Total Oxidation of Methane at Low Temperature over Pd/TiO_2-Al_2O_3: Effects of Supports and Residual Chlorine Ions

摘要

Methane is an attractive fuel because of its low carbon to hydrogen ratio and easy availability of natural gas around the world. However, it is also found to be a strong greenhouse gas. Catalytic total oxidation of methane is an effective way to use methane as an energy source or prevent it from polluting the atmosphere. Many kinds of catalysts have been extensively studied for this purpose. Among which palladium-based catalysts offer the highest activity at low temperatures. A lot of studies were devoted to palladium-based system, but there are still uncertainties to explain the influence of some effects such as the pre-treatment history, metal dispersion, residual chorine ions etc, on the catalytic behaviour of the catalyst. In the present work, titania-alumina supported palladium catalysts were investigated by using XRD, XPS, TPR, and ~(18)O_2 isotope exchange technologies with an aim to know more about the nature of the active sites.