N与La共掺杂纳米TiO_2/电气石复合材料的制备及其光催化性能

采用超声辅助溶胶-凝胶法,以钛酸丁酯为原料,尿素为N源,硝酸镧为La源,制备了N与La共掺杂纳米TiO_2/电气石复合材料。采用XRD、UV-Vis、SEM-EDS和XPS对复合材料的结构和性能进行了表征。以2,4,6-三硝基甲苯作为目标污染物,考察了N与La共掺杂纳米TiO_2/电气石复合材料的光催化活性及再生利用性能。结果表明:N与La共掺杂并负载电气石后,两者协同作用使TiO_2晶粒更加细化,光吸收范围向可见光区拓展,N与La共掺杂纳米TiO_2/电气石复合材料具有良好的光催化活性和再生利用性能,且在模拟可见光照射条件下对2,4,6-三硝基甲苯具有良好的去除效果。     

氮-镨共掺杂TiO_2的制备及催化性能研究

为了提高TiO_2的光催化性能,采用溶胶凝胶法制备了N和稀土Pr共掺杂TiO_2光催化剂。用XRD、SEM和紫外-可见光分度计对样品进行表征,并考察了掺杂量、煅烧温度和晶型对TiO_2光催化性能的影响。研究发现N-Pr混合改性的TiO_2的催化活性均高于未改性的,5%的N和0.5%的Pr混合掺杂并经500℃锻烧后,样品为单一的锐钛矿相且粒径分布较窄,在模拟灯光照射下表现出较高的光催化活性和降解甲基橙溶液的能力,在80 min内使甲基橙溶液的降解率达到了99%。     

N掺杂纳米TiO_2/电气石复合材料的制备及其光催化性能

以钛酸丁酯为前驱体,尿素为N源,电气石为载体,采用超声辅助溶胶-凝胶法制备N掺杂纳米TiO_2/电气石复合材料。采用XRD,FT-IR,UV-Vis DRS,SEM,EDS等测试技术对复合材料的结构和性能进行表征。分别考察煅烧温度、掺N量、电气石添加量、催化体系等因素对复合材料光催化性能的影响。结果表明:在煅烧温度为500℃,N掺杂量为5%(摩尔分数),电气石添加量为10%(质量分数),催化剂用量为3g/L,500W紫外灯照射条件下,N掺杂纳米TiO_2/电气石复合材料光催化降解TNT(10mg/L)的效果最佳,且具有良好的再生利用性能。     

煅烧温度对溶胶-微波法制备Pr掺杂纳米TiO_2及其光学性能的影响

以钛酸丁酯和硝酸镨为原料,采用溶胶-微波法合成纳米Pr-TiO_2。采用X射线衍射、扫描电镜、X射线能谱和紫外-可见光等手段研究了煅烧温度对其晶体结构、表观形貌及光学性能的影响。结果表明:镨的掺杂对纳米TiO_2的形貌及光催化性能有显著影响。镨的掺杂抑制了晶粒的生长,抑制了晶型由锐钛矿相向金红石相的转变。随着煅烧温度的增加,纳米TiO_2团聚加剧,比表面积降低,锐钛矿相逐渐向金红石相转变,并且光催化过程中产生的活性羟基量逐渐减少,光催化活性逐渐降低,其中当煅烧温度为500℃时所合成的纳米Pr-TiO_2的光催化效果最优。Pr掺杂TiO_2提高了可见光的利用率并且红移了50nm。     

ACF负载N掺杂TiO_2光催化材料的制备及性能研究

以尿素为氮源,采用溶胶-凝胶浸渍法将N掺杂TiO_2负载于粘胶毡上,然后在400℃下煅烧活化,制得了负载N掺杂TiO_2的活性碳纤维毡(记作NxTiO_2/ACF)。运用扫描电子显微镜(SEM)、X射线衍射(XRD)和红外光谱(ATR/FT-IR)等手段对光催化材料进行了表征,以亚甲基蓝为目标降解物,考察了不同N掺杂量和重复使用次数对材料光催化性能的影响。SEM和ATR/FT-IR测试表明N掺杂TiO_2均匀的负载到ACF上;XRD结果说明在400℃煅烧的N掺杂TiO_2晶型为锐钛矿型。光催化结果显示当N/Ti摩尔比为0.5时,材料的光催化性能最佳;此方法制备的光催化材料可以重复使用,重复使用5次时光催化效率仍然保持在80%以上。     

氮掺杂改性TiO_2多孔薄膜光催化降解4-硝基苯酚

本文采用溶胶-凝胶法制备了N掺杂TiO_2光催化剂,并对N掺杂TiO_2进行了改性,分别以P25、N掺杂TiO_2、改性的N掺杂TiO_2为原料,通过逐步研磨、旋转涂膜以及高温煅烧制得三种多孔薄膜,并对其进行了表征。场发射扫描电子显微镜(FESEM)观察结果显示,煅烧后薄膜呈现显著的多孔结构。以4-硝基苯酚(4-NP)溶液为目标污染物,研究紫外光下TiO_2多孔薄膜的光催化性能,确定最佳降解条件,并研究了薄膜耐用性以及三种薄膜对4-NP的光催化性能的比较。结果表明,三种多孔薄膜中,改性N掺杂TiO_2多孔薄膜光催化性能最佳,10mg/L的4-NP溶液吸附30min,在pH=2条件下180min,降解率达到了90%以上,改性N掺杂TiO_2多孔薄膜单次降解180min,循环使用4次的降解率仍接近80%,显示了薄膜具有较好的可耐用性。     

生物模板法制备TNS/C复合材料及其光催化性能研究

以生物质材料玉米杆作为模板和碳源,将钛酸丁酯浸渍于玉米杆中,通过高温煅烧原位制备了的TiO_2纳米片/碳(TNS/C)复合材料。生物质在煅烧过程中形成碳骨架并固载了TiO_2,使其形成纳米片层结构,形成了TNS/C异质结。以在紫外下对苯酚的去除率和矿化率评价光催化活性,考察了不同煅烧温度和模板用量对TNS/C复合材料光催化性能的影响,结果显示在煅烧温度为700℃,模板用量为0.75 g条件下制备的TNS/C复合材料具有最佳的光催化性能,适量的碳材料有助于提高光生电子空穴的分离效率,进而大幅提高了材料在对苯酚的去除效果和光催化矿化苯酚的能力。     

Mn掺杂TiO_2负载竹质活性炭纤维的制备及可见光光催化性能研究

采用溶胶-凝胶法和浸渍法制备Mn掺杂TiO2负载竹质活性炭纤维(Mn/Ti-BACF)光催化复合材料,利用扫面电镜(SEM)、X射线衍射仪(XRD)、傅立叶变换红外光谱(FT-IR)、紫外-可见光分光光度计(UV-Vis)等考察了Mn掺杂量对Mn/Ti-BACF复合材料结构和可见光光催化性能的影响。结果发现,Mn掺杂改善了TiO2在竹质活性炭纤维表面的负载;Mn离子的掺杂并没有改变样品基材的碳网结构,也未出现新的Mn—O的特征吸收峰。随着Mn掺杂浓度的增加,Mn/Ti-BACF样品中TiO2粒径逐渐减小,可见光下的吸光度先增加后减少。当n(Mn)∶n(Ti)=1∶200时,样品在可见光下对亚甲基蓝的降解率达到了97.7%。     

S掺杂TiO_2/硅藻土复合光催化材料的制备及其特性研究

以钛酸四丁酯为前驱体,以硫脲为S源,硅藻土为载体,用超声辅助溶胶-凝胶制备了S掺杂纳米TiO_2/硅藻土复合光催化剂。采用差示量热扫描分析仪(DSC)、傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)、紫外可见漫反射(UV-Vis)、扫描电子显微镜(SEM)、能谱分析(EDS)等测试技术对复合材料的结构进行表征。选用煅烧温度,不同S掺杂量,不同TiO_2负载量及重复使用等作为影响复合材料光催化性能的因素进行探究。结果表明,当煅烧温度为500℃,S掺杂量为7.5%,TiO_2负载量为40%的条件下制备的催化剂有着最佳催化活性,在500W紫外灯照射下,复合材料的光催化去除TNT(50mg/L)的效果最佳,达到86.3%,且复合材料具有良好再生利用性能。     

高光催化性能的二氧化钛纳米管—氧化石墨烯杂化材料（英文）

以金红石型TiO_2、氧化石墨烯和氢氧化钠为反应剂,通过水热合成法制备了TiO_2纳米管-氧化石墨烯复合材料,并研究复合材料制备过程中水热温度、煅烧温度对制备材料结构性能的影响关系。结果发现,TiO_2纳米管-氧化石墨烯复合材料比纯TiO_2纳米管具有更好的光催化性能。石墨烯有利于TiO_2纳米管的形成,而且存在一个优化的加强光催化性性能的煅烧温度。TiO_2纳米管-氧化石墨烯复合材料在煅烧过程中,氧化石墨烯的还原与逐渐损失同TiO_2纳米管的结晶动态平衡,可能是其中存在优化煅烧温度的原因。同时分析了TiO_2纳米管-氧化石墨烯复合新材料的复合机理。     

H(2)O(2)-sensitized TiO(2)/SiO(2) composites with high photocatalytic activity under visible irradiation

TiO(2)/SiO(2) composite photocatalysts were prepared by depositing of TiO(2) onto nano-SiO(2) particles. X-ray diffraction (XRD), transmission electron micrograph (TEM), Raman spectrometer, UV-Vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy (FT-IR) were employed to characterize the properties of the synthesized TiO(2)/SiO(2) composites. These results indicated that the products without calcination were amorphous, and calcination could enhance the crystallinity of TiO(2). Increases in the amount of TiO(2) would decrease the dispersion in the composites. H(2)O(2)-sensitized TiO(2)/SiO(2) composite photocatalysts could absorb visible light at wavelength below 550 nm. The photocatalytic activity of as-prepared catalysts was characterized by methyl-orange degradation. The results showed the uncalcined composite photocatalysts with amorphous TiO(2) exhibited higher photocatalytic activity under visible light, and the activity of catalysts with TiO(2) content over 30% decreased with increasing of TiO(2) content. Increases in the calcination temperature and TiO(2) content promote the formation of bulk TiO(2) and result in a decrease in activity.     

Low temperature synthesis and visible light driven photocatalytic activity of highly crystalline mesoporous TiO2 particles

Mesoporous TiO2 powder materials with a high crystallinity have been prepared by evaporation induced self assembly (EISA) process using titanium tetraisopropoxide (TTIP) and pluronic P123 surfactant (EO20PO70EO20) as titanium source and structure-directing reagent, respectively. The prepared materials were characterized by low and wide-angle X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), optical absorption, and N2 adsorption-desorption experiments. The crystallinity of the materials was controlled by varying the calcination temperature. The resulting TiO2 materials showed highly crystalline structure with uniform particle size which increases from 11.8 to 23.8 nm with increasing the calcination temperature from 400 to 600 degrees C, respectively, whereas the specific surface area decreases from 125 to 40 m2/g. TEM and XRD results revealed that the calcination temperature of 600 degrees C is the best condition to obtain highly crystalline mesoporous TiO2. The photocatalytic activity of the TiO2 mesoporous materials with different crystallinity and textural parameters has been studied in the decomposition of methylene blue (MB) dye molecules under visible light irradiation. Among the mesoporous TiO2 materials studied, the material with the highest crystallinity, prepared at 600 degrees C, showed the best photocatalytic performance in the decomposition of MB under visible light in a short time.     

Enhanced photocatalytic activity of C-N-codoped TiO2 films prepared via an organic-free approach

An organic-free sol-gel method was developed to synthesize crack-free, high surface roughness and visible-light-active C-N-codoped TiO(2) films. These films were subsequently evaluated for its photodegradation efficient using stearic acid as the model pollutant compound. The current approach avoids the use of hazardous organic solvents and employs carbon black as the carbon source as well as a template to increase the surface roughness. The presence of carbon and nitrogen species in TiO(2) was studied and discussed. The concentrations of carbon and nitrogen dopants in the TiO(2) films were affected by calcination temperature and the concentration of carbon black. Optimal visible light photocatalytic activity was observed for C-N-codoped TiO(2) film at 10.0 wt.% C, which was more than double that of the N-doped TiO(2) film. The enhancement in visible light photocatalytic activities of the C-N-codoped TiO(2) films was attributed to the synergistic effects of carbon and nitrogen dopants, and high surface roughness of the prepared films.     

ZnO/CNTs复合材料的制备、表征及光催化性能

采用水热法制备了一系列氧化锌和碳纳米管的复合材料(ZnO/CNTs),详细考察了碳纳米管的含量对复合材料光催化性能的影响。利用X射线衍射仪、紫外-可见漫反射吸收光谱、扫描电子显微镜、X射线能谱、透射电子显微镜、X射线光电子能谱和氮气吸附-脱附等测试手段对样品的结构、形貌和光学性质进行了表征,并用亚甲基蓝溶液模拟污染物,评价了ZnO/CNTs复合材料的光催化性能。结果表明:添加CNTs提高了ZnO的比表面积,增强了ZnO的可见光吸收。ZnO/CNTs复合材料较纯ZnO具有更高的光催化活性,并且随着CNTs含量的增加,ZnO/CNTs复合材料的光催化活性呈先增加后减小的趋势。当CNTs的含量为0.3%(质量分数)时,ZnO/CNTs复合材料的光催化活性最高,经过50 min光照后,亚甲基蓝的降解率达到了96.2%。     

Photodegradation of rhodamine B under visible light by bimetal codoped TiO2 nanocrystals

In the search for efficient photocatalysts working under visible light, we have investigated the effect of metal ions (Bi/Co, Fe/Co) codoping on the photocatalytic activity of TiO(2) prepared by stearic acid gel method. UV-vis spectra revealed that doped Co enhanced the absorbency of TiO(2) under visible light, and Bi/Co codoped TiO(2) showed higher absorbance than Fe/Co codoped TiO(2). The photoreaction based on the prepared samples for photodegradation of 20mg/l rhodamine B solution was examined. The results showed that Fe(0.1%)/Co(0.4%) codoped TiO(2) had the highest photoactivity among all as-prepared samples under visible light, though less absorbency of visible light, indicating that the photoactivity not only benefits from absorbency but also relates to the cooperative effect of the two dopants.     

Realizing visible-light-induced self-cleaning property of cotton through coating N-TiO2 film and loading AgI particles

The visible-light-induced self-cleaning property of cotton has been realized by coating N-TiO(2) film and loading AgI particles simultaneously. The physical properties were characterized by means of XRD, SEM, TEM, XPS, and DRS techniques. The visible light photocatalytic activities of the materials were evaluated using the degradation of methyl orange. In comparison with TiO(2)-cotton, the dramatic enhancement in the visible light photocatalytic performance of the AgI-N-TiO(2)-cotton could be attributed to the synergistic effect of AgI and N-TiO(2), including generation of visible light photocatalytic activity and the effective electron-hole separations at the interfaces of the two semiconductors. The photocatalytic activity of the AgI-N-TiO(2)-cotton was fully maintained upon several numbers of photodegradation cycles. In addition, according to the XRD patterns of the AgI-N-TiO(2)-cotton before and after reaction, AgI was stable in the composites under visible light irradiation. Moreover, a possible mechanism for the excellent and stable photocatalytic activity of AgI-N-TiO(2)-cotton under visible light irradiation was also proposed.     

Synthesis, characterization and photocatalytic evaluation of visible light activated C-doped TiO2 nanoparticles

We have demonstrated heterogeneous photocatalytic degradation of microcystin-LR (MC-LR) by visible light activated carbon doped TiO(2) (C-TiO(2)) nanoparticles, synthesized by a modified sol-gel route based on the self-assembly technique exploiting oleic acid as a pore directing agent and carbon source. The C-TiO(2) nanoparticles crystallize in anatase phase despite the low calcination temperature of 350 °C and exhibit a highly porous structure that can be optimized by tuning the concentration of the oleic acid surfactant. The carbon modified nanomaterials exhibited enhanced absorption in the broad visible light region together with an apparent red shift in the optical absorption edge by 0.5 eV (2.69 eV), compared to the 3.18 eV of reference anatase TiO(2). Carbon species were identified by x-ray photoelectron spectroscopy analysis through the formation of both Ti-C and C-O bonds, indicative of substitution of carbon for oxygen atoms and the formation of carbonates, respectively. Electron paramagnetic resonance spectroscopy revealed the formation of two carbon related paramagnetic centers in C-TiO(2), whose intensity was markedly enhanced under visible light illumination, pointing to the formation of localized states within the anatase band gap, following carbon doping. The photocatalytic activity of C-TiO(2) nanomaterials was evaluated for the degradation of MC-LR at pH 3.0 under visible light (λ > 420 nm) irradiation. The doped materials showed a higher MC-LR degradation rate than reference TiO(2), behavior that is attributed to the incorporation of carbon into the titania lattice.     

(N, F)-codoped TiO2 Nanocrystals as Visible Light-activated Photocatalyst

(N, F)-codoped anatase TiO2 nanocrystals with active visible light response were prepared by using a simple sol-gel approach. X-ray photoelectron spectroscopy measurements suggested that the substitutional N and F species replaced the lattice oxygen atoms in TiO2 nanocrystals. Such nanocrystals showed strong absorption from 400 to 550 nm, which was mainly induced by nitrogen doping. The phase transformation from anatase to rutile was hindered by fluorine doping at high calcination temperatures, which was verified by XRD patterns. The N2 adsorption-desorption isotherms revealed the absence of mesopores in these nanocrystals. The (N, F)-codoped TiO2 nanocrystals showed satisfying photocatalytic activity on the photo-degradation of methylene blue under visible light.     

CuAl2O4掺杂改性TiO2薄膜的制备与可见光催化性能研究

采用溶胶-凝胶方法在玻璃基片上制备了CuAl2O4掺杂改性的复合薄膜．研究了CuAl2O4的掺杂量、光照时间、薄膜厚度对TiO2复合薄膜光催化性能的影响，利用可见-紫外分光光度计测定酸性红B降解前后516nm处的吸光度，依此计算出薄膜对染料的降解率．借助于紫外可见光谱、X射线衍射、接触角测定仪等研究了薄膜的结构与性能．结果表明：随着CuAl2O4掺杂量的增加，TiO2复合薄膜对酸性红B水溶液的可见光降解脱色率增大．采用吸收光谱确定了CuAl2O4掺杂量为0％、0．5％、1％、1．5％％（摩尔分数）的TiO2复合薄膜的激发极限波长，分别是350、370、380、430nm，吸收边向可见区红移了20-80nm，可见光吸收范围明显扩大．     

Fabrication of TiO2/Ti electrode by laser-assisted anodic oxidation and its application on photoelectrocatalytic degradation of methylene blue

A TiO2/Ti mesh electrode by laser calcination was prepared in this article. The resulting TiO2 film was investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS), and it illuminated that the prepared electrode mainly consisted of anatase TiO2 nanoparticles on its surface and exhibited a superior photocatalytic activity. The photodegradation of methylene blue (MB) using the proposed electrode under different experimental conditions was investigated in terms of both UV absorbance at 664 nm and chemical oxygen demand (COD) removal. The electrical bias applied in photoelectrocatalytic (PEC) oxidation was also studied. The experimental results showed that under the optimal potential of +0.50 V (versus SCE), UV absorbance and COD removal during the photodegradation of MB by the proposed TiO2/Ti mesh electrode were 97.3% and 87.0%, respectively. Through the comparison between photocatalytic (PC) oxidation and photoelectrocatalytic (PEC) oxidation, it was found that PEC oxidation was a convenient and effective way to mineralize the organic matters and that laser-treated photoelectrode exceeded the oven-treated one.