偶氮染料刚果红在水中的光催化降解过程

通过研究在间歇悬浮体系中直接偶氮染料刚果红在水中的光催化降解过程 ,确定了最佳降解条件 .同时测定了染料溶液的脱色率、COD去除率和矿化率以考察降解过程中脱色与矿化的关系 .另外 ,对降解过程中溶液 pH值的变化及反应的可能中间体进行分析 ,结果表明 :刚果红染料分子的光催化降解过程分为脱色和矿化两个阶段 .矿化主要发生在脱色结束以后 ,并且伴随着脱色溶液的酸化现象 .脱色过程进行较快 ,完全脱色后形成的中间产物需要较长时间才能被逐步矿化 .

TiO_(2)/MoS_(2)材料的制备及其催化降解甲基橙的研究

以钛酸丁酯为钛源,MoS_(2)为负载剂,通过溶胶-凝胶法和水热法制备TiO_(2)/MoS_(2)复合光催化剂。通过FT-IR、XRD、DRS、SEM、ERS和N_(2)吸附-脱附等对催化剂组成、形貌及结构进行分析,并且以降解率为评价指标通过光催化甲基橙有机污染物来评价其催化活性。对负载量、复合催化剂用量和pH等进行优化研究。研究发现,TiO_(2)/MoS_(2)复合催化剂稳定性高、催化活性强。0.50 g TiO_(2)/MoS_(2)复合催化剂常温矿化降解50 mL的5 mg·L^(-1)甲基橙溶液的降解率达97.53%。此外,复合材料催化降解甲基橙溶液这一过程符合一级反应动力学L-H方程。

Ultrafine metal nanoparticles loaded on TiO_2 nanorods:Synthesis strategy and photocatalytic activity

Ultrafine noble metal nanoparticles （Pt, Pd, or Au） co-catalyst loaded on the surface of rutile and brookite TiO2 were prepared via a simple photo-deposition strategy under high vacuum conditions. The properties of the prepared samples were determined by different characterization techniques, including X-ray diffraction, transmission electron microscopy, diffuse reflectance ultraviolet-visible spectroscopy, and photoluminescence spectroscopy. The photocatalytic performance of the samples was evaluated by monitoring the reforming of methanol. Co-catalyst loading greatly improved the photocatalytic activity of TiO2. Specifically, Pt-TiO2 displayed the highest photocatalytic activity among all samples studied, followed by Pd-TiO2 and then Au-TiO2. Furthermore, this photocatalytic behavior was not influenced by the intrinsic nature of the TiO2 semiconductor photocatalyst. Similar photocatalytic activity trends were achieved with both sets of noble metal-loaded photocatalysts prepared using rutile and brookite TiO2 as supports. By examining the physicochemical and photocatalytic properties, the factors controlling the photocatalytic activity of the noble metal-loaded TiO2 samples were discussed in detail.

Microwave-assisted ionothermal synthesis of hierarchical microcube-like BiOBr with enhanced photocatalytic activity

Bismuth oxybromide（BiOBr） with a hierarchical microcube morphology was successfully synthesized via microwave-assisted ionothermal self-assembly method. The as-obtained BiOBr was composed of regular multi-layered nanosheets, which were formed by selective adsorption of ionic liquids on the Br-terminated surface, followed by the formation of hydrogen bond-co-π-π stacking.The synthesized BiOBr exhibited high activity, excellent stability, and superior mineralization ability in the photocatalytic degradation of organic dyes under visible light owing to its enhanced light absorbance and narrow bandgap. Furthermore, photo-generated electrons were determined to be the main active species by comparison with different trapping agents used in the photocatalytic reactions.

Three-dimensionally ordered macroporous perovskite materials for environmental applications

Three-dimensionally ordered macroporous(3DOM)perovskite materials have attracted the interest from researchers worldwide due to their unique macroporous structure,flexible composition,tailorable physicochemical property,high stability and biocompatibility.In particular,they were widely used in environmental field,such as photocatalysis,catalytic combustion,catalytic oxidation and sensors.In this review,the recent progresses in the synthesis of 3DOM perovskite materials and their environmental applications are summarized.The advantages and the promoting mechanisms of 3DOM perovskite materials for different applications are discussed in detail.Subsequently,the challenges and perspectives on the topic are proposed.

Kinetics and mechanism of thymine degradation by TiO_2 photocatalysis

The advanced oxidation processes were examined toward the degradation of thymine （CsH6N202）, a type of nucleic acid from the pyrimidine family. As observed, the photodegradation of thymine over TiO2 photocatalyst was rapid and significant in aqueous solution under UV irradiation. Different parameters were studied, including the adsorption of thymine onto TiO2 photocatalyst, the kinetics of degradation, and the effect of pH on the photocatalytic properties of thymine degradation. Additionally, the mineralization of the products obtained upon thymine photodegradation was studied. The disappearance and mineralization rates of thymine during the photocatalytic process were also compared and discussed. The mineralization of nitrogen was also investigated, and the identification of the intermediate products was established. Finally, electronic density calculations were used to propose possible chemical pathways for the photodegradation of thymine over TiO2 photocatalyst under UV irradiation.

Photocatalytic activity of bauxite-tailings supported nano-TiO_2

TiO2/bauxite-tailings （TiO2/BTs） composites were prepared via a chemical liquid deposition method and characterized by X-ray diffractometry （XRD）, scanning electronic microscopy （SEM） and N2 adsorption analysis. The photocatalytic performance of TiO2/BTs composites was evaluated with UV-Vis spectrophotometer following the changes of phenol concentration under different illumination time. Effects of the calcination temperature, the pH and the cycles on the photocatalytic activity of TiO2/BTs composites were investigated. The composites calcined at 500 and 600 ℃ exhibit the best photocatalytic performance, and the phenol degradation ratios reacting for 40 and 160 rain reach 35% and 78% respectively under the same conditions, higher than those of 29% and 76% of the Degussa P25（TiO2）. The ability of TiO2/BTs500 （BTs500 represents bauxite-tailings calcined at 500 ℃） composites to degrade phenol increases with decreasing pH.