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.

A three-electrode system composed of TiO2/Ni as the working electrode, porous nickel as the counter electrode, and saturated calomel electrode (SCE) as the reference electrode was used for the photoelectrocatalytic degradation of organic compounds. The photoelectrocatalytic degradation of sulfosalicylic acid (SSal) under anodic bias potential was investigated. It is shown that SSal can be degraded effectively as the external potential is increased up to 700 mV (vs SCE). The characteristics by electrochemical impedance spectroscopy (EIS) of the photoelectrocatalytic degradation of sulfosalicylic acid (SSal) was also investigated. It is shown from the EIS that the photoelectrocatalytic degradation appears to be a simple reaction on the electrode surface, suggesting that only one step of charge transfer is involved in the electrode process. The value of the resistance of charge transfer for the photoelectrocatalytic reaction of SSal manifests itself not only in the reaction rate, but also in the separation efficiency of the photogenerated electron-hole pairs. The separation efficiency of the electron-hole pairs under N2 atmosphere is higher than that under O2 atmosphere.

以二氧化钛为光催化剂，主波长254nm紫外线杀菌灯为光源，研究了气相三氯乙烯（TCE）在无水条件下的光催化降解反应。结果发现，TCE的光催化降解产物为HCl、CO2及Cl2，并得出TCE在无水条件下光催化反应的计量式为C2HCl3+2O2hv/TiO2HCl+2CO2+Cl2，该计量式与有水条件下光催化反应降解TCE的计量式不同。结果还发现，TCE初始反应速率与光强的0.16次方呈正比，光催化降解速率方程符合Langmuir-Hinshelwood公式〔1〕。

研究了由偏钛酸在不同温度下焙烧制成的TiO2，经氢还原后用于光催化降解磺基水杨酸（SSal）以及TiO2的漫反射光谱和荧光光谱特征结果表明，锐钛型TiO2在经550℃氢还原处理120min后，光催化活性明显提高；600℃条件下焙烧制得的TiO2，经氢还原后其光催化降解SSal的反应活性最高漫反射光谱结果表明，800℃条件下焙烧制得的TiO2，开始出现转晶现象，从锐钛型逐渐向金红石型过渡TiO2荧光光谱的荧光峰面积（F）和倍频峰面积（R）的比值越大，TiO2光催化降解SSal的活性越高，提出了氢还原后TiO2的光催化作用机制。

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.