Characterization and Reaction Performance of the Ru-CrOx/Al2O3 Catalyst for the Oxidative Decomposition of Trichloroethylene

Abstract

As the catalyst for the oxidative decomposition of trichloroethylene (TCE) in air, series of Ru-promoted CrOx/Al2O3 were prepared and studied. The catalysts were characterized using temperature programmed reduction (TPR), temperature programmed desorption of ammonia (NH3-TPD), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Ru-promoted effects were determined in the respects of the initial catalytic activity, the rate of catalyst deactivation, and the product concentrations of CO and Cl2 under dry or wet air conditions. The presence of a small amount of Ru as much as 0.4 wt% in a CrOx/Al2O3 catalyst turned out to promote the catalytic activity and improve the catalytic reaction performance. The Ru(0.4)Cr(9.6) catalyst was characterized to have better reducibility at lower temperature and higher fraction of more active Cr(VI) species over the catalyst surface. This Ru-promoted catalyst proved to be much less subject to the deactivation during the reaction and to produce less concentration of CO than the Cr(10). Such performance improvements of the Ru(0.4)Cr(9.6) catalyst was thought to attribute to its enhanced oxidation activity originated from the well dispersed coexisting Ru-oxide species, possibly being directly involved in the reaction as active centers activating molecular oxygen, and subsequently, facilitating the supply of activated oxygen to the reaction system.