Catalytic combustion of styrene over copper based catalyst: Inhibitory effect of water vapor

The effects of water vapor on the activity of the copper based catalysts with different supports such as CuO/γ-Al2O3, CuO/SiO2 and CuO/TiO2 for styrene combustion were investigated. The catalytic activity of the catalysts was tested in the absence of and presence of water vapor and the catalysts were characterized. Temperature programmed desorption (TPD) experiments and diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) measurements were conducted in order to estimate and explain the water effects. Results showed that the existence of water vapor had a significant negative effect on the catalytic activity of these copper based catalysts due to the competition adsorption of water molecule. DRIFTS studies showed that the catalyst CuO/γ-Al2O3 had the strongest adsorption of water, while the catalyst CuO/TiO2 had the weakest adsorption of water. H2O-TPD studies also indicated that the order of desorption activation energies of water vapor on the catalysts or the strength of interactions of water molecules with the surfaces of the catalysts was CuO/γ-Al2O3 > CuO/SiO2 > CuO/TiO2. As a consequence of that, the CuO/TiO2 exhibited the better durability to water vapor, while CuO/γ-Al2O3 had the poorest durability to water vapor among these three catalysts.