Ru-Ti Oxide Based Catalysts for HCl Oxidation: The Favorable Oxygen Species and Influence of Ce Additive

Several Ru-Ti oxide-based catalysts were investigated for the catalytic oxidation of HCl to Cl-2 in this work. The active component RuO2 was loaded on different titanium-containing supports by a facile wetness impregnation method. The Ru-Ti oxide based catalysts were characterized by XRD, N-2 sorption, SEM, TEM, H-2-TPR, XPS, and Raman, which is correlated with the catalytic tests. Rutile TiO2 was confirmed as the optimal support even though it has a low specific surface area. In addition to the interfacial epitaxial lattice matching and epitaxy, the extraordinary performance of Ru-Ti rutile oxide could also be attributed to the favorable oxygen species on Ru sites and specific active phase-support interactions. On the other hand, the influence of additive Ce on the RuO2/TiO2-rutile was studied. The incorporation of Ce by varied methods resulted in further oxidation of RuO2 into RuO2+ and a modification of the support structure. The amount of favorable oxygen species on the surface was decreased. As a result, the Deacon activity was lowered. It was demonstrated that the surface oxygen species and specific interactions of the Ru-Ti rutile oxide were critical to HCl oxidation.