钒酸铋颜料的制备研究

本文阐述了钒酸铋颜料的基本原理与制备方法，列出了颜料性能检测结果，并讨论了温度，pH值对产品性能的影响。     

钒酸铋可见光催化剂的研究进展

BiVO_4作为一种非TiO_2基的半导体光催化剂,其禁带宽度较窄,为2.4 eV(单斜相),能在可见光区响应,因而受到了广泛的关注。到目前为止大部分的光催化剂只能在紫外光区域发挥作用,因此很有必要去开发在可见光区域发挥作用的新型光催化剂,以便于更好的利用太阳能资源。本文综述了一种新型非TiO_2基可见光照射下具有高效催化活性的光催化剂——BiVO_4,包括BiVO_4的可控合成和光催化活性以及提高BiVO_4光催化性能的主要方法。     

固相煅烧法制备钒酸铋颜料工艺研究

通过固相煅烧法制备钒酸铋颜料,研究反应原料、煅烧温度及煅烧时间对产品物相、粒度及比表面积、颜料呈色性能等的影响。结果表明:以NH4VO3及Bi(NO3)3·5H2O为反应原料,制备条件更温和;煅烧温度为500℃、煅烧时间为12 h,制备出的钒酸铋产品物相纯度较高、平均粒径及比表面积处于较优水平,产品对应的色坐标为L*=84.91,a*=1.18,b*=85.87,c*=85.88,颜料呈色性能优于市售钒酸铋颜料。     

石墨烯/半导体复合光催化剂的研究进展

较为系统地介绍了近年来利用石墨烯与半导体复合制备新型复合光催化剂的研究状况,综述了具有纳米结构的钛基、钨基、锌基、铋基等复合光催化剂的研究新进展。提出和分析了石墨烯/半导体复合光催化剂促进光催化机理,认为石墨烯能有效地提高光生电子-空穴对的分离效率,改善催化剂的物理结构和光吸收性能,从而提高光催化活性,最后提出了该领域今后发展和研究的方向。     

复合添加碳化钒石墨烯对数控机床刀具钢性能的影响

在数控机床刀具用W18Cr4V钢中添加不同含量的碳化钒和石墨烯,并进行耐磨损性能和热疲劳性能的测试与分析。结果表明,与单一添加相比,复合添加碳化钒和石墨烯对W18Cr4V钢耐磨损性能和热疲劳性能的改善效果更加显著。复合添加1.5%碳化钒和1.5%石墨烯使W18Cr4V钢的磨损体积减小81%,热疲劳裂纹级别从9级变为2级。     

溶液燃烧合成法制备钒酸锂及其电化学性能

以硝酸铵、偏钒酸铵、硝酸锂、葡萄糖、柠檬酸、甘氨酸为原料,采用溶液燃烧合成法成功制备了锂离子电池正极材料LiVO₃粉末,探究了煅烧温度和煅烧时间对LiVO₃制备的影响,并将制备得到的LiVO₃粉末作为活性物质进行电池组装,进一步探究了其作为锂离子电池正极材料时的电化学性能。结果表明：400℃煅烧1 h时制备的LiVO₃粉末具有最佳的电化学性能,0.1 A/g的充放电速率下,电池首次放电比容量为244.3 mAh/g,经过50次循环后放电比容量为193.6 mAh/g。     

纳米Ce/TiO2光催化剂的制备及光催化性能

以TiCl4为原料,Ce(NO3)2·6H2O为掺杂剂,制备了铈掺杂TiO2纳米粒子并进行了X射线衍射表征和气相光催化性能评价。实验结果表明,铈掺杂对样品的光催化活性有影响,随着掺铈量的增加样品的光催化活性提高。掺铈量大于4%以后活性变化不再明显。样品的焙烧温度和时间也对样品的光催化活性有影响。此外,样品的粒径随制备中的pH值降低而减小。     

还原石墨烯改性二氧化钛/壳聚糖多孔复合材料的光催化性能

采用冷冻浇注法制备TiO_2/壳聚糖多孔复合材料,研究二氧化钛含量对该复合材料的微观结构、抗压强度及光催化性能的影响。结果表明:TiO_2/壳聚糖多孔复合材料具有明显的长程有序结构,片层状排列的平行度良好。随TiO_2含量(质量分数,下同)从66.7%增加到88.8%,片层中的孔间距从50~45μm逐渐减小到5~10μm,片层厚度从2~3μm增加到20~25μm,多孔片层的致密度增大,复合材料的抗压强度也从0.05 MPa提高到0.12 MPa。当壳聚糖含量为13.3%、二氧化钛含量为85.7%、还原石墨烯含量为1%时,通过添加还原石墨烯对二氧化钛进行改性,所得的TiO_2/壳聚糖多孔复合材料在300 min时对甲基橙的光降解率由92.4%提高到97.0%。     

石墨烯负载铂催化剂的制备及稳定性

以天然石墨粉为原料,制备了氧化石墨（GO）,再以GO和氯铂酸（H₂PtCl₆）为前驱体,乙二醇作为溶剂和还原剂,通过浸渍还原法成功制备出铂和石墨烯的复合催化剂（Pt/GR）.利用X射线衍射仪、场发射扫描电镜和拉曼光谱仪对样品进行了形貌表征,结果表明Pt颗粒均匀分布在石墨烯的表面,相对于单质,负载有Pt的石墨烯表面更加褶皱且石墨烯片层更加分散.对Pt/GR进行电化学测试并与商用Pt黑催化剂进行对比,结果显示Pt/GR催化剂具有更高的电化学活性面积（ESCA）和更好的电催化性能,相对于Pt黑催化剂,Pt/GR具有更好的电化学稳定性.      

钒掺杂TiO_2粉体的制备及性能

严重的环境和能源问题推动了对以TiO2为主的半导体光催化材料的研究.金属阳离子掺杂TiO2,可以有效地提高光催化材料对可见光的响应及光催化性能.该文作者采用水相法制备以不同比率掺杂钒的TiO2粉体,并用H2SO4溶液浸渍处理,研究掺杂比率对粉体吸收光谱和光催化降解甲基橙的影响.结果表明:钒掺杂可以使TiO2粉体的光波长响应阈值移至600 nm左右,大大提高了TiO2对可见光的吸收;钒的掺杂比率(摩尔分数)为2.5%时,粉体在普通日光灯下照射6h,对甲基橙的降解率达到69%,高于纯TiO2粉体;硫酸修饰则提高了掺杂钒的TiO2粉体的光催化性.     

Photocatalytic activity of cerium-doped mesoporous TiO2 coated Fe3O4 magnetic composite under UV and visible light

A novel kind of magnetically separable photocatalyst of cerrium-doped mesoporous titanium dioxide coated magnetite (Ce/MTiO2/ Fe3O4) was prepared and its activities under UV and visible light were reported. The catalysts with Ce/MTiO2 shell and Fe3O4 core were pre-pared by coating photoactive Ce/MTiO2 onto a magnetic Fe3O4 core through the hydrolysis of tetrabutyltitanate (Ti(OBu)4, TBT) with pre-cursors of ammonium ceric nitrate and TBT in the presence of Fe3O4 particles. The MTiO2 shell was for photocatalysis, the Fe3O4 core was for separation by the magnetic field and the doped Ce was used to enhance the photocatalytic activity of MTiO2. The morphological, struc-tural and optical properties of the prepared samples were characterized by Brunauer-Emmett-Teller (BET) surface area, transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-vis absorption spectroscopy. The effect of cerrium-doped content on the photocatalytic activity was studied and the result revealed that 0.5 mol.% Ce/MTiO2/Fe3O4 exhibited highest photoactivity. The photocatalytic activities of obtained photocatalysts under UV and visible light were estimated by measuring the degradation rate of methylene blue (MB, 50 mg/L) in an aqueous solution. The results showed that the prepared photocatalyst was activated by visible light and used as effective catalyst in photooxi-dation reactions. In addition, the possibility of cyclic usage of the prepared photocatalyst was also confirmed. Moreover, Ce/MTiO2 was tightly bound to Fe3O4 and could be easily recovered from the medium by an external magnetic filed. So, the photocatalyst can be reused without any mass loss. It can therefore be potentially applied for the treatment of water contaminated by organic pollutants.     

TiO2-SiO2复合气凝胶的常压干燥制备及光催化降解含油污水活性

以钛酸四丁酯和正硅酸乙酯为原料,利用溶胶凝胶工艺制备出不同硅含量的TiO₂-SiO₂复合醇凝胶.结合老化液浸泡和小孔干燥工艺,在常压下干燥得到完整的TiO₂-SiO₂复合气凝胶块体.采用扫描电子显微镜、BET比表面积测试、X射线粉末衍射等测试手段对复合气凝胶的微观结构和物化性能进行了测试和表征.测试结果表明,复合气凝胶具有良好的性能,Ti和Si元素在气凝胶中分布均匀.随着SiO₂含量的增加,复合气凝胶的密度逐渐变小,比表面积增大,孔隙率增加,转变为锐钛矿相的相变温度升高.经高温煅烧晶化处理,复合气凝胶转变为锐钛矿相结构.以乳化后的渤海原油水溶液作为含油污水模拟溶液,测试了复合气凝胶对含油污水的催化降解性能.污水降解结果显示复合气凝胶对渤海原油污水具有较好的催化降解活性.在SiO₂摩尔分数低于30%时,随着硅含量的增加,复合气凝胶的光催化降解率升高;但当SiO₂摩尔分数高于30%后,继续增加SiO₂掺入量,反而造成复合气凝胶催化能力下降.对于SiO₂摩尔分数为30%的复合气凝胶,获得了最佳的催化降解效果,90 min催化降解率达95%.     

Synthesis and Photocatalytic Activity of TiO2/V2O5 Composite Catalyst Doped with Rare Earth Ions

TiO2/V2O5 catalyst doped with rare earth ions was prepared by sol-gel method. Titanium tetrapropoxide and vanadium pentoxide were used as precursor of the composite catalyst and rare earth ions were used as dopant. The crystal phases, crystalline sizes, microstructure, absorption spectra of doped composite catalyst were studied by XRD, EDS, FT-IR and UV-Vis. Photoactivity of the prepared catalyst under ultraviolet irradiation were evaluated by degradation of methyl orange （MO） in aqueous solution. It is shown that the prepared catalyst is composed of anatase and futile. The rare earth ions are highly dispersed in composite catalyst. All the doped catalysts appear higher photocatalytic activity than TiO2/V2O5 catalyst and catalyst doped with Ce^4＋ present the best activity to MO.     

石墨烯/二氧化锰复合材料的制备及其电化学性能

通过水热法在160℃条件下成功制备了手风琴状石墨烯/MnO₂复合材料.通过场发射扫描电镜、透射电镜、X射线衍射、X射线能量色散谱、BET法以及拉曼光谱对材料进行表征.结果表明,手风琴状二氧化锰与层状石墨烯之间具有十分高效的贴合,这种创新性设计有效地利用了石墨烯的高电导率、大比表面积以及二氧化锰的优秀赝电容行为.电化学测试结果给出在0.2 A·g^-1时,样品的比电容高达138 F·g^-1,数倍增强于单独的二氧化锰或石墨烯样品.     

石蜡/二氧化硅复合相变材料的制备及其性能

以石蜡为相变芯材,以正硅酸乙酯为硅源,在酸性条件下通过溶胶-凝胶法制备出石蜡/二氧化硅复合相变材料.应用傅里叶红外光谱、X射线衍射、扫描电镜、差示扫描量热法、热重法等手段对所制备复合相变材料的形貌、成分、热性能等进行了表征.实验结果表明,所制备的石蜡/二氧化硅复合相变材料的形貌是直径约为2μm的核/壳结构微球.当核/壳质量比为2∶1时,石蜡包覆率为66.3%,熔点为54.2℃,熔化焓为133.8 J·g^-1,凝固点为49.5℃,凝固焓为127.5 J·g^-1.与传统的有机高分子壳层材料相比,无机二氧化硅壳层材料具有更好的热导率,提升了复合相变材料的导热性能,且其不易燃烧,无腐蚀性,更加安全环保,有效拓展了相变材料在建筑保温和智能保温纺织物等领域的实际应用.     

包裹型SiO2/Al复合粉体的制备及烧结性能研究

为了克服金属陶瓷两相分布不均、界面不润湿和难以烧结致密等难题,采用球磨技术将增强相均匀包裹在基体材料表面,研究包裹型SiO₂/Al复合粉体的球磨制备工艺及其烧结性能,提高金属陶瓷的综合性能。结果表明,随着球磨时间的延长,SiO₂/Al复合粉体的比表面积先增大后减小,球磨6 h获得的复合粉体比表面积最大,达到8.1 m2·g?1。随着球料比的增大,SiO₂/Al复合粉体的比表面积先增大后减小,说明SiO₂包裹在Al粉表面的量呈现先增多再减少的趋势。随着球磨转速的增大,SiO₂/Al复合粉体比表面积先增大后减小。随着烧结温度的提高,SiO₂/Al金属陶瓷表面硬度先增高后降低,在烧结温度为900 ℃时,SiO₂/Al金属陶瓷的表面硬度达到最高。球磨时间为6 h,球料比为2:1,球磨转速为360 r·min?1,烧结温度900 ℃可以获得性能较佳的SiO₂/Al金属陶瓷。     

Preparation and performance research of Ce-TiO2/KL ball photocatalysts

The Ce-TiO2/KL （diatomite） ball photocatalyst was prepared and characterized based on the pretreated diatomite. The resuits showed that comparing with the crude diatomite, proper pretreatment could significantly improve its SiO2 purity and specific surface area. The surface of diatomite was clear with uniform pore structure and big pore size. With diatomite ball as carder, the supported Ce-TiO2/KL ball photocatalyst was prepared by sol-gel method. The photocatalytic performances of the supported Ce-TiO2/ KL ball and Ce-TiO2/KL powder photocatalysts under various preparation conditions were studied in view of photocatalytic degrada- tion rate of Rhodamine B （Rh B） solution. The degradation rate of the ball photocatalysts for Rh B reached 94.6% and could be reused for many times, which showed much better photocatalytic performance and stability than powder photocatalysts.     

Luminescence properties of dysprosium doped YVO4 phosphor

Trivalent dysprosium(Dy~(3+)) activated nanocrystalline yttrium vanadate(YVO_4) phosphor was synthesized via co-precipitation method. The prepared samples were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), optical absorption and photo luminescence(PL) techniques. The XRD patterns reveal the tetragonal crystalline phase. SEM images reveal that Dy doped YVO_4 nanocrystals are agglomerated. EDAX confirms the formation of YVO_4:Dy. FTIR spectrum shows two strong absorption bands at 459 and 761 cm~(-1). Optical absorption spectrum showed the surface defects in the as-prepared samples. The PL emission spectrum shows two characteristic emission bands at 485 and 575 nm. The strong yellow emission peak at 575 nm is assigned to ~4 F_(9/2)→~6 H_(13/2) hyper sensitive transition of Dy~(3+) ions, Study of CIE chromaticity diagram indicates the suitability of the phosphor for the development of yellow-green LEDs.     

类松果状NiMoO4/MnO2复合材料的合成及超级电容性能

以Na₂MoO₄·2H₂O、NiSO₄·6H₂O和MnO₂为原料, 采用水热法成功制备了类松果状NiMoO₄/MnO₂复合材料.通过X射线衍射、扫描电子显微镜、恒电流充放电、循环伏安和交流阻抗对材料进行表征.结果表明, MnO₂的最佳质量分数为10%, 所得NiMoO₄/MnO₂复合材料具有类松果状形貌, 其颗粒直径为200~600 nm, 且表面粗糙、多孔; 在1 A·g-1的电流密度下, MnO₂质量分数为0、5%、10%、15%、20%时, 所得复合材料NM0、NM5、NM10、NM15和NM20的放电比电容分别为260、248、650、420和305 F·g-1.在电流密度为10 A·g-1下, 最佳样品NM10复合材料的首次放电比容量为102 F·g-1, 经过100次循环后, 其放电比电容稳定在147 F·g-1.该性能的提高, 主要是由于MnO₂的引入弥补了NiMoO₄单一材料存在的不足, 从而达到协同增效的作用.