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The hydrolysis of p-nitrophenyl picolinate (PNPP) catalyzed by two nickel (II) complexes (bis(O,O’-di(2-phenylmethyl) dithiophosphate) nickel(II) (NiR1) and bis(O,O’-di(2-phenylethyl) dithiophosphate) nickel(II) (NiR2)) was investigated kinetically in this work. The results indicate that both metal complexes accelerate the hydrolysis of PNPP dramatically and the NiR1 exhibits higher catalytic function on PNPP hydrolysis in the buffered solution with relatively low pH values, while NiR2 shows slightly more efficacy on hydrolysis of PNPP in relatively high pH buffered solutions. This variance is ascribed to the synergism effect of space hindrance of the complexes and the nucleophilic attack of metal-hydroxy species generated by the complexes.

Well-dispersed CeO2 nanoparticles were successfully prepared in a simple system composed of sodium bis (2-ethylhexyl) sulfosuccinate (AOT)- octane-water (W/O) microemulsion in this paper. The morphology and microstructure of the products were characterized by the laser particle size analyzer, Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD), differential scanning calorimeter (DSC) and transmission electron microscope (TEM). It was found that the CeO2nanoparticles obtained from this method have well-proportioned size distributions; the surfactant (AOT) molecule was adsorbed on the surface of CeO2nanoparticles precursor, which is favorable for the dispersion of CeO2nanoparticles; the CeO2nanoparticles calcined was a crystal of the cubic structure. In addition, the mechanism on the formation of the CeO2nanoparticles was also proposed in this paper.