A Review on CO Oxidation Over Copper Chromite Catalyst

CO is a toxic and detrimental air pollutant. It not only affects human beings but also vegetation and indirectly increases global warming. An estimate has shown that vehicular exhaust contributes about 64% of the CO pollution in developed countries. Due to the exponentially increasing number of automobiles on roads, CO concentrations have reached an alarming level in urban areas and regulatory measures had been adopted to curb the menace of vehicular pollution. To control vehicular exhaust pollution, end-of-pipe-technology using noble metals catalytic converters are recommended. The increasing prices of noble metals with the increasing number of vehicles motivates the investigation of material concepts to reduce the precious metal content in automotive catalysts or to find a substitute for noble metals. Among non-noble metals, copper chromite is found to be most promising and exhibits comparable activity for CO oxidation to that of precious metals. Further, low cost, easy availability and advance synthesis methods with stabilizer, promoter, etc. advocates for the use of copper chromite as an auto exhaust purification catalyst. There is a lot of literature available on copper chromite catalyst for CO oxidation, but still there is a gap in the literature for a review article solely devoted to copper chromite catalyst for CO oxidation. Therefore, in an attempt to fill this gap, the present review updates and evaluates the progress and future scope for copper chromite catalyst for purification of exhaust gases of low sulfur contents. The requirement to develop successful methods to reclaim the components of the spent copper chromite catalyst for its safe disposal is also discussed. The paper is useful for people who want to quickly know the state of art and all the aspects concerning the investigated materials. A total of 265 references have been cited.