Porous Ni-Co bimetal oxides nanosheets and catalytic properties for CO oxidation

Series of Ni-Co bimetal hydroxides nanosheets have been obtained by tuning the molar ratio of cobalt and nickel in an oleylamine assisted synthetic system. Porous Ni-Co bimetal oxide nanosheets with tunable compositions have been obtained by directly thermal decomposition of corresponding hydroxides at 400 °C. The physicochemical properties of these Ni-Co bimetal oxides have been fully characterized and analyzed. Compared with pure NiO and Co3O4, the bimetal oxides show better catalytic performance for CO oxidation. By increasing Co content in the reaction system, the as-prepared Ni-Co bimetal oxides system can be classified into three different crystal structure types. When Co percentage is less than 20%, the samples display identical cubic crystal structure with pure NiO and possess higher surface area and better catalytic performance than others. As Co percentage in the system is between 40% and 60%, the samples tend to form a stable lamellar structure of NiCo2O4. Co3O4 based crystal structure type of Ni-Co bimetal oxides is observed when Co percentage is more than 80%.