Support effects on direct conversion of ethylene to propylene over Pd-Mo catalysts

摘要

A series of Pd-Mo supported catalysts were prepared and tested in the direct conversion of ethylene to propylene. The relationship between the catalytic performance and support nature was investigated. On basis of XRD data, H_2-TPR, UV-Vis spectra, supports with higher acidity were beneficial for the formation of stable palladium cationic form and highly-dispersed Pd-containing particles that were active in ethylene dimerization. The presence of alumina in the support was required for the dispersion of molybdenum species and for the formation of active metathesis sites. On the optimal MoO_3/PdO/Al_2O_3 catalyst, ethylene conversion reached 24% and propylene selectivity was 64% (70°C, 0.1 MPa, 0.5 h~(-1)).