Supported Nanostructured MoxC Materials for the Catalytic Reduction of CO2 through the Reverse Water Gas Shift Reaction

MoxC-based catalysts supported on gamma-Al2O3, SiO2 and TiO2 were prepared, characterized and studied in the reverse water gas shift (RWGS) at 548-673 K and atmospheric pressure, using CO2:H-2 = 1:1 and CO2:H-2 = 1:3 mol/mol reactant mixtures. The support used determined the crystalline MoxC phases obtained and the behavior of the supported nanostructured MoxC catalysts in the RWGS. All catalysts were active in the RWGS reaction under the experimental conditions used; CO productivity per mol of Mo was always higher than that of unsupported Mo2C prepared using a similar method in the absence of support. The CO selectivity at 673 K was above 94% for all the supported catalysts, and near 99% for the SiO2-supported. The MoxC/SiO2 catalyst, which contains a mixture of hexagonal Mo2C and cubic MoC phases, exhibited the best performance for CO production.