Xianghai Tang

Selective synthesis of anatase and rutile via ultrasound irradiation

A simple and efficient methodology has been established for the selective synthesis of anatase and rutile as well as their mixtures with various precursors using ultrasound irradiation; the products, the particle sizes of which are nanometric (<9 nm), are dependent both upon the reaction temperature and the precursor used; a substantial reduction in reaction time as well as reaction temperature is observed as compared to the corresponding hydrothemal processes.

Using Sonochemical Methods for the Preparation of Mesoporous Materials and for the Deposition of Catalysts into the Mesopores

Ultrasound radiation can be used to synthesize a variety of mesporous materials. The reaction time is considerably shorter than the conventional methods. Ultrasonic waves can be further used for the insertion of amorphous nanosized catalysts into the mesopores. A detailed study demonstrates that the nanoparticles are deposited as a monolayer on the inner mesopores walls without blocking them. When the ultrasonically prepared catalyst/mesoporous-subtrate composite is used in catalysis a high conversion into product is obtained.

Synthesis of carbon nanoflasks

The catalytic reaction of Co(CO)3NO and Mg at 900 °C has led to the formation of multi-walled carbon nanoflasks.

Rapid synthesis of high quality MCM-41 silica with ultrasound radiation

High quality MCM-41 silica with thick walls and a very narrow distribution of mesopore size has been synthesized in a relatively short time via ultrasound radiation.

Interaction between Ti-gel and silver, copper, as well as nickel compounds under ultrasound irradiation

Ag-TiO2, Cu-TiO2 and Ni-TiO2 were prepared by sonication. The interactions of Ti-gel with silver, copper and nickel ions under ultrasound irradiation are very different, although these ions can be dispersed very well in titania. The results of EDXA and XRD analysis indicate that Ti-gel does not react with AgCl and crystallizes unaffectedly to form rutile. M(OH)2 (M = Cu and Ni), on the other hand, favors polycondensation with Ti-gel and affects the crystallization of Ti-gel. CuO favors stabilization of the anatase phase. Ni2+ ions tend to incorporate more easily into titania than Cu2+ ions do when the samples are calcined. TEM, and BET were also used to characterize the samples.