Sonochemically prepared Pt, Au and Pd nanoparticles were successfully immobilized onto TiO2 with the assistance of prolonged sonication. Their photocatalytic activities were evaluated in H2 production from aqueous ethanol solutions. Beside the sonochemical method, the conventional impregnation method was also employed to prepare photocatalysts. The sonochemically prepared catalysts showed higher activities than did the conventional ones. Their photocatalytic activities depended on the work functions and the dimensions of supported noble metal nanoparticles. Smaller Pt nanoparticles effectively restricted recombination of electrons and holes and provided H2 at a higher rate.

Gold(III) (tetrachloroaurate(III)) was reduced in an aqueous solution containing only a small amount of 2-propanol to form colloidal gold nanoparticles in a standing wave system generated by a 200 kHz ultrasonic generator. The rates of gold(III) reduction and the sizes of the formed gold particles could be sonochemically controlled by controlling the irradiation parameters such as the temperature of the solution, the intensity of the ultrasound, and the positioning of the reactor. The size of gold particles strongly depended on the rate of gold(III) reduction, suggesting that the rate of gold(III) reduction affects the initial nucleation of the gold particles.

Palladium nanoparticles dispersed on Al2O3 were prepared via the sonochemical reduction of tetrachloropalladate(II) (Pd(II)) in an aqueous solution. The reduction of Pd(II) to metallic Pd successfully proceeded, even in the presence of Al2O3 powder, by ultrasonic irradiation at 200 kHz. The rates of Pd(II) reduction strongly depended on the type of alcohol additive, which acts as an effective accelerator for Pd(II) reduction. The dispersion of metallic Pd particles on the Al2O3 surface was appreciably enhanced by increasing the rate of reduction. By UV−visible, pH, and transmission electron microscopy measurements, the major pathway in the formation of Pd nanoparticles on Al2O3 was speculated to proceed via the following three steps:  (1) the reduction of Pd(II) ions proceeds with reducing radicals formed by sonolysis of water and alcohol molecules, resulting in the formation of Pd nuclei, (2) the growth and/or the agglomeration of the Pd nuclei rapidly occurs to form Pd nanoparticles, and (3) the Pd particles are simultaneously adsorbed onto the Al2O3 surface. The catalytic activities of the Pd nanoparticles prepared by sonochemical reduction were investigated for the hydrogenation of olefins at room temperature. The rates of hydrogenation over these catalysts were much higher than those over a conventionally prepared Pd/Al2O3 catalyst and a commercially available Pd black.

Ten derivatives (3-12) of marine alkaloid lamellarin D (1) were synthesized and evaluated for cytotoxicity against a HeLa cell line in an effort to examine their structure-activity relationships. It appeared that the hydroxyl groups at positions C-8 and C-20 of 1 were important structural requirements for cytotoxic activity, while the hydroxyl group at C-14 and the two methoxy groups at C-13 and C-21 were not necessary for the activity.