Preparations of TiO2 film coated on foam nickel substrate by sol-gel processes and its photocatalytic activity for degradation of acetaldehyde

Anatase TiO2 films were successfully prepared on foam nickel substrates by sol-gel technique using tetrabutyl titanate as precursor. The characteristics of the TiO2 films were investigated by XPS, XRD, FE-SEM, TEM and UV-Vis absorption spectra. The photocatalytic activities of TiO2 films were investigated by photocatalytic degradation reactions of gaseous acetaldehyde, an indoor pollutant, under ultraviolet light irradiation. It was found that Ni^2＋ doping into TiO2 films due to the foam nickel substrates resulted in the extension of absorption edges of TiO2 films from UV region to visible light region. The pre-heating for foam nickel substrates resulted in the formation of NiO layer, which prevented effectively the injection of photogenerated electrons from TiO2 films to metal nickel. The TiO2 films displayed high photocatalytic activity for the degradation of acetaldehyde, and were enhanced by calcining the substrates and coating TiO2 films repeatedly. The high activity was mainly attributed to the improvement of the characteristics of substrate surface and the increase of active sites on photocatalyst.     

溶胶-凝胶法制备分子筛／SiO2对氨氮的吸附研究

试验研究一种新型的复合材料对废水脱氮的能力,该种材料主要是由分子筛和几种有机和无机材料通过一定的条件合成,以达到节约成本提高利用率的作用。采用溶胶一凝胶法制备分子筛／SiO2复合材料,采用纳试试剂光度法为检测方法,考察了分子筛／SiO2在静态条件下对水中氨氮的吸附性能。通过几组对比试验,如分子筛单体脱氮的实验,分子筛／SiO2复合材料和二氧化硅单体脱氮的实验,实验中测定了时间、pH值、投加量等因素对脱氮除磷的影响,得出最佳吸附条件。结果表明,pH在4～7时对氨氮有较好的吸附性能,吸附符合Langmuir吸附模型,产生了复合效应。     

Effect of Ce doping of TiO2 support on NH3-SCR activity over V2O5-WO3/CeO2-TiO2 catalyst

CeO2–TiO2composite supports with different Ce/Ti molar ratios were prepared by a homogeneous precipitation method, and V2O5–WO3/CeO2–TiO2catalysts for the selective catalytic reduction（SCR） of NOx with NH3 were prepared by an incipient-wetness impregnation method. These catalysts were characterized by means of BET, XRD, UV–Vis,Raman and XPS techniques. The results showed that the catalytic activity of V2O5–WO3/TiO2 was greatly enhanced by Ce doping（molar ratio of Ce/Ti = 1/10） in the TiO2 support.The catalysts that were predominantly anatase TiO2 showed better catalytic performance than the catalysts that were predominantly fluorite CeO2. The Ce additive could enhance the surface adsorbed oxygen and accelerate the SCR reaction. The effects of O2 concentration, ratio of NH3/NO, space velocity and SO2 on the catalytic activity were also investigated. The presence of oxygen played an important role in NO reduction. The optimal ratio of NH3/NO was 1/1 and the catalyst had good resistance to SO2 poisoning.     

负载型活性炭/TiO2光催化降解苯酚的研究

在温和条件下(75℃和常压),通过在酸性水溶液中水解钛酸四丁酯并回流提高其结晶度,制备了锐钛矿型的TiO2.将此TiO2负载于粉末活性炭上,并用之来降解模拟废水苯酚.实验结果表明,该负载型催化剂的光催化效果要优于纯TiO2以及P25 TiO2加活性炭的混合体系.0.58g负载型催化剂降解0.4L浓度为100mg·L-1的苯酚溶液,经18W紫外灯光照6h后溶液中的苯酚去除率达到98%.同时,载体活性炭上吸附的苯酚量也随着光照时间逐渐减少,6h后残留的量仅为初始值的3.5%.     

Adsorption behavior of phosphate on Lanthanum（III） doped mesoporous silicates material

A series of lanthanum doped meosoporous MCM-41 (LaxM41, x is Si/La molar ratio) was prepared by sol-gel method. The surface structure of the materials was investigated with X-ray diffraction and N2 adsorption/desorption technique. The content of La in the materials was determined by ICP. It was found that the La content of La25M41, La50M41 and La100M41 was 7.53%, 3.89% and 2.32%, respectively. The phosphate adsorption capacities increased with increasing amount of La incorporation. With 0.40 g La25M41 99.7% phosphate could be removed. The effects of Si/La molar ratio, LaxM41 dose, pH, initial concentration of phosphate solution, co-ions on phosphate adsorption were also evaluated. The phosphate adsorption kinetics of LaxM41 could be well-described by the pseudo second-order model, and Langmuir isotherm fit equilibrium data much better than the Freundlich isotherm.     

Ag、N共掺杂TiO2漂浮型催化剂的光催化性能

采用溶胶-凝胶法,制备出银氮共掺杂TiO_2负载膨胀珍珠岩的催化剂,通过电子显微镜扫描(SEM)、比表面积及孔径分析(BET)和X射线衍射(XRD)对其结构进行表征,并以罗丹明B溶液为目标降解物,研究所制备催化剂的光催化性能。结果表明:复合材料成功负载了Ag和N元素,且掺杂增强了TiO_2对可见光的响应能力;复合材料存在少量的微孔和大孔,同时存在大量的介孔;掺杂氮后材料的光催化活性大幅度提高,继续掺杂Ag后光催化活性进一步提高,当n(Ag)∶n(Ti)=0. 50%时光催化性能最佳,4 h内处理罗丹明B降解率可达99. 3%,材料的光催化反应符合一级反应动力学方程,表明其在环境净化实际应用中的巨大潜力。     

铜锰镧铈复合催化剂的制备及其降解对二甲苯的机制

采用溶胶凝胶法制备了镧掺杂的铜锰镧铈催化剂,研究了其对对二甲苯的催化性能.通过BET、SEM、H₂-TPR、XRD和XPS等对不同元素比例的催化剂进行表征,探讨了催化剂结构和性能的关系;同时,研究了不同影响因素（初始浓度、空速、O₂含量和混合物）对其催化氧化性能的影响;最后,利用FT-IR、XRD和 GC-MS对降解产物进行分析,探究了其催化降解对二甲苯的机理.结果表明,La掺杂增加了催化剂的比表面积和孔体积,以及表面氧含量,抑制了晶体形成,增强了催化活性.Cu-Mn-La-Ce（1：2：1：1）催化剂性能最好,在初始浓度为600 mg·m^-3,空速为15000 h^-1,20% O₂的条件下,其T₉₀为230 ℃.对二甲苯的降解率随着初始浓度、空速的增加而降低,随着O₂含量的增加而增加.气流中混入苯提高了对二甲苯的降解率.对二甲苯催化反应后催化剂表面的 O—H、C＝O、C—H和金属—氧键都相应减少,降解中间产物主要为对甲基苯甲醛和对甲基苯甲酸.降解反应涉及MVK机理,对二甲苯先氧化成对甲基苯甲醛,再氧化成对甲基苯甲酸,最终生成CO₂、H₂O.     

V~(5+)/TiO_2-SiO_2-GF复合光催化剂制备及降解甲醛的研究

采用溶胶-凝胶法制备了纯TiO2、TiO2-SiO2、V5+/TiO2-SiO2光催化剂,并分别负载于玻璃纤维布上,利用X射线衍射(XRD)和比表面及孔隙度(BET)分析技术对样品进行了表征。以甲醛的降解率来评价复合光催化剂的光催化活性。结果表明:玻璃纤维布预处理方式、TiO2与SiO2的复合配比、V的掺杂量、煅烧温度对纳米TiO2的光催化活性有影响。V5+/TiO2-SiO2复合光催化剂比表面积为143.74 m2/g,晶粒粒径为16.9 nm。     

TiO_2/ACFs催化剂光催化降解染料废水活性研究

以活性炭纤维为载体,采用溶胶-凝胶法制备得到了活性炭纤维负载二氧化钛光催化剂(TiO2/ACFs),并且以亚甲基蓝为模型化合物模拟研究了活性炭纤维负载二氧化钛光催化剂(TiO2/ACFs)对染料废水的光催化活性。通过扫描电镜(SEM)、XRD等表征方法对活性炭纤维负载二氧化钛光催化剂(TiO2/ACFs)的结构进行了研究。SEM表征显示,大部分二氧化钛以膜的形式均匀地包裹在活性炭纤维丝上,二氧化钛膜层的厚度大约为330 nm,还有一部分TiO2是以颗粒的形式负载在活性炭纤维上。FT-IR分析可知,ACF与TiO2之间有Ti—O—C键生成,说明TiO2与ACF结合牢固,TiO2不易脱落。通过对亚甲基蓝降解可知当煅烧温度为500℃时,TiO2/ACF的光催化性能最好,通过对比发现500℃煅烧制备的催化剂也具有最好的循环使用性能,经过4次循环后该催化剂对亚甲基蓝的去除率仍达到90.2%。     

纳米复合ZnO-TiO2晶体的制备及其光电催化性能研究

采用溶胶-凝胶法制备了纳米复合半导体ZnO-TiO2薄膜,并进行了结构和光电催化性能的测试.TiO2薄膜对五氯酚溶液的光电催化降解结果表明当输入正向偏压后,其光催化性能有较大提高.由于ZnO的掺入,半导体薄膜电极的光吸收能力增强;同时,Zn2+可能作为光生载流子的浅俘获中心,导致表面界面电荷转移加速,从而延长光生电子/空穴对的寿命并抑制其复合,有效地提高了TiO2薄膜光电催化活性.