ABSTRACT
A catalyst is a substance that can change the rate of a chemical reaction but remain unaltered by that reaction. Though a catalyst may speed up a reaction, it never changes the reaction products. Catalysts can be used to oxidize volatile organic compounds (VOCs) at temperatures much lower than required with thermal oxidation. In solid catalyzed reactions, the presence of catalyst surface in the proximity of reactive gas molecules promotes reaction. With porous catalysts, reaction occurs at the gas-solid interfaces, both at the outside boundaries and within the pores themselves. At low temperatures, the reaction is kinetically limited and any oxidation or conversion that occurs is dependent on interaction of the hydrocarbon and oxygen molecules at the catalyst surface. The washcoat is a material coated onto the catalyst substrate to provide a very high surface area support for the catalyst. This washcoat may contain oxides of aluminum, zirconium, transition metals, nickel, titanium, vanadium, cerium, or other metals.
