Mesoporous silica materials with high pore volume were successfully prepared by the chemical precipitation method, with water glass and a biodegradable nonionic surfactant polyethylene glycol (PEG). The obtained materials were characterized by trans-mission electron microscopy (TEM), scanning electron microscopy (SEM), thermo gravimetric analyzer and differential scanning calorimetry (TG-DSC), nitrogen adsorption-desorption measurements, and X-ray diffraction (XRD). The results showed that the changes of the pore parameters depended on both the surfactant content and heat treatment temperature. When the content of PEG was 10wt/ and the obtained PEG/SiO2 composite was heated at 600°C, the mesoporous silica with a pore volume of 2.2 cm3/g, a BET specific surface area of 361.55 m2/g, and a diameter of 2-4 μm could be obtained. The obtained mesoporous silica materials have po-tential applications in the fields of paint and plastic, as thickening, reinforcing, and flatting agents.
Pd-based egg-shell nano-catalysts were prepared using porous hollow silica nanoparticles (PHSNs) as support, and the as-prepared catalysts were modified with TiO 2 to promote their selectivity for hydro-genation of acetylene. Pd nanoparticles were loaded evenly on PHSNs and TiO 2 was loaded on the active Pd particles. The effects of reduction time and temperature and the amount of TiO 2 added on catalytic performances were investigated by using a fixed-bed micro-reactor. It was found that the catalysts showed better performance when reduced at 300°C than at 500 °C, and if reduced for 1 h than 3 h. When the amount of Ti added was 6 times that of Pd, the catalyst showed the highest ethylene selectivity.
In this paper,zinc oxide nanoparticles were first prepared and surface-modified.A Pickering emulsion was then prepared,consisting of nitrobenzene(oil phase),water(water phase)and the modified zinc oxide nanoparticles located on the water-oil interface.The effects of different emulsions on the removal rate of nitrobenzene by photocatalytic degradation were studied.The results proved that use of a Pickering emulsion stabilized by surface-modified ZnO nanoparticles provides an effective and novel way to intensify the photocatalytic degradation of the organic contaminant.
