화학공학소재연구정보센터
Catalysis Today, Vol.309, 43-50, 2018
Second metals (Lanthanum, Cerium, and Yttrium) modified W/SiO2 catalysts for metathesis of ethylene and 2-butene
Lanthanum, cerium, and yttrium were added as a second metal on the WO3/SiO2 catalysts by the incipient wetness impregnation method with the atomic ratio between the second metal and tungsten 0.083 in order to improve the catalytic performances of W-based catalysts in the metathesis of ethylene and 2-butene. As revealed by various characterization results from X-ray diffraction, nitrogen physisorption, inductively coupled plasma optical emission spectrometry, ion-exchange titration, FT-Raman, ammonia temperature programmed desorption (NH3-TPD), and reactant-TPD, the dispersion of tungsten and adsorption properties were significantly improved by adding of the second metals, especially the adsorption of the mixed cis/trans-2-butene isomers. Hence, their catalytic performances were higher than the non-modified one when mixed cis/trans-2 butene isomers were used as the feeds. In addition, the presence of La as the second metal could also reduce coke formation on the catalysts probably by decreasing the ensemble site effect.