Selective hydrogenation of acetylene on palladium catalysts supported on sol vothermal-derived titanium dioxide

Abstract

In this study, nanocrystalline titanias have been prepared by thermal decomposition of titanium (IV) n-butoxide in two different solvents (toluene and 1, 4-butanediol) at 320 ํC and employed as supports for Pd and Pd-Ag catalysts for selective acetylene hydrogenation. The titania products obtained from both solvents showed only anatase phase with similar crystallite sizes and BET surface areas. However, due probably to the different crystallization pathways, the number of Ti[subscript 3+] defective sites as shown by ESR results of the titania prepared in toluene were much higher than the ones prepared in 1,4-butanediol. It was found that the use of anatase titania with higher Ti[subscript 3+] defective sites as a support for Pd catalysts resulted in lower activity and ethylene selectivity in selective acetylene hydrogenation. However, this effect was suppressed by Ag promotion.