A Review of Synthesis, Structure and Applications in Hopcalite Catalysts for Carbon Monoxide Oxidation

Carbon monoxide (CO) is a poisonous atmospheric pollutant. It highly affects human beings, plants, animals and environment. Automobile exhaust is the largest source of CO emission in the environment. To control this automobile exhaust pollution, the catalytic converters are used. Many types of catalysts have been investigated for CO oxidation purposes, i.e., noble metal, base metal, rare earth, perovskite, spinel and mixed transient metal oxides. These catalysts are widely used in a catalytic converter. Among the various metal oxide catalysts, hopcalite (CuMnOx) is one of the most efficient catalysts for low-temperature CO oxidation. Hopcalite catalysts have been reported to be good from economical, thermal, activity, selectivity and availability points of view. The activity of hopcalite catalysts is strongly dependent on the surface area, crystallite size and binding energy of the catalysts. This study will provide a scientific basis for designing future application of hopcalite catalysts for low-temperature CO oxidation. This manuscript provides a summary of published information regarding pure and substituted hopcalite catalyst, synthesis methods; properties and application for CO emissions control. A number of papers associated with CO oxidation over the hopcalite catalysts have been available, but no review papers appear in the literature that is dedicated to CO oxidation. Therefore, in an attempt to fill this gap, the present review updates and evaluates the progress and future scope of hopcalite catalyst for purification of exhaust gases.