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81.
Jiemei Yu Zongming Liu Haitao Zhang Taizhong Huang Jitian Han Yihe Zhang Daohuang Chong 《环境科学学报(英文版)》2015
Three types of TiO2 nanostructures were synthesized via a facile hydrolysis method at 195 °C. Effects of the preparation method and doping with N and F on the crystal structure and photocatalytic performance of TiO2 were investigated. The nanomaterials were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller porosimetry, ultraviolet–visible diffuse reflectance spectroscopy and fluorescent emission spectra. Their photo-catalytic activity was examined by the photodegradation of methylene blue in aqueous solution under both ultra-violet and visible light irradiation. The results show that nitrogen and fluorine co-doped anatase TiO2 had the characteristics of a smaller crystalline size, broader light absorption spectrum and lower charge recombination than pure TiO2. Most importantly, more efficient photocatalytic activity under both ultra-violet and visible light was observed. The obtained N–F-TiO2 nanomaterial shows considerable potential for water treatment under sunlight irradiation. 相似文献
82.
本研究结合阳极氧化和超声辅助沉积的方法合成碳氮共掺杂的二氧化钛纳米管阵列,并采用XRD、FESEM、UV-vis、XPS等技术对材料进行表征.光电化学(PEC)体系中,碳氮共掺杂二氧化钛纳米管阵列作为阳极,甲基橙溶液作为光电催化氧化的对象,对光催化剂的氧化性能进行了考察,与此同时,在阴极实现光解水产氢,最终在PEC体系中实现同时降解甲基橙和产氢.XRD、FESEM、UV-vis、XPS及TEM等表征结果表明,碳氮成功地掺入到了二氧化钛纳米管阵列中,并未破坏其多孔有序的结构,而且比二氧化钛纳米管阵列具有更高的光催化活性.光电催化降解甲基橙的实验当中,在酸性溶液条件下,二氧化钛纳米管阵列的催化氧化效率较高,降解效率达到了100%,其速率常数为2.3×10-3s-1(p H=4),同时也具有较高的产氢速率(0.95 mmol·h-1),因此,该实验体系在光电催化降解污水中的有机污染物同时产氢方面有应用前景. 相似文献
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采用熔盐法制备了能级位置可控的钾离子掺杂石墨相氮化碳催化剂(g-C3N4),并考察了其在可见光下降解罗丹明B(RhB)性能.采用XRD、UV-Vis、XPS、N2吸附、PL、EIS等手段对催化剂进行了表征.结果表明,钾离子的引入降低了催化剂粒径尺寸,提高了比表面积,改善了光生电子-空穴对的分离效率.不仅如此,通过控制钾离子掺杂量可以实现催化剂的能级位置在一定范围内的任意调变,使有机污染物的氧化降解反应从·O2-单一氧化剂反应变成·OH和·O2-双氧化剂反应,大大提高了降解率.制备的钾离子掺杂g-C3N4的RhB降解速率常数达到0.022min-1,是纯g-C3N4的5倍.不仅如此,通过对能级位置的调控,制备的催化剂对其他多种有机污染物如甲基蓝,苯酚等的降解率也有显著提高. 相似文献
84.
采用实验室合成的Sb2O5掺杂TiO2作为催化剂,研究各种因素对甲基橙的超声催化降解反应的影响.结果表明,在Sb2O5掺杂TiO2催化剂作用下,甲基橙的超声催化降解效果明显优于单独使用TiO2的情况.1.5%掺杂量的催化剂,用量在1.0~1.5 g/L之间,超声波频率25 kHz,输出功率1.0 W/cm2,pH为1.0~3.0时,初始浓度为20 mg/L的甲基橙水溶液,100 min左右基本可全部降解,COD去除率达到99.0%以上.Sb2O5掺杂TiO2催化超声降解有机污染物的方法具有很好的应用前景. 相似文献
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通过空穴和自由基捕获剂的加入,首先研究了可见光激发下手性TiO2复合光催化剂降解罗丹明B和四环素的机理. 结果表明,可见光激发TiO2光催化剂降解罗丹明B和四环素的机理是相同的,其形成的光生空穴是降解有机物的关键影响因素.利用D型手性表面活性剂在低温时可以构建右旋非对称手性堆积结构的D-TiO2. 这种非对称结构在介孔TiO2内部引入氧空穴和Ti-N键,使D-TiO2也具有显著的可见光响应和可见光降解活性. La3+ 或者Fe3+的掺杂几乎不影响催化剂的形貌及其TiO2的结晶过程, 但可以在催化剂中形成光生空穴和电子的捕获中心,显著提升可见光激发下TiO2催化剂中光生空穴和电子的分离率,从而增强催化剂对四环素的光降解活性. 相似文献
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采用密度泛函理论研究了γ-Fe2O3表面As2O3的吸附以及掺杂改性提高抗As2O3中毒性能的作用机理.计算了As2O3在完整以及O缺陷γ-Fe2O3(001)表面的吸附性能,包括吸附位点、吸附结构、吸附能、PDOS等.同时建立了Mo、Ti、Mg掺杂的γ-Fe2O3模型,探讨了助剂掺杂对抗砷中毒能力的作用机制,并考虑了掺杂量的影响.结果表明:As2O3倾向于以O端化学吸附在γ-Fe2O3(001)表面Feoct位,吸附过程发生强烈的相互作用和电荷转移.当表面存在O缺陷时,As2O3的吸附能得到提高.Mo、Ti、Mg倾向于掺杂在Feoct位,增强了对As2O3的吸附能力,并且增大Mo的掺杂量可以强化As2O3的吸附.As2O3倾向于与活性较强的Mo、Ti、Mg发生反应,从而保护活性Fe位不受砷中毒,Ti和Mg的掺杂还抑制了相邻Fe位对As2O3的吸附.Mo、Ti、Mg的掺杂还促进了催化剂表面对NH3的吸附,增强了表面酸性强度,有利于SCR反应.Mo、Ti、Mg原子的掺杂有利于提高γ-Fe2O3催化剂的抗砷中毒性能. 相似文献
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通过简单的水热及煅烧方法制备了脯氨酸掺杂的g-C3N4纳米片,借助FTIR、XRD、SEM、BET、XPS、UV-vis DRS、PL、电化学工作站等手段对所制备的光催化剂进行结构、形貌、组成及光电性能表征分析.结果表明,脯氨酸的加入可以自主剥离前驱体,制成纳米片状的g-C3N4,增加催化剂的比表面积.此外脯氨酸的引入可以调节催化剂的能带结构,增加可见光吸收,提高光生载流子分离率.在模拟可见光照射下,考察其对罗丹明B (RhB)的光催化降解性能获得了最优掺杂条件.1%脯氨酸掺杂(PCN-1%)的催化剂经过60min可见光照射即可降解99%以上的污染物.降解速率得到显著提升,PCN-1%对RhB的降解速度(0.0271min-1)达到传统体相氮化碳(BCN)降解速率(0.0027min-1)的10.04倍,显著提高了g-C3N4的光催化能力. 相似文献
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Enhui Wu Daifeng Lin Yinye Chen Xiaoshan Feng Kui Niu Yongjin Luo Baoquan Huang Jianbin Qiu Qingrong Qian Qinghua Chen 《环境科学学报(英文版)》2022,34(6):79-89
A series of nitrogen-doped CoAlO (N-CoAlO) were constructed by a hydrothermal route combined with a controllable NH3 treatment strategy. The effects of NH3 treatment on the physico-chemical properties and oxidation activities of N-CoAlO catalysts were investigated. In comparison to CoAlO, a smallest content decrease in surface Co3+ (serving as active sites) while a largest increased amount of surface Co2+ (contributing to oxygen species) are obtained over N-CoAlO/4h among the N-CoAlO catalysts. Meanwhile, a maximum N doping is found over N-CoAlO/4h. As a result, N-CoAlO/4h (under NH3 treatment at 400°C for 4 hr) with rich oxygen vacancies shows optimal catalytic activity, with a T90 (the temperature required to reach a 90% conversion of propane) at 266°C. The more oxygen vacancies are caused by the co-operative effects of N doping and suitable reduction of Co3+ for N-CoAlO/4h, leading to an enhanced oxygen mobility, which in turn promotes C3H8 total oxidation activity dominated by Langmuir-Hinshelwood mechanism. Moreover, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) analysis shows that N doping facilities the decomposition of intermediate species (propylene and formate) into CO2 over the catalyst surface of N-CoAlO/4h more easily. Our reported design in this work will provide a promising way to develop abundant oxygen vacancies of Co-based catalysts derived from hydrotalcites by a simple NH3 treatment. 相似文献