The Mn?Zr composite oxides were prepared by co?precipitation,loading with noble metals(Ru,Pd,Pt) on the surfaces by a following impregnation method.The effects of noble metals on catalytic combustion of vinyl chloride (VC) were further investigated.The structure and chemical state,the oxidation?reduction ability and acidity,the distribution of acid over the noble metal loading catalysts were studied.Noble metals exist in the form of oxidation state on catalyst surface to promote the reduction of Mn?Zr composite oxides and improve the redox ability of the catalysts. In addition,noble metals not only increased total acid amount but also changed the distribution of Br?nsted and Lewis acid centers on catalyst surface.Therefore, the noble metal made the completely VC conversion temperature shift to lower temperature.However,the activities of noble metals for catalytic combustion of VC varied with the kind of noble metal.Among them,Ru had the more positively activity enhancement than that of Pd and Pt.The catalytic temperatures were 206 and 243 °C, when the VC conversion over Ru/MZ(Ru/Mn_0.7Zr_0.3O_x) reached to 50% (t₅₀) and 90% (t₉₀),respectively,which were 69 and 71 °C lower than that using Mn?Zr composite oxide.Meanwhile,the loading of noble metals also changed the composition of chlorinated by?products and reduced their concentration.The total concentration of chlorinated by?products over Ru/MZ catalyst was only 5.7 μL/L with 90% VC conversion rate,which was 70% lower than MZ composite oxide at the same conversion rate.