查询词典 photocatalytic

Result of photocatalytic degradation of methyl orange showed that the TiO2 photocatalytic activity decreased with the decreasing of anatase ratio in the mixed crystallite of anatase,rutile,and brookite;and photocatalytic activity of pure rutile TiO2 was relatively bad.

光催化降解甲基橙的研究表明，所得锐钛矿、金红石和板钛矿3种混晶中，二氧化钛的光催化活性随着锐钛矿含量的降低而降低；纯金红石型二氧化钛的光催化活性较差。

But, because of the complexity of the dye molecule, there has been short of detailed comprehension in its photocatalytic degradation process. The key problem is difficult to detect the intermediates clearly. In this paper, the photocatalytic degradation of azo dye Congo red in water solution was investigated on UV irradiating TiO2 in the homemade reactor. The optimization conditions were determined and then the rate of decolorization, COD decrease, yield of CO2 and varies pH of aqueous solution during illumination were detected; The varies of the possible intermediates during degradation process were monitored with UV-VIS spectrum and HPLC. The possible mechanism of Congo red photocatalytic degradation is discussed combined with the data of MS.

本文选择有代表性的常见偶氮染料—刚果红作为研究对象，以自制TiO2为催化剂和小功率紫外灯为光源，在自制光反应器上确定了光催化降解的优化条件，并在这个优化条件下测定了降解过程中的脱色率、COD去除率和CO2生成量；利用数显酸度计、紫外可见分光光度计和高效液相色谱仪跟踪测定了降解过程中的可能产物，并结合质谱的数据初步探讨了刚果红的可能降解机制。

Selective doping has been proved to be a semiconductor oxide improve the photocatalytic activity of the most effective ways The introduction of certain metal ions can greatly improve the photocatalytic oxidation efficiency, Recently, a lot on the adoption of the doping to improve the photocatalytic oxidation performance reports, doped semiconductor photocatalysis material because of its physical and optical properties change, thereby improving the photocatalytic properties.

有选择性的进行掺杂已被证明是一种提高半导体氧化物光催化活性的极其有效的方法，掺入一定的金属阳离子能极大的提高TiO2的光催化效率，最近有大量的关于通过掺杂来提高TiO2的光催化性能的报道，掺杂的半导体光催化材料由于其物理和光学性质的改变，通过扩展光响应范围和提高光生电荷的分，从而提高了光催化性能。

And photocatalytic activity of the thin films were evaluated by photocatalytic decoloration of methyl orange aqueous solution. The following results and conclusions are obtained. The photocatalytic activity of TiO2 thin films on soda lime glass is lower than that of TiO2 films on pre-coated with SiO2 coating.

研究结果表明：在热处理过程中钠钙离子容易从玻璃基体扩散到TiO2薄膜内，在TiO2颗粒表面和本体形成光生电子和空穴的复合中心，同时抑制具有光催化活性的锐钛矿相TiO2的形成。

However, it has found that sodium ions in TiO2 thin film diffused from the glass substrate during heat treatment have deleterious effects on the photocatalytic activity of TiO2- To develop new ecotypic building and environmental harmony materials and extend the use of the photocatalytic TiO2 thin films in the field of building materials, this thesis presents the preparation and the enhancement methods for the photocatalytic of TiO2 thin film on the surface of soda lime glass.

为发展新的生态建筑材料和环境协调材料，拓展二氧化钛在建筑材料领域的应用，该论文研究了普通玻璃表面TiO_2纳米薄膜的溶胶-凝胶工艺制备和光催化活性的增强方法。

The results showed that the application of photocatalytic oxidation to the treatment of wastewater was feasible and efficient, but it was affected by the operation conditions.There existed optimum value of the dosage of catalyst, initial benzamide concentration and pH value for the photocatalytic oxidation performance.H2PO-4,Cl-, Cu2+ and Al3+ showed obvious inhibition to the photocatalytic oxidation.

结果表明，循环式浆态光催化反应器中光催化剂的用量、污染物的初始浓度和初始pH值对模拟污染物光催化降解性能的影响存在适宜值；体系中H2PO-4、Cl-、Cu2+、Al3+对其光催化降解过程有明显的抑制作用。

SO〓〓/M〓O〓 solid superacid was applied to the photocatalytic oxidation of organic pollutants for the first time. Porous SO〓〓/TiO〓 solid superacid catalysts with high specific surface area were prepared by sol-gel method. The photocatalytic degradation of bromomethane was used as model reaction. The influence of impregnation with H〓SO〓 solution on the structure of catalysts and their photocatalytic performance was systematically studied by using X-ray diffraction, X-ray photoelectron spectroscopy, N〓 sorption analysis applying BET method, UV-Vis diffuse reflectance spectroscopy, FTIR spectroscopy, O〓-TPD and photocatalytic activity measurement. The acidity of TiO〓-based catalysts was investigated by Hammett indicator method, NH〓-TPD and IR spectra of pyridine adsorbtion. The mechanism of superacidifing effects on photocatalytic performances such as the photocatalytic degradation rate of bromomethane, apparent kinetic constant and apparent quantum efficiency was discussed.The results indicated that SO〓〓 is combined with metal ions of TiO〓 in a chelating bidentate mode.

本文首次将SO〓〓/MxOy型固体超强酸催化剂用于光催化氧化有机污染物研究，采用溶胶-凝胶法制备了具有多孔性和大比表面结构的二氧化钛基固体超强酸光催化剂SO〓〓/TiO〓，以光催化降解溴代甲烷为模型反应，系统地研究了H〓SO〓浸渍处理对催化剂表面酸性及其气相光催化性能的影响，结合XRD、BET、XPS、FTIR、Hammett指示剂法、吡啶吸附红外光谱、NH〓-TPD、O〓-TPD、紫外可见漫反射光谱等多种表征手段，深入地讨论了超强酸化对TiO〓的改性机理，阐明了引起SO〓〓/TiO〓超强酸催化剂光催化降解溴代甲烷的转化率、表观反应速率常数和表观量子效率变化的本质原因。

The structural and photocatalytic properties of TiO〓 as well as surface acidity were greatly improved by sulfation. SO〓〓/TiO〓 solid superacid with Hammett constant Ho less than -12.14 was prepared by treating the TiO〓 with 1.0mol. L〓 sulfuric acid solution and then calcining at 450℃ for 3h. When compared to unmodified TiO〓, the SO〓〓/TiO〓 superacid catalyst exhibited higher anatase content, smaller crystal size, higher specific surface area, centralized pore size distribution, and the blue-shifted band edge of uv-vis adsorption spectra. Furthermore, the SO〓〓/TiO〓 superacid also showed excellent reaction activity and stability for CH〓Br photocatalytic decomposition even under the moist reaction conditions. The apparent quantum efficiency of SO〓〓/TiO〓 was 10 times of that of TiO〓 catalyst for the photocatalytic degradation of bromomethane. Therefore, the SO〓〓/TiO〓 superacid catalyst is promising for practical application in environmental remediation.It was found that both L and B acid sites exist on SO〓〓/TiO〓 photocatalyst while only L acid sites on TiO〓 photocatalyst. On the basis of experimental results, the synergistic model of superacidic centers was proposed for SO〓〓/TiO〓 photocatalyst to explain the photocatalytic behavior and the mechanism of superacidifing effects, assuming that the adjacent L and B acid sites induced by SO〓〓 comprise cooperatively the superacidic center on superacid photocatalyst. The group cooperation of the superacidic center could strengthen the surface acidity, increase surface acid sites and the adsorbtion of O〓, promote separation of photogenerated electron-hole pair, enhance the interfacial transfer of charges and reversibility of water adsorption. Consequently the excellent photocatalytic activity, reaction stability and resistibility to humidity of SO〓〓/TiO〓 superacid photocatalyst may attributed to the group cooperated effect of the superacidic center on the photocatalyst.

研究结果表明：SO〓〓与TiO〓表面的结合为螯合式双配位结构；TiO〓光催化剂表面经H〓SO〓浸渍处理后，提高了表面酸性，改善了催化剂结构和光催化性能，当H〓SO〓浸渍浓度为1.0mol.L〓、烧结温度为450℃时，可制得SO〓〓/TiO〓超强酸催化剂(H〓＜-12.14)，其结构和光催化活性得到明显改善，与TiO〓相比，SO〓〓/TiO〓光催化剂的锐钛矿含量高、晶粒小、BET比表面积大、孔径分布集中、光谱吸收边蓝移，具有优异的光催化氧化活性、稳定性及抗湿性能，光催化降解溴代甲烷的表观量子效率比TiO〓催化剂提高了一个数量级，是一种有实际应用前景的高效光催化剂；由此提出了SO〓〓/TiO〓超强酸催化剂表面集团协同作用的超强酸中心模型，认为在SO〓〓/TiO〓超强酸催化剂表面，由SO〓〓诱导的相邻L酸中心和B酸中心组成了集团协同作用的超强酸中心，其集团协同作用显著地增强了催化剂表面酸性、增大了表面酸量及O〓吸附量、促进了光生电子和空穴的分离及界面电荷转移，具有可逆吸附水的性能，是SO〓〓/TiO〓超强酸催化剂具有优异的光催化氧化活性、很好的活性稳定性及抗湿性能的重要原因。

The results showed that (1) The grain size of nanometer YiO_2 was40～80nm.The wavelength corresponding to the maximum absorbency values were observedin the 200～320nm range.The crystal structure of carbon doped TiO_2 photocatalyst is primarilyanatase(22.43% rutile), and the content of carbon is about 4.6%.(2) The relative humidityvaring from 8% to 80%, the photocatalytic degradation degree of benzene increased withincreasing relative humidity; and to toluene, degradation rate was hanced by relative humidityup to 60%, and more or less inhibited above 60%.(3) Scheme and results of orthogonal testswere used by evaluating the photocatalytic performance of the gas phase methanol, acetoneand 1-heptane.The results revealed that their degradation degree reached 84.5%, 93.39% and93.45%, respectively.(4) The 254nm UV lamp showed higher photocatalytic degradation rate.For methanol, acetone and 1-heptane, it was found that photocatalytic degradation reactionoccurs with the light strength of daylight lamp.(5) Under the the same conditions, 15%degradation degree has been obtained for benzene, whilst about 10% degradation degree wasattained by Degussa P25; During the initial phases, the toluene revealed higher photocatalyticactivity, comparing with Degussa P25, the degradation degree of methanol, acetone and1-heptane were slightly lower.

结果表明：(1)CVD法制备的纳米TiO_2光催化剂，颗粒球形度好、粒径在40～80nm之间；最大吸光度值所对应的波长为200～320nm；含碳量约为4.6％；晶型组成主要为锐钛矿型，金红石的含量约为22.43％；(2)在相对湿度为8％～80％范围内，苯的光催化降解率随着相对湿度的增大而增大；甲苯在相对湿度为60％时达到最好降解效果，当相对湿度增大到80％时光催化效果降低；(3)将正交实验设计及实验方案应用于气相甲醇、丙酮和正庚烷光催化降解研究，实验结果表明：三者最高降解率分别为84.5％、93.39％和93.45％；(4)有254nm紫外灯参与的光催化实验可以大大提高有机气体的光催化降解率；在日光灯的照射下，掺碳纳米TiO_2对气相甲醇、丙酮和正庚烷具有一定的光催化氧化能力；(5)较P25粉，在相同的光催化操作条件下：气相苯的平均降解率达15％，高于P25粉10％的降解率；气相甲苯在初始阶段具有较高的反应速率；气相甲醇、丙酮和正庚烷的降解率略低于P25粉。

The following main results are obtained: The TiO_2 photocatalyst with small crystallite size, high surface area, narrow and uniform pore size distribution, and microporous frameworks could be prepared out by applying MW radiation in the preparation process. The microwave-induced fluorescence technique verified for the first time that microwave enhanced the formation rate of hydroxyl radical, leading to the increase in the photocatalytic efficiency. Compared with the conventional catalyst, TiO_2 prepared by MW dielectric heating owns a higher UV absorption ability, and its optical absorption edge and photovoltaic response are shifted toward the short wavelength region, resulting in increase of photooxidation efficiency. The photocatalytic conversion and the mineralization ratio of acetaldehyde are increased respectively by 30% and 40% over the TiO2 prepared by MW radiation when compared to the TiO2 prepared by the conventional heating. For the MW-assisted photocatalytic reaction over the MW-prepared TiO2, production of hydroxyl radicals is enhanced by 22.5%, and the photocatalytic conversion is accordingly increased by 20%. Similarlly, applying MW also increased the photocatalytic conversion and the mineralization ratio of acetaldehyde over TiO2/Al2O3 sample.

论文得到如下主要结果和结论：(1)微波介电加热TiO_2 溶胶可得到晶粒度小、光催化活性高、比表面积大和孔径分布窄而均一，且微孔发达的TiO_2光催化剂；在溶胶干燥处理过程中微波可使催化剂表面缺陷增加，进而导致光催化反应过程有更多的活性羟基自由基产生；(2)微波制备能显著增强TiO_2 样品的紫外光吸收率，并使其光吸收和光伏响应阈值发生蓝移，从而提高TiO_2的氧化还原能力；(3)与常规加热法所制TiO_2比较，微波法制备的TiO_2对乙醛的光催化降解转化率提高30%，CO_2生成率提高40%以上；(4)与未加微波辐射时相比，发现在光催化反应过程中施加微波，TiO_2 的羟基自由基生成速率提高了22.5%，相应CH_3CHO 光催化降解转化率提高了20%；对Al_2O_3/TiO_2催化剂，CH_3CHO 光催化降解转化率甚至提高了33%，同时CO_2 的生成率也都大幅度提高；(5)微波辐射可改变光催化降解乙醛的产物分布，推断施加微波时乙醛光催化降解按照羟基自由基引发的链式反应机理进行，微波&非热效应&起主要作用。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。