化工专业课英语.docx

1.Photocatalytic H2 production on Pt/TiO2SO42- with tuned surface-phase structures: enhancing activity and reducing CO formation Abstract:Photocatalytic reforming of biomass is a promising way to produce hydrogen using renewable energy. Photocatalytic reforming of methanol on Pt/TiO2SO42_ as a model reaction of biomass reforming was investigated. Sulfated TiO2 (TiO2SO42_) with a tunable surface phase was prepared by calcining commercially available titanium dioxide TiO2 (Degussa P25) with deposited sodium sulfate Na2SO4 as a modifier. Compared with P25, the as-prepared TiO2SO42_ with Pt co-catalyst shows an increase up to 6-fold in the activity for H2 production via photocatalytic reforming of methanol, and the CO(undesired product) concentration in the produced H2 is decreased by about two orders of magnitude.XRD patterns and UV Raman spectra clearly indicate that TiO2 depositing with Na2SO4 can significantly retard the phase transformation from anatase to rutile during calcination at elevated temperatures. It is proposed that both the phase composition and the high crystallinity of TiO2 contribute to the high H2 evolution activity. IR spectra of pyridine adsorption and the NH3-TPD profile show that the surface acid sites of the photocatalyst are greatly reduced after calcination at high temperatures. It is proposed that the decrease in the acidity of the samples might be responsible for the low CO selectivity.光催化制氢使用Pt/TiO2SO42-催化剂（可调相组成结构）：增加活性并且抑制CO的生成摘要：光催化改革生物质是制氢的有前景方法，这也是利用了可再生能源。使用硫酸化的鉑掺杂二氧化钛光催化改革甲醇是改革生物质的一个典型例子，并且研究了这种方法。通过燃烧硫酸钠共沉淀的二氧化钛利用燃烧法制备了具有可调表面相的硫酸化的二氧化钛催化剂。和P25比，在从光催化甲醇制氢上，硫酸化的二氧化钛和Pt的掺杂使制氢的活性增加了六倍，并且CO（不希望的副产物）在氢气中的浓度降低了两个数量级。XRD和紫外拉曼光谱清晰的表明硫酸钠共沉淀的二氧化钛在程序升温下可以明显的实现从锐钛矿相和金红石相之间转变。从此可以推断出相的组成和二氧化钛高的结晶度使生氢的活性增加。吡啶红外吸收光谱和氨气-TPD图谱表明了光催化剂表面的酸性在高温焙烧后大大的降低。所以可以判断表面酸性的降低可以抑制CO的产生。文献：Photocatalytic H2 production on Pt/TiO2-SO42- with tuned surface phase structures: enhancing activity and reducing CO formationYi Ma,Qian Xu,Xu Zong,Donge Wang,Guopeng Wu,Xiang Wang and Can Li*，Energy Environ.Sci.,20122 Photocatalytic activity of rutileanatase coupled TiO2 particles prepared by a dissolutionreprecipitation methodAbstract Rutile TiO2 particles were partly dissolved into aqueous solutions of H2SO4, and the Ti4+ ions were reprecipitated by adding NH3 aq. Rutileanatase coupled TiO2 particles were prepared by heating the solid recovered after centrifugation of the suspension. The content of anatase (cA, wt%) could be controlled arbitrarily by changing the dissolved amount of rutile. The photocatalytic activity for the gasphase oxidation of acetaldehyde was evaluated. The first-order rate constant, k, strongly depended on both cA and heating temperature (Tc),increasing with an increase in Tc at Tc _ 800 C. The sample with cA= 0.5 wt% prepared at Tc = 800 C exhibited a much higher level of activity (k = 0.94 h1m2) than those of pure rutile (k = 0.08 h1m2) and anatase (k = 0.34 h1m2). This remarkable enhancing effect was explained mainly in terms of photoinduced interfacial electron transfer from anatase to rutile.Keywords: TiO2; Anatase; Rutile; Semiconductor coupling; Photocatalyst用溶解再沉淀的方法制备具有光催化活性的金红石相-锐钛矿相二氧化钛粒子摘要：含金红石的二氧化钛部分溶解于硫酸水溶液中，向上面溶液中加入氨水溶液使4价的钛离子再沉淀。金红石-锐钛矿的二氧化钛粒子的制备是通过加热上面的固体，该固体是有上面的悬浊液经离心得来的。锐钛矿的质量分数可以通过溶解的金红石的量来任意的调节。实验把乙醛作为反应物来评价光催化的活性。第一反应级数速率常数k，在很大的程度上依赖于锐钛矿的浓度和加热的温度，在小于800C的范围内，随温度的增加k是增加的。制备的样品中，当锐钛矿的质量分数为0.5%，温度为800C时，和纯的金红石（k=0.08）和纯的锐钛矿（k=0.34）相比，具有较高的活性（k=0.94）.从光诱惑界面电子转移的方面来说，该活性显著的增加主要是因为锐钛矿向金红石相的转变。关键字：二氧化钛，锐钛矿，金红石，半导体结合，光催化剂文献 photocatalytic activity of rutile-anatase coupled TiO2 particles prepared by a dissolution-reprecipitation method Tetsuro Kawahara,Toshiaki Ozawa, Mitsunobu Iwasaki,Hiroaki Tada, and Seishiro Ito ,Journal of Colloid and Interface Science 267 (2003) 3773813 Enhancing hydrogen production activity and suppressing CO formation from photocatalytic biomass reforming on Pt/TiO2 by optimizing anataserutile phase structureAbstract:The photocatalytic activity in hydrogen production from biomass reforming can be significantly enhanced while keeping ultra-low CO concentration in produced H2 by tuning the anataserutile phase structures of Pt/TiO2 photocatalysts. Compared with Pt/P25, the overall photocatalytic activity for the photocatalyst with optimized anataserutile structure can be enhanced up to 35 times, and the CO concentration in hydrogen can be reduced from several thousands ppm to 5 ppm. It is proposed that the anataserutile phase structure can not only enhance the charge separation, consequently the activity, but also adjust the surface acid/base property which suppresses the CO formation.优化的锐钛矿-金红石相结构Pt-TiO2光催化剂重整生物质制氢:增加生氢的活性和抑制CO的生成摘要：从生物质重整中光催化制氢，使用可调锐钛矿-金红石相组成的光催化剂Pt-TiO2可以在氢气生成的过程中保持CO量极少。和Pt/P25相比，可调锐钛矿-金红石相组成的光催化剂可以使总的光催化活性提高3-5倍，并且在H2中的CO的含量可以从几千个ppm降低到5个ppm。可以推断出，锐钛矿-金红石相的结构不仅增加电荷的分离，不断的提高活性，而且可以调节表面的酸碱度的比值，这一比值的大少可以抑制到CO的生成。文献：. Enhancing hydrogen production activity and suppressing CO formation from photocatalytic biomass reforming on Pt/TiO2 by optimizing anatase-rutile phase structure，Qian Xu, Yi Ma, Jing Zhang, Xiuli Wang, Zhaochi Feng and Can Li*， J. Catal, 2011, 278, 329-335,4 Size-Controlled Synthesis of Spherical TiO2 Nanoparticles: Morphology, Crystallization,and Phase TransitionAbstract :Obtaining spherical-shaped semiconductor nanoparticles of uniform size is essential for the fabrication ofphotonic crystals. We report the synthesis of nanometer-size spherical titania particles with narrow sizedistribution from glycolated precursors. Through controlled hydrolysis of glycolated precursors, particles of683 to 50 nm average diameters, with narrow size distribution, could be produced for the first time. Effectsof air annealing on the morphology, size shrinkage, and phase transition of the nanoparticles are studied byscanning electron microscopy, X-ray diffraction, Raman spectroscopy, and high-resolution electron microscopytechniques. Probable mechanisms for formation of titania nanoparticles and their size control are discussed.球形二氧化钛纳米粒子可控尺寸的合成：形态学、结晶化和相转变摘要：获得尺寸一致的球形半导体纳米粒子对光子晶体的合成是必要的。我们报道一种球形二氧化钛纳米粒子的合成方法，它是以乙醇酸酯为前体，并且是以很少的尺度分布的。通过控制乙醇酸酯前体的水解作用，粒子的平均半径可以再50到683nm，并且这种分布是很窄的，而且可以一次合成。形态学上的空气退火，尺寸的缩小以及相的转变，粒子的上述这些影响可以通过SEM,XRD,Raman，和HRTEM来研究。我们讨论了生成二氧化钛纳米粒子的几种可能的机理和尺寸的控制的方法。文献：Size-Controlled Synthesis of Spherical TiO2 Nanoparticles: Morphology, Crystallization,and Phase Transition，Mou Pal, J. Garca Serrano, P. Santiago, and U. Pal, J. Phys. Chem. C 2007, 111, 96-102，5. Photoluminescence Characteristics of TiO2 and Their Relationship to the Photoassisted Reaction of Water/Methanol MixtureAbstract :This work investigated the photoluminescence characteristics of TiO2 and discussed the relationship between the photoluminescence features of TiO2 and the photoassisted reaction of water/methanol mixture. It is found that anatase TiO2 disp lays a visible luminescence band centered at about 505 nm and rutile TiO2 mainly shows a near-infrared luminescence band centered at about 835 nm, which are respectively ascribed to the oxygen vacancies in anatase TiO2 and the intrinsic defects in rutile TiO2. The visible luminescence band is easily quenched by the Pt deposited on the surface of TiO2, while the near-infrared luminescence band is hardly influenced by the deposited Pt. It is suggested that the excited electrons trapped in the oxygen vacancies of anatase are facilely transfe