Direct synthesis of LPG from carbon dioxide over hybrid catalysts comprising modified methanol synthesis catalyst and β-type zeolite

Hydrogenation of carbon dioxide to C-3 and C-4 paraffins (LPG) was studied by using hybrid catalysts composed of Zr-modified Cu-Zn catalyst with Pd-modified beta. zeolite. Various factors that affect catalyst activity, including reaction temperature, space velocity, pressure, and the ratio of H-2 to CO2 were investigated thoroughly. The hybrid catalysts exhibited stable activity over 100 h and extraordinary high selectivity of LPG synthesis (especially iso-butane) even under low temperature (260 C) and low pressure (2 MPa). Conversion of CO2 and the yield of hydrocarbon reached 25.2% and 13.3%, respectively, while keeping the selectivity of LPG and CH4 75% and 1%, respectively. The iso-butane/n-butane ratio was about 16/1, whose value was much higher than that of thermodynamic equilibrium (about 1/1). (C) 2014 Elsevier B.V. All rights reserved.