Preparation and characterization of bulk MoXC catalysts and their use in the reverse water-gas shift reaction

Abstract In this work, different routes for the preparation of molybdenum carbides through sol-gel methods were studied; several parameters such as molybdenum precursor, carbon source and Mo/C ratios were explored. The materials were characterized using different techniques, such as adsorption/desorption of N2, XRD, Raman spectroscopy, SEM-EDX, TEM-EELS, H2-TPR and XPS. Depending on the preparation method used, the presence of different MoxC crystalline phases, Mo2C and/or MoC cubic and/or hexagonal, were determined. The catalytic behaviour in CO2 conversion for CO production through the reverse water gas shift reaction was tested using a reactant mixture CO2/H2 = 1/3 (molar ratio) at 0.1 MPa and a gas hourly space velocity of 3000 h-1. Values of CO2 conversion up to 26 %, with nearly 100 % selectivity to CO were achieved as a function of the reaction temperature and the catalyst used.