NiO microspheres with tunable porosity and morphology effects for CO oxidation

Hierarchiral NiO flower-like microspheres with tunable porosity were prepared based on a facile solvothermal method. Three kinds of NiO micro-flowers (NiO-A, NiO-B, and NiO-C) with different porosity have been fabricated mainly by tuning the concentration of nickel nitrate. These flower-like microspheres are comprised of densely packed irregular sheets and display a multi-peaks pore distribution in a wide range in both mesoporous and macroporous regions. The BET surface area of NiO-A, NiO-B and NiO-C is 59.9 m2 g−1, 50.2 m2 g−1 and 15.1 m2 g−1, respectively. The pore volume of NiO-A, NiO-B and NiO-C is 0.2214 cm3 g−1, 0.0829 cm3 g−1 and 0.0549 cm3 g−1, respectively. These NiO spheres show a strong morphology dependant nature for CO oxidation catalysis. Compared to the conventional NiO nanoparticles, these flower-like NiO micro-spheres possess a superior catalytic activity for CO oxidation.