Oxidation of carbon monoxide over various nickel oxide catalysts in different conditions: A review

•Among the various transitional metal oxide catalysts the nickel oxide (NiO) is one of the best catalysts for CO oxidation at a lower temperature.•The performances of NiO nanoparticles are highly dependent on the crystallite size, surface area and pore volume of the catalysts.•The unique Ni0, Ni2+ and Ni3+ species for the nickel-containing samples are make them better catalytic activity.•The reduction of NiO to Ni0 on the surface, since there was no oxygen in the feed. The low-temperature catalytic oxidation of carbon monoxide (CO) is very important process for all human health protection systems. The major sources of CO produced into the environment are automobile exhaust, so that the various types of catalysts are used in the catalytic converter for oxidation of CO. As compared to noble metal oxide catalysts the transitional metal oxide catalysts are very active, lower cost, easily available and fast regenerated. Among the various transitional metal oxide catalysts the nickel oxide (NiO) is one of the best catalysts for CO oxidation at a lower temperature. A small amount of NiO was deposited on mesoporous Al2O3 using atomic layer deposition and subsequently oxidation at different temperatures. Furthermore, as the pre-annealing temperature increased and improved resistance towards poisoning due to the CO oxidation was observed. The Ni/TiO2 catalyst show that the best efficiency in selectivity, performances and stability in the heterogeneous catalysis. The performances of NiO nanoparticles are highly dependent on the crystallite size, surface area and pore volume of the catalysts. The certain attention has been paid on recovery of Ni nanoparticle catalysts from reaction systems and their reuse for several times without losses of catalytic activity in CO oxidation. This investigation will shown scientific basis for potential design of Ni nano-particle catalysts for CO oxidation.