Promotional effects of ruthenium oxide on catalytic oxidation of dichloromethane over the tungsten-titanium binary oxides catalyst

As a promising abatement technology for CVOCs removal, catalytic oxidation has been sent to the spotlight with a great importance to develop suitable catalysts with high activity, high selectivity and long-time stability. In this work, it was found that doping niobium and tungsten into TiO2 could improve activity of the catalysts for catalytic oxidation of dichloromethane and the latter stood out. The W1Ti10Ox catalyst exhibited highest activity below 225 degrees C and was overtaken then by RuO2/W1Ti10Ox as temperature rose (100% dichloromethane conversion and 100% CO2 selectivity at 300 degrees C), which could be attributed to the synergistic effects of acidity and redox ability according to NH3-TPD, Py-IR and H-2-TPR results. In addition, abundant surface active oxygen species and high oxygen mobility also made contribution to the decomposition of dichloromethane. However, distinct deactivation over W1Ti10Ox was observed during the activity and stability tests. Further research went to show that the loss of active components tungsten species, as culprit of the inactivation, was caused by the reaction between tungsten and chlorine. And loading RuO2 could avoid the formation of WClx or WOxCly and the loss of tungsten via Deacon reaction, thereby improving the resistance of Cl-poisoning and stability of the catalysts. (c) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

Catalytic oxidation with TiO2 doped with niobium and tungsten showed high activity in removing dichloromethane, but experienced deactivation due to the reaction between tungsten and chlorine. Loading RuO2 helped prevent this deactivation, improving resistance to Cl-poisoning and stability of the catalysts.