Coupling of propane with CO2 to propylene over Zn-promoted In/HZSM-5 catalyst

Abstract

The ZnIn/HZSM-5 catalyst was prepared by the wetness impregnation method, and the structure of catalyst was characterized by XRD, SEM, TEM, H2-TPR, NH3-TPD, XPS, TG, and N2 adsorption–desorption and then investigated in the coupling of propane with CO2 to propylene. It is found that the addition of Zn species is beneficial to the dispersion of In2O3 over HZSM-5, which plays an important role in propene formation, and adjusts the acidity distribution of In/HZSM-5 catalyst, as well as significantly improves the activity of In/HZSM-5 catalyst. The selectivity of propylene is 68.21% in the coupling of propane with CO2 over ZnIn/HZSM-5 catalyst when the time on stream (TOS) is 2 h, reaction temperature is 580 °C, reaction pressure is 0.3 MPa, C3H6:CO2:N2 = 1:4:5, catalyst mass is 0.2 g, and space velocity is 6000 mL gcat−1 h−1. However, the selectivity of propylene is only 63.33% and 0.25% in the propane dehydrogenation or CO2 hydrogenation reaction, respectively. The ZnIn/HZSM-5 catalyst showed a higher stability with only 0.80% conversion drop after three cycles.