In this paper, ZnO nanoparticle photocatalysts were modified by depositing Pd on their surfaces with a photoreduction method. We mainly investigated the modification mechanisms as well as the effects on the photocatalytic activity of ZnO nanoparticles of deposited Pd by means of XPS and SPS (Surface Photovoltage Spectroscopy), and the effects of Pd content on SPS responses were also discussed from the point of the electronic energy level. The results showed that the content of crystal lattice oxygen on the surface of ZnO nanoparticle decreased after an appropriate amount of Pd was deposited, while that of adsorbed oxygen increased, indicating that Pd was mainly deposited on the crystal lattice oxygen. At the same time, the intensity of SPS responses of ZnO nanoparticles remarkably decreased. In addition, the activity of ZnO nanoparticles could be greatly improved by depositing an appropriate amount of Pd in the gas phase photocatalytic oxidation of n-C7H16. Thus, it could be concluded that the increase in surface content of adsorbed oxygen could facilitate the photocatalytic reaction, and there were close relationships between the SPS response and photocatalytic activity, i.e. the weaker the SPS response, the higher the photocatalytic activity, of Pd-deposited ZnO nanoparticles.

Ag-TiO2 catalysts with different Ag contents were prepared via a sol-gel method in the absence of light. Based on the characterizations of XRD, photoluminescence (PL), surface photovoltage spectroscopy (SPS), field-induced surface photovoltage spectroscopy (FISPS), and XPS as well as the evaluation of the photocatalytic activity for degrading rhodamine B(RhB) solutions, it was found that the Ag dopant promoted the phase transformation as well as had an inhibition effect on the growth of anatase crystallite. The PL and SPS intensities were decreased with increasing Ag content, indicating that the Ag dopant could effectively inhibit the recombination of the photoinduced electrons and holes. However, the active sites capturing the photoinduced electrons reduced, while the Ag content exceeded 5mol%. At rather low Ag dopant concentrations, the migration and diffusion of Ag+ ions were predominant, while at rather high Ag dopant concentrations, the migration, diffusion, and reduction of Ag ions simultaneously occurred. The Ag-TiO2 photocatalysts with appropriate content of Ag (Ag species concentration is from about 3 to 5mol%) possessed abundant electron traps so as to be favorable for the separation of the photoinduced electron-hole pairs, which could greatly enhance the activity of the photocatalysts. From the results of FISPS measurements, it could be found that the impurity bands and abundant surface states were introduced into the interfacial layer of TiO2 because of Ag simultaneously doping and depositing, which could improve the absorption capability for visible light of the photocatalysts.

In this paper, we examined the lifetimes of made-in-home ZnO and TiO2 nanoparticles in the gas phase photocatalytic oxidation of n-C7H16 or SO2, and especially investigated the deactivation mechanism by utilizing surface photovoltage spectrum (SPS) and X-Ray photoelectron spectroscopy (XPS) testing techniques and by considering semiconductor chemical properties. The results showed that ZnO could almost be deactivated in the gas phase photocatalytic oxidation of n-C7H16, while TiO2 could keep most of its activity. In the gas phase photocatalytic oxidation of n-C7H16 or SO2, ZnO and TiO2 both could almost be deactivated. The deactivation mainly resulted from semiconductor surface conduction type change from N-type before the photocatalytic reaction to P-type after the deactivation because of the adsorption of the oxidation products such as H2O, CO2 and SO3 on the semiconductor photocatalyst surface. In addition, the activity of the deactivated photocatalyst could be regenerated to a nearly full extent by washing and drying.

The three-dimensional (3D) accessible pore structures (Im3hm space groups) of continuous mesoporous silica SBA-16 thin films have been prepared by a dip-coating technique in nonaqueous media under acidic conditions on indium-tin oxide glass (ITO). The films are oriented with the (111) crystal plane perpendicular to the surface of the film. On one hand, deposition of iron metal into the mesopores of SBA-16 films was achieved by using an electrochemical method. The Fe2O3 nanowire arrays were synthesized. The crystalline structures of porous Fe2O3 nanowires and nanorods were studied via TEM, SEM, and XRD. On the other hand, a small amount of Fe was deposited into the pores of the SBA-16 thin film as a catalyst, and carbon nanotube arrays formed inside the pores of SBA-16 film were fabricated by catalytic decomposition of acetylene at 700℃. The second-order template synthesis method for preparing the ordered array of carbon nanotubes filled with Fe has been used. The carbon nanotubes are very uniform in diameter and length and are aligned vertically with respect to the SBA-16 film.

A singlet potential energy surface (PES) of the [Si,N,C,S]+ system is investigated by means of MP2 and QCISD(T) (single-point) methods. Four linear isomers of [Si,N,C,S]+ system are found to be kinetically stable and should be experimentally observable. The linear isomer SiNCS+ is the thermodynamically most stable, followed by SSiCN+, SSiNC+ and SiCNS+. No cyclic kinetically stable isomers are found. For the isomer SiNCS