锐钛矿SO42-/TiO2纳米光催化剂的制备及其性能

采用溶胶-凝胶-浸渍法制备了锐钛矿型SO42-/TiO2纳米光催化剂,并通过X射线衍射(XRD)、BET比表面积测量和透射电镜(TEM)对其进行了表征。以对苯二甲酸作为探针分子,结合化学荧光技术研究了光催化剂表面羟基自由基的生成;在紫外和可见光的照射下,以甲基橙为光催化反应的模型化合物,研究了锐钛矿型SO42-/TiO2纳米光催化剂的光催化活性。结果表明:SO42-负载使锐钛矿TiO2的比表面积增加,吸附量增加,光催化活性提高;SO42-/TiO2纳米光催化剂的羟基自由基的生成速率越大,催化剂的催化活性越高;浸渍液H2SO4的浓度对SO42-/TiO2纳米光催化剂的吸附量、羟基自由基的生成速率和催化活性有一定的影响,H2SO4的最佳浓度为0.2mol/L。     

介孔SO_4~(2-)/TiO_2固体超强酸的制备与表征

以工业硫酸钛液为原料,分步水解制得吸附硫酸根的介孔偏钛酸,焙烧得到介孔SO42-/TiO2固体超强酸。用Hammett指示剂法、XRD、BET和FI-IR等多种手段对催化剂进行了表征;以乙酸乙酯的合成为模型反应,考察了催化活性。结果表明所制备的SO42-/TiO2催化剂是介孔结构;随着焙烧温度的升高和SO42-含量的增加,其比表面积和酸强度都先增大后减小,最高酸强度H0=-14.52,最大比表面积为192m2/g;酸强度及硫含量与催化活性都有着密切联系,在500℃下焙烧,硫含量为2.7%时,催化活性最高。     

纳米固体超强酸 SO42- /TiO2的氧敏特性研究

采用溶胶-凝胶法制备了TiO2,再用浸渍法制备纳米固体超强酸SO42-/TiO2,用XRD、TEM、IR、XPS和比表面测量等方法进行表征。结果表明纳米固体超强酸SO42-/TiO2的粒径(≤30nm)比TiO2小,并且具有很大的比表面积,Ti4+离子与SO42-的结合形式为无机双齿螯合型结构,酸强度用乙酸乙脂合成模型实验测定,确定纳米SO42-/TiO2为超强酸(SO42-/TiO2脂产率≥H2SO4脂产率)。利用固体超强酸SO42-/TiO2和纯TiO2纳米粉体分别制作成厚膜型气敏元件,固体超强酸SO42-/TiO2氧敏元件的灵敏度和工作温度等技术指标均优于纯TiO2,还进一步讨论了其氧敏特性和结构之间的关系。     

SO4^2-／ZrO2-SiO2的制备及其催化性能研究

用共沉淀法制备了SO4^2-／ZrO2-SiO2固体酸催化剂，通过XRD、BET、IR、SEM等综合实验手段考察了SiO2的加入量不同对固体酸的晶体结构的影响，并以乙酸正丁酯的酯化反应为探针实验考察了SO4^2-／ZrO2-SiO2的催化性能。结果表明，SiO2的加入抑制了ZrO2晶型的转变，提高了催化剂的活性。     

介孔SO2-4/TiO2固体超强酸的制备与表征

以工业硫酸钛液为原料,分步水解制得吸附硫酸根的介孔偏钛酸,焙烧得到介孔SO2-4/TiO2固体超强酸.用Hammett指示剂法、XRD、BET和FI-IR等多种手段对催化剂进行了表征;以乙酸乙酯的合成为模型反应,考察了催化活性.结果表明所制备的SO2-4/ TiO2催化剂是介孔结构;随着焙烧温度的升高和SO2-4含量的增加,其比表面积和酸强度都先增大后减小,最高酸强度H0=-14.52,最大比表面积为192m2/g;酸强度及硫含量与催化活性都有着密切联系,在500℃下焙烧,硫含量为2.7%时,催化活性最高.     

介孔SO42-/TiO2的一步法制备及其光催化性能

通过对TiOSO4溶液热水解用一步法制备出大比表面积、高活性的介孔SO42-/TiO2光催化剂.用低温氮吸附-脱附等温线、XRD、Hammett指示剂、艾氏卡等方法对SO42-/TiO2催化剂进行了表征,以亚甲基蓝的光催化氧化降解反应考察了催化剂的光催化性能.结果表明,在焙烧过程中硫酸根和偏钛酸孔壁上的自由羟基键合,不仅有效地抑制了TiO2晶粒的长大和晶相转变,而且起到了孔结构形成的导向及支撑作用,使TiO2保持了介孔结构、较高的比表面积和锐钛矿相,同时S=O键的强电子诱导效应还使邻近的Ti成为超强酸中心,促进了TiO2光生电子-空穴对的分离,延长了电子-空穴对的寿命,从而有效地提高了TiO2的光催化活性.     

TiO2/ACF光催化再生复合材料的研究进展

总结近年来在TiO2与活性碳纤维复合光催化剂的合成方法、结构与性能,及对室内挥发性有机物光催化降解方面的研究,分析TiO2/ACF复合光催化剂对有机物吸附、富集、光催化、原位再生的过程,探讨活性碳纤维吸附材料对提高TiO2光催化剂量子产率的作用机制,认为低浓度污染物在催化剂表面的吸脱附速率提高是TiO2/ACF复合光催化剂具有较高降解能力的关健因素.     

介孔SO4^2-／TiO2固体超强酸的制备与表征

以工业硫酸钛液为原料，分步水解制得吸附硫酸根的介孔偏钛酸，焙烧得到介孔SO4^2-／TiO2固体超强酸。用Hammett指示刑法、XRD、BET和FI—IR等多种手段对催化剂进行了表征；以乙酸乙酯的合成为模型反应，考察了催化活性。结果表明所制备的SO4^2-／TiO2催化剂是介孔结构；随着焙烧温度的升高和SO4^2-含量的增加，其比表面积和酸强度都先增大后减小。最高酸强度H0=14．52，最大比表面积为192m^2／g；酸强度及硫含量与催化活性都有着密切联系。在500℃下焙烧，硫含量为2．7%时，催化活性最高。     

TiO2-SiO2复合薄膜光催化活性的研究进展

TiO2-SiO2复合薄膜相对纯TiO2薄膜更有利于提高光催化活性,针对TiO2-SiO2复合薄膜在提高光催化活性方面表现的优异性能,论述了其提高光催化活性的机理。根据近年来国内外TiO2-SiO2复合薄膜的研究现状,对溶胶-凝胶法、离子自组装成膜技术、射频磁控共溅射法、液相沉积法、化学气相法等制备方法的研究进展进行了综述,并对其优缺点进行了比较和评述。展望了TiO2-SiO2复合薄膜进一步研究的方向和需要解决的问题。     

SO42-/ZrO2固体酸的超声快速制备及表征

在沉淀和浸渍过程中都分别施加超声波快速制备了SO42-/ZrO2固体酸。利用XRD、FT-IR、TG-DTA、BET和NH3-TPD等方法对样品进行分析表征,探讨超声作用对固体酸中ZrO2晶粒粒径、样品比表面积、热稳定性和酸性等的影响。结果表明,超声制备SO42-/ZrO2形成超强酸结构的适宜焙烧温度为550℃。与常规法相比,超声波的引入能获得较小晶粒的ZrO2,并强化了浸渍过程中与高价硫的结合,所得样品比表面积增大,并可以提高催化剂的酸强度以及改变催化剂酸量分布。     

固体超强酸SO42-/TiO2-Al2O3的制备及其催化合成冰片

采用溶胶-凝胶法和浸渍法制备了系列SO_4~(2-)/TiO_2-Al_2O_3固体超强酸催化剂,运用XRD、NH_3-TPD、FT-IR、PyFTIR、XPS、SEM等技术手段,研究了复合催化剂材料的结构与性质,初步探讨了固体超强酸SO_4~(2-)/TiO_2-Al_2O_3催化剂的构效关系,得到适宜的催化剂制备条件为:n(TiO_2)/n(Al_2O_3)=1∶2、硫酸浸渍浓度1mol/L、催化剂焙烧温度500℃。考察了物料物质的量比、催化剂用量、反应时间等对催化合成冰片的影响。结果表明,在物料物质的量比为1∶0.4,催化剂用量为α-蒎烯质量的7%,采用程序升温方式(65℃-1h,75℃-4h,90℃-1h)加热的条件下,固体超强酸SO_4~(2-)/TiO_2-Al_2O_3催化剂的催化活性最高,α-蒎烯的转化率高达100%,龙脑的收率高达59.74%,SO_4~(2-)/TiO_2-Al_2O_3固体超强酸催化剂在重复使用6次的条件下,α-蒎烯的转化率均不变,龙脑的收率下降2.99%,催化剂的重复使用性良好。     

绿色阻垢剂MA/SSS聚合物的表征及其阻垢性能

为丰富绿色水处理剂聚环氧琥珀酸(PESA)的功能性官能团,优化其阻垢性能,以马来酸酐(MA)和苯乙烯磺酸基盐(SSS)为原料,利用固体超强酸SO_4~(2-)/TiO_2-SiO_2为催化剂,熔融聚合了新型含苯乙烯磺酸基聚合物(MA/SSS)。采用红外光谱(FT-IR)和凝胶渗透色谱(GPC)对聚合物进行表征;采用静态试验考察了其CaCO_3阻垢效果,并用扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)测试探讨了MA/SSS的CaCO_3阻垢机理。结果表明:MA/SSS具有羧基、磺酸基和苯环等一系列特征峰,其数均相对分子量Mw为4 174;在相同条件下,与PESA相比,MA/SSS适用于高钙环境且用量小。机理研究表明,MA/SSS干扰或抑制了球霰石进一步结晶生长,形成无定形沉渣。     

Preparation of mesoporous titania solid superacid and its catalytic property

Mesoporous titania (TiO(2)) was synthesized by hydrothermal method using cetyltrimethyl ammonium bromide (CTAB) as a template and using anhydrous ethanol and tetra-n-butyl titanate (TBOT) as raw materials. Mesoporous titania solid superacid and nanosized titania solid superacid catalysts were prepared by wet impregnation method. The structure and property of as-prepared samples were characterized by means of XRD, FT-IR and N(2) physical adsorption. The esterification of salicylic acid with isoamyl alcohol and the condensation of cyclohexanone with ethylene were used as model reactions to test the catalytic activities of the catalysts. On the other hand, the comparison of catalytic activities of the prepared solid superacid catalysts and the conventional liquid acid H(2)SO(4) was also carried out under the same experimental conditions. The results show that the catalytic activities of the prepared solid superacid catalysts were higher than that of the conventional liquid acid H(2)SO(4), and that the catalytic activity of mesoporous TiO(2) solid superacid is the highest among the three catalysts. Mesoporous TiO(2) solid superacid is a good catalyst for the synthesis of isoamyl salicylate or cyclohexanone ethylene ketal.     

Influence of Microwave Radiation on Properties and Structure of Fe_2O_3/SO_4~(2-) Solid Superacid Catalyst

The microwave radiation method was introduced to prepare the Fe_2O_3/SO solid superacid.Its structure and properties were investigated by means of X-ray diffraction and infrared spectrum analyses as well as measurement of magnetic susceptibility and rate of esterification. The structure of the superacids prepared in microwave field can be crystalline or non-crystalline, the latter has not been reported yet in literatures. Comparing with the traditional superacid, the non-crystalline Fe2O3/SO superacid prepared in microwave field has the highest magnetic susceptibility and catalytic activity. The di-coordination of Fe2O3 and SO and the S=O bi-bond were reinforced by microwave radiation, which is favorable for increasing the acid intensity of the Fe2O3/SO catalyst     

Simple and effective synthesis of methoxy-dimethylbenzene from electrochemical oxidation of p-xylene in methanol solvent catalyzed by SO(4)(2-)/ZrO(2)-M(x)O(y)

A series of composite solid superacid catalysts SO(4)(2-)/ZrO(2)-M(x)O(y) (M=Ti, Ni, Si) were prepared and investigated by means of Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). All catalysts exhibit good catalytic activity in the electrochemical reaction of p-xylene with methanol assisted with a pair of porous graphite plane electrodes and the selectivity of main products higher than 90% were observed. In particular, SO(4)(2-)/ZrO(2)-SiO(2) catalyst exhibited excellent catalytic activity. According to the experimental results, a possible free radical reaction mechanism confirmed by XPS and ultraviolet-visible (UV-vis) spectra was proposed. It may be concluded that a simple and feasible electrochemical catalytic oxidation reaction at room temperature and standard atmosphere may be possible.     

失活钒钛基SCR催化剂性能表征及其再生

主要研究了钒钛基脱硝催化剂失活机理及再生。采用SEM、EDS、XRD、BET等手段对国内某家燃煤火电厂运行20000h的SCR脱硝催化剂进行表征,然后使用0.5mol/L的硫酸和0.01mol/L的氢氟酸对运行过的催化剂进行了清洗再生并通过烟气模拟-催化剂活性测试系统考察了催化剂的脱硝活性。结果表明,相比于新鲜催化剂,运行后的催化剂活性明显下降,孔容和比表面积有所下降,其表面存在着组成复杂的飞灰,飞灰主要成分为SiO2;采用0.01mol/L氢氟酸溶液清洗能够明显恢复催化剂的脱硝活性,这是因为氢氟酸可以有效清除失活催化剂表面的SiO2。     

固体超强酸于多孔高硅氧纤维的负载及其在酯化中的应用

以溶胶浸渍法,将SO42-/ZrO2固体超强酸负载到由酸沥滤工艺制备的多孔高硅氧纤维上,并用于催化合成乙酸正丁酯。研究结果表明,该催化剂具有用量少,酯收率较高,产物易于分离等优点;而且使用寿命长,重复用于5次合成后,酯化率仍高于70%。     

医用NiTi合金表面溶胶-凝胶法制备TiO2-SiO2薄膜

采用溶胶－凝胶法在ＮｉＴｉ形状记忆合金表面制备了ＴｉＯ_２－ＳｉＯ_２复合薄膜,在提高医用ＮｉＴｉ合金的抗腐蚀性方面,收到了显著的效果．运用电化学方法对不同组成的ＴｉＯ_２－ＳｉＯ_２薄膜在模拟体液中的腐蚀行为进行了研究,结果表明,随薄膜中 Ｔｉ／Ｓｉ比的增加,ＴｉＯ_２－ＳｉＯ_２薄膜的抗腐蚀性增强．划痕试验表明 ＴｉＯ_２－ＳｉＯ_２（Ｔｉ／Ｓｉ＝４：１）膜与ＮｉＴｉ合金基体具有较高的界面结合强度．用原子力显微镜（ＡＦＭ）对ＴｉＯ_２－ＳｉＯ_２薄膜的表面形貌及表面粗糙度进行观察和分析,解释并讨论了ＴｉＯ_２－ＳｉＯ_２薄膜的配方组成与其抗腐蚀性的关系,ＳｉＯ_２含量较少时,薄膜结构致密,膜层均匀平滑,且膜基结合力好,作为医用ＮｉＴｉ合金的表面保护层,可以使其耐腐蚀性有显著提高．     

Aqueous Cr(VI) photo-reduction catalyzed by TiO2 and sulfated TiO2

TiO(2) and sulfated TiO(2) (SO(4)(2-)/TiO(2)) catalysts with different textural properties were prepared under different calcination temperatures and the photo-reduction of Cr(VI) to Cr(III) catalyzed by these catalysts was investigated. For the photocatalytic reduction of Cr(VI), the photocatalytic activities of the TiO(2) samples were found to be strongly dependent of the calcination temperature and TiO(2) calcined at 400 degrees C showed a higher catalytic activity compared to other TiO(2) catalysts. In contrast, sulfation of TiO(2) stabilized the catalytic activities of SO(4)(2-)/TiO(2) catalysts. At low calcination temperature, SO(4)(2-)/TiO(2) catalysts exhibited catalytic activities almost comparable with that of TiO(2) and the catalytic activities of SO(4)(2-)/TiO(2) catalysts were markedly higher than TiO(2) under high calcination temperature. In addition, the removal of surface SO(4)(2-) of SO(4)(2-)/TiO(2) catalyst led to a marked decrease of the catalytic activity for Cr(VI) photo-reduction, suggesting that the presence of surface SO(4)(2-) provided an acid environment over the catalyst surface and favored the photo-reduction of Cr(VI).