NiCo 2 O 4 nanoneedle-assembled hierarchical microflowers for highly selective oxidation of styrene

NiCo2O4 nanoneedle-assembled microflowers have been prepared by a facile one-pot hydrothermal route. The NiCo2O4 microflowers have a well-defined three-dimensional (3D) hierarchical mesoporous structure. When used as catalysts for the styrene oxidation, the 3D NiCo2O4 microflowers show a markedly high styrene conversion of 99% and a high selectivity of 80% to styrene oxide (SO). In addition, the NiCo2O4 catalysts exhibit good recycling stability. The excellent catalytic performance of the NiCo2O4 catalysts can be owing to the numerous surface active sites caused by the 3D hierarchical mesoporous structure and the possible synergistic effect between nickel and cobalt ions.