Porous MoxCy/SiO2 material for CO2 hydrogenation

Abstract

The synthesis and characterization of an inexpensive porous MoxCy/SiO2 material is presented, which was obtained by mixing ammonium hexamolybdate, sucrose, and a mesoporous silica (SBA-15), with a subsequent heat treatment under inert atmosphere. This porous material presented a specific surface area of 170 m2/g. The catalytic behavior in CO2 hydrogenation was compared with that of Mo2C and α-MoC1−x obtained from ammonium hexamolybdate and sucrose, using different Mo/C ratios. CO2 hydrogenation tests were performed at moderate (100 kPa) and high pressures (2.0 MPa), and it was found that only CO, H2O and CH4 are formed at moderate pressures by the three materials, while at higher pressures, methanol and hydrocarbons (C2H6, C3H8) are also obtained. Differences in selectivity were observed at the high pressure tests. Mo2C presented higher selectivity to CO and methanol compared with MoC1−x, which showed preferential selectivity to hydrocarbons (CH4, C2H6). The porous MoxCy/SiO2 material showed the highest CO2 hydrogenation activity at high temperatures (270 and 300 °C), being a promising material for the conversion of CO2 to CO and CH4.