Oxygen vacancies enriched Nb-WOX supported Ru for polychlorinated aromatics oxidation: Reaction mechanism exploration

The current catalysts for polychlorinated aromatics (PCAs) oxidation showed either poor low-temperature catalytic activity, low mineralization ability or bad stability, and developing oxygen vacancies enriched catalysts with abundant acid sites is a potential solution for the above drawbacks. Herein, oxygen vacancies enriched Nb-WO X were developed for o -DCB ( o -dichlorobenzene, a PCAs model compound) oxidation, and they showed notably better low-temperature catalytic activity with T 50% <350 °C than did commercial WO 3 (T 50% >400 °C) under the WHSV of 36000 mL g −1 h −1 . Nb-WO X supported Ru exhibited even lower T 50% (173 °C) and T 90% (238 °C), as well as high CO X yield with >99% ratio of CO 2 to CO and good stability (>99% conversion for 500 mins) when with 1.5 wt% Ru loading at 300 °C. The above phenomenon was attributed to the abundant oxygen vacancies and acid sites in Nb-WO X that contributed to the better redox property, stronger interaction with Ru species and the removal of accumulated chloride. The o -DCB oxidation mechanism revealed that the higher CO 2 ratio to CO on Ru/Nb-WO X arose from the deep oxidation of CO byproducts. The work described here will instruct us to degrade PCAs effectively through catalysts design.