Self-Assembly of Lotus-Type Holes Two-Dimensional NiO Nanosheets and Its Efficient Catalytic Property for Styrene Epoxidation

Lotus-type holes two-dimensional NiO nanosheets were fabricated via hydrothermal method followed by calcinations. Three types of surfactants as the structure-directing agent in an ammonia aqueous solution with calcination, only anionic surfactant sodium dodecyl benzene sulfonate (SDBS), non-ionic surfactant polyvinyl pyrrolidone (PVP) can form lotus-type porous NiO nanosheets, cationic surfactant cetyltrimethyl ammonium bromide (CTAB) have no such effect. A series of characterization of the resulting samples revealed that the materials maintained singularly small thickness of only 3-5 nm, lotus root hole diameter 40 nm(SDBS),20 nm(PVP). The formation mechanism of the lotus-type porous two-dimensional morphology is investigated. The as-synthesized NiO without support delivered efficient catalytic property in styrene epoxidation which significantly reduced reaction time. When the catalyst was reused the conversion and selectivity of styrene oxide still remained high.