Changsong Wang

An enhanced CdS/TiO2 photocatalyst with high stability and activity: Effect of mesoporous substrate and bifunctional linking molecule

To accomplish the more effective coupling of cadmium sulfide quantum dots (CdS QDs), the mesoporous TiO2 substrate and bifunctional linker, mercaptopropionic acid (MPA), were used to disperse and stabilize the CdS QDs. Due to the porous nano-architecture on the TiO2 substrate with large surface area and high crystallinity, the efficiency of degradation of organic compounds in aqueous solution under visible light irradiation is greatly enhanced, compared to CdS loaded anatase TiO2 without porous structure and common commercial P25. Furthermore, the bifunctional linking molecule, MPA, could effectively disperse and stabilize CdS nanoparticles. CdS/TiO2 with the linking molecule CdS-MPA-TiO2(m) exhibits much more stability and activity than CdS-TiO2(m) which is prepared by direct deposition. After 3 cycling tests of degradation of MB (methylene blue), the loss ratio of CdS on CdS-TiO2(m) is 70.6%, much larger than that of 17.8% on CdS-MPA-TiO2(m). This work may give ideas for the synthesis of other stable and active supported catalysts in many fields.

Simple physical approach to reducing frictional and adhesive forces on a TiO2 surface via creating heterogeneous nanopores.

A simple physical strategy to reduce the frictional and adhesive forces on TiO(2) films was proposed by constructing mesoporous TiO(2) films with heterogeneously distributed nanopores on the film surfaces. In comparison, TiO(2) films with densely packed nanoparticles were also prepared. The crystal structure and morphology of the films were characterized with Raman spectroscopy, field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM). It was found that the TiO(2)(B) phase exists in the mesoporuos TiO(2) films but not in the densely packed films. The existence of TiO(2)(B) plays a significant role in creating and maintaining the nanopores in the mesoporous TiO(2) films. The frictional and adhesive forces were measured on both films using AFM. The mesoporous films exhibit two typical adhesion forces of around 3 and 12 nN in the force distribution profile whereas the densely packed films show only one around 12 nN. The frictional coefficients were 2.6 × 10(-3) and 6.7 × 10(-2) for the mesoporous and densely packed TiO(2) films, respectively. A model based on the atomic structures of a thin film of water molecules adsorbed on TiO(2) surfaces leading to hydrophobic effects was proposed to understand the lower frictional and adhesive forces observed on the mesoporous TiO(2) films. This simple physical approach to reducing the frictional and adhesive forces on TiO(2) films could have broad applications to a variety of surface coatings.

Review on heat-utilization processes and heat-exchange equipment in biogas engineering

With the increasing demand for environmental protection and renewable energy, bioenergy technology has been attracting considerable attention. Anaerobic digestion (AD) is the process to convert the ...

Thermal Stability of Gold Catalyst Supported on Mesoporous Titania Nanofibers

By deposition-precipitation with urea method, gold was loaded on mesoporous TiO2 whisker, which was prepared from a potassium titanate whisker precursor through solid phase sintering process. The morphology and structure of these as-prepared catalysts were characterized by N2 adsorption-desorption, X-ray diffraction, and transmission electron microscopy. The reduction of 4-nitrophenol to 4-aminophenol by NaBH4 was evaluated as a probe reaction. After calcination at high temperature, the activity of the catalysts supported on mesoporous TiO2 nanofiber was well maintained, and the particle size of gold nanoparticles was hardly changed. This might be attributed to the peculiar crystallographic structure and mesoporous nanoarchitecture of the mesoporous TiO2 whisker.

Wetting Behaviors of Ethanol/Water on Rough PTFE Surface

Abstract The wetting behaviors of ethanol/water solutions with different surface tensions were studied on the rough superhydrophobic polytetrafluoroetylene (PTFE) coating. Air fraction was calculated using Cassie equation, and the forces were compared. The result indicated that the ethanol/water solutions gradually filled in the multilevel structures of the PTFE coating with the decrease in the surface tension. Only the stripe structure was filled when the surface tension was greater than 28 mN·m −1 . When the surface tension was less than 28 mN·m −1 , the papillary structure was also filled. Because it has little contribution to the air fraction, the surface could not be wetted when the stripe structure was filled. However, the surface could be wetted by the solutions when the papillary structure, which had a considerable contribution to the air fraction, was filled.

Adjusting the rheological properties of corn-straw slurry to reduce the agitation power consumption in anaerobic digestion

Agitation power consumption (P) in the anaerobic digestion of biogas plants is a major consumer of electric energy. To reduce P by adjusting the rheological properties, in this work, the rheological properties of the corn-straw slurry were studied systematically considering the effects of TS, temperature and particle-size, and P was calculated based on the rheological behavior of the corn-straw slurry. The investigation shows that the corn-straw slurry is a non-Newtonian fluid and exhibit shear-thinning behavior, and the rheological properties can be well described with the power law model. The size-reduction is more effective compared to the option of temperature-increase to improve the agitation power efficiency, and the value of P can be reduced by up to 48.11%. Since the size-reduction can also increase the methane yield, the reduction of the particle-size is a promising option to save P, especially at relatively high TSs and for the thermophilic AD process.