Patent ID: 7556787

Claim:
A method for treating an exhaust gas containing fluorine-containing compounds, which comprises the steps of: subjecting the exhaust gas to preliminary treatment whereby the exhaust gas is brought into contact with a metal catalyst carrying a tungsten oxide on an alumina-zirconium composite oxide, thereby partially removing perfluorocarbons (PFCs) and carbon monoxide from the exhaust gas, and then bringing an emission obtained from the preliminary treatment into contact with a γ-alumina catalyst to further remove perfluorocarbons (PFCs) and carbon monoxide from the emission, wherein the γ-alumina has such a crystalline structure that a diffraction line with an intensity of 100 or more appears at the following five diffraction angles 2θ X-ray diffractometer, 33°±1°, 37°±1°, 40°±1°, 46°±1° and 67°±1°.