminary conclusions on the reaction intermediates could be derived from the measurement results. Overall it has been shown that Au catalysts are attractive alternatives to the industrially used Cu-based catalysts because of their high activity and superior selectivity for methanol formation.