An isotopic strategy to investigate the role of water vapor in the oxidation of 1,2-dichloroethane over the Ru/WO3 or Ru/TiO2 catalyst

Electron paramagnetic resonance, in situ diffuse reflection infrared Fourier transform spectroscopy, and temperature-programmed techniques by means of the isotopic trace strategies were used to investigate the effects of water vapor on oxygen species, reaction pathways, byproducts distributions, and accumulation of the chlorine and carbon species on the catalyst surface for 1,2-dichloroethane oxidation over Ru/WO3 or Ru/TiO2 catalyst. The introduction of water vapor produced the OOH species that were converted into more active oxygen (O2– and O−) species. The mulliken population analysis indicates that βC and αC in VC are bonded with H and nucleophilic oxygen of −OH in sequence, respectively, which proved that water directly promoted the transformation of vinyl chloride to CH3COOH. Besides, water could be partially adsorbed at the hydroxyl groups on the Ru/WO3 sample surface, which were provided the adsorption sites for 1,2-dichloroethane molecules. However, the severe competitive adsorption on the surface of Ru/TiO2 resulted in insufficient oxygen adsorption to supplement the oxygen vacancy.