TiO2 treated in hydrogen atmosphere showed enhanced photocatalytic activity in degrading the sul-fosalicylic acid (SSal). The results of the electrochemical impedance spectroscopy (EIS) investigation showed that the diameters of the capacitive arcs for the H-TiO2 were much smaller than those of bare TiO2 and thermally treated TiO2 in air, indicating that the charge transfer of the H-TiO2 occurs more rapidly, thus inviting a higher photocatalytic activity. When an external bias was applied on the H-TiO2, the arc of the EIS Nyquist plot decreased obviously than without the bias, suggesting more efficient separation of the photo-generated carriers.

研究无水条件下气相三氯乙烯（TCE）的光催化降解反应及其机理，结果表明三氯乙烯的降解产物为HCl、CO2及Cl2，光催化降解速率方程符合Langmuir-Hinshelwood公式，提出了无水条件下TCE的光催化降解机理为空穴直接氧化机理。

The photocatalytic degradation of gaseous trichloroethylene (TCE) without water has been studied. The degradation products were determined to be CO2. HCl and Cl2, and the reaction stoichiometr\,h v was described as C2HCI3+ 2O2hv→HO2 HCI+2C0, +Cl2,. The degradation rate was found to be linear with 0.16 power of the illumination intensity. When the TC’E concentration was low (10-4mol L-1 or a little more), its degradation rate model could be considered as first order kinetics. A mechanism oi valence band hole oxidation was proposed.

The electrochemical quartz crystal microbalance (EQCM) and density functional theory (DFT) have been combined to study the special reaction between thiourea (TU) and metal cluster and the mechanism of the replacement of Cu by Sn in the presence of TU for the first time. The natural bond orbital (NBO) charge of the top copper atom obviously shifts toward positive values compared to the interaction behavior of single and double (SdC) regions with Cu4 cluster via the DFT method. This can explain the reason for the accelerating corrosion process at higher TU concentrations since the copper atoms can change to cuprous ions in this process. It is proven that the thermodynamically impossible replacement of Cu by Sn can occur in the presence of TU by reducing the OCP of the copper electrode to a more negative value than the redox potential of Sn2+/Sn. The DFT investigation on the interactions between delocalization (SdC) and (NsC) regions in TU and Cu4 or Sn4 cluster indicates that the highest molecular occupied orbital (HOMO) of the SdC region has better than adequate to the lowest unoccupied molecular orbital (LUMO) of Cu4 cluster than that of Sn4 cluster. The replacement mechanism deduced based on the first-principles analysis is universally applicable to the alloy deposition, corrosion inhibition, and surface treatment.

In this study, conventional TiO2 powder was heated in hydrogen (H2) gas at a high temperature as pretreatment. The photoactivity of the treated TiO2 samples was evaluated in the photodegradation of sulfosalicylic acid (SSA) in aqueous suspension. The experimental results demonstrated that the photodegradation rates of SSA were significantly enhanced by using the H2-treated TiO2 catalysts and an optimum temperature for the H2 treatment was found to be of 500-600℃. The in situ electron paramagnetic resonance (EPR) signal intensity of oxygen vacancies (OV) and trivalent titanium (Ti3+) associated with the photocatalytic activity was studied. The results proved the presence of OV and Ti3+ in the lattice of the H2-treated TiO2 and indicated that both were contributed to the enhancement of photocatalytic activity. Moreover, the experimental results presented that the EPR signal intensity of OV and Ti3þ in the H2-treated TiO2 samples after 10 months storage was still significant higher than that in the untreated TiO2 catalyst. The experiment also demonstrated that the significant enhancement occurred in the photodegradation of phenol using the H2-treated TiO2.