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In this paper, Sn-doped TiO 2 nanoparticles were prepared by a sol–gel method, and also were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared spectrum (IR), ultraviolet–visible diffuse reflection spectrum (UV–vis DRS), photoluminescence spectrum (PL), surface photovoltage spectroscopy (SPS) and electrical field induced surface photovoltage spectroscopy (EFISPS). The sample activity was evaluated by photocatalytic oxidation reactions of phenol solution. The effects of thermal treatment temperature and Sn amount on photoinduced charge property, mainly involving charge separation and bound excitons resulting from surface states, and photocatalytic activity of TiO 2 nanoparticles were principally investigated. The results show that an appropriate calcination temperature and Sn dopant amount can greatly enhance the SPS responses of TiO 2 nanoparticles related not only to the band–band transitions but also to the bound excitons, and obviously weaken the PL signal, while the photocatalytic activity remarkably raises. These demonstrate that the separation rate of photoinduced charges of TiO 2 nanoparticles can be effectively improved by doping Sn, which is responsible for the obvious increase in the photocatalytic activity. Moreover, the existence of bound excitons related to surface states also favor the photocatalytic activity. In addition, it can be found that the SPS responses related to the bound excitons could easily exhibit in the TiO 2 sample consisting of much of anatase and little of rutile, which is possibly ascribed to the heterojunction between the anatase and rutile phase.

The ZnO quantum dots (about 3 nm in average size) and the ZnO nanorods (about 80 nm in length and 14 nm in width) were synthesized by the sol−gel method. They were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), UV−vis spectroscopy, and photoluminescence (PL) spectroscopy. The surface photovoltage (SPV) of ZnO nanoparticles was investigated by means of surface photovoltage spectroscopy (SPS) and field-induced surface photovoltage spectroscopy (FISPS), and the bands were identified. The results show that the SPV of ZnO nanoparticles are greatly different for their different sizes as a result of the quantum confinement effect. The ZnO quantum dots exhibit marked quantum confinement properties; that is, FISPS takes a high symmetry in the changes of the response intensity with the strengthening of the two opposed electric fields, and the FISPS response band always appears at about 369 nm, no matter what external electric field is applied. Whereas for the ZnO nanorods a...

Summary form only given. The conjugated organic ultra-thin films of 2,2-bithiophene(PT), 3-methythio-phene (PMT) and 3-bromothiophene (PBrT) are prepared dy electrochemical polymerization. The electrochemical properties of the single layer films well studied. And the absorption spectra of the films in reduction and oxidation conditions were measured respectively. The data of thermo-emf confirmed that the film of PBrT is p-type behaviore, while the films of PT and PMT exhibited the feature of weak donor. The single-layer and bilayer film cells, with ITO/polymer/Au and ITO/polymer1/polymer2/Au sandwich structure, were composed of PT, PMT and PBrT. No distinct reatifying behaviore was observed all of the single-layer film cells. This fact suggests that there should be no any juction or Schottky berrier between ITO and polymer or Au and polymer interface. The bilayer film cells, e.g. ITO/PBrT/PMT/Au and ITO/PBrT/ PT/Au, show excellent rectifying ability similar to a p-n junction diode and some extent of photo-electric conversion. The rectifying ratio reach about 200. However, the cells of ITO/PT/PBrT/Au and ITO/PMT/PBrT did not show rectifying characteristic. The phenomenon should be attributed to the overoxidation during electropolymerization.

Consider the irrecoverable energy dissipation in fatigue damage process and take the cycle-dependence into account, a fatigue damage model has been proposed. Comparisons have been done between the estimated results by this model and several usual ones with test results.

The cyclic hysteresis energy of four kinds of steel was analysed using fully reversed constant-strain-controlled fatigue tests. Mathematical formulae for the cyclic hysteresis energy of the materials, which have different cyclic properties, are proposed. Because of the experimental and theoretical relations of cyclic hysteresis energy and the total absorbed energy to failure versus fatigue failure life, it is considered that part of the hysteresis energy is absorbed through heating, vibration and non-propagating defects during the process of fatigue life. The total absorbed energy to failure is associated with the variation of cyclic hysteresis energy.

The paper reports the studing results of hydrogen production by photocatalytic decomposition of liquid water over catalysts made up of Co 3 O 4 -doped SrTiO 3 powder under UV irradiation. The results indicated that the photocatalysts have rather high activity of photogenerating H 2 in alkali solution. A strong concentration dependence of OH − is observed for the rate of H 2 formation. Reduction pretreatment of the photocatalysts by H 2 is unfavourable for the H 2 production, but an oxidation pretreatment by O 2 may improve appreciably the catalytic efficiency. The photocatalysts can maintain a stable rate of H 2 production for 9 hrs. Using SPV technique and ESR, we found that the photocatalysts have band-gap surface states near and above valence band of SrTiO 3 which may associate with surface cobalt ions. It has been proposed that the surface states play a key role in charge separation and transfer processes. At the same time, the photocatalytic efficiency and mechanistic aspects are discussed.