载银TiO_2光催化剂的合成及活性研究

以钛酸四正丁酯为起始原料,采用溶胶-微波法合成出TiO2纳米粒子,借助XRD、UV-Vis吸收光谱等测试手段对其进行了表征,并以罗丹明B为模型污染物考察了酸水比、微波反应温度和微波反应时间等因素对样品光催化性能的影响。结果表明,溶胶-微波法制备TiO2的最佳工艺条件为:酸水比7:1,微波反应温度150℃,反应时间8min。以最佳工艺条件下制备的TiO2为原料,采用光还原法成功制备出载Ag纳米TiO(2摩尔比为1:1),将该光催化剂置于自然光下用于采油厂工业废水的处理,太阳光下照射10h,COD去除率达到92.35%。     

Ti-Zn催化剂合成及降解卷烟厂蒸叶废水的研究

采用溶胶-凝胶与水热相结合的方法合成了Ti-Zn复合催化剂,借助XRD、SEM、BET、UV-Vis等多种技术对其进行了表征,并将其用于卷烟厂蒸叶废水的光催化处理,考察了Ti-Zn比及投放量对催化剂光催化活性的影响规律。XRD分析表明,复合催化剂X射线衍射谱图中出现锐钛矿相TiO2的特征衍射峰,说明复合催化剂中的Ti以TiO2晶体形式存在,但谱图中并没有出现ZnO的特征衍射峰;UV-Vis吸收光谱表明,复合催化剂相比纳米TiO2其在紫外光区的吸收增强,即复合催化剂对光具有更高的利用率,但Ti-Zn比对复合催化剂吸收光谱影响不大。光催化实验表明,Ti-Zn复合催化剂的光催化活性明显高于纳米TiO2催化剂,且其光催化活性与Ti-Zn比及催化剂投放量有关,随着掺杂量及投放量的增加光催化活性均表现出了先增后降的变化趋势,当Ti-Zn比为10:1(摩尔比),投放量为1000mg/L左右时Ti-Zn复合催化剂对卷烟厂蒸叶废水表现出了较好的处理效果,废水COD去除率达到76.7%。     

微波干燥制备Ag/TiO2的光催化活性试验研究

利用钛酸丁酯溶胶—凝胶法制备TiO2凝胶,通过光化学沉积法在TiO2凝胶表面负载Ag,采用微波对凝胶进行干燥制备TiO2光催化剂。以甲基橙为模拟污染物进行光催化降解试验,结果表明该方法制备的Ag/TiO2催化剂光催化活性明显提高。     

钐离子掺杂二氧化钛光催化降解甲基橙研究

用溶胶-凝胶法制备了掺杂Sm^3＋的纳米TiO2,用XRD测定了其晶型,并以甲基橙为液相有机污染物实例研究了样品的先催化活性,发现Sm^3＋不能进入TiO2晶格中引起了TiO2晶格膨胀,而形成氧化物覆盖在其表面,Sm^3＋掺杂抑制了TiO2晶相的转变和粒径的增长。活性试验结果表明,Sm^3＋掺杂可提高TiO2的光催化活性,并且当掺杂摩尔分数为1．5％时,先催化活性最好。甲基橙的醌式结构比偶氮结构容易降解。     

铝片负载TiO2薄膜在降解甲基橙染料中的应用

以钛酸四正丁酯为原料,利用溶胶-凝胶法制备出能光催化降解甲基橙的铝片负载TiO2薄膜.催化活性评价结果表明,在500℃焙烧2小时得到的铝片负载TiO2薄膜具有最好的光催化降解甲基橙活性,同时该薄膜在反应介质中有很好的稳定性.XRD和SEM结果表明,TiO2薄膜由锐钛矿相组成,在焙烧后有均匀的龟裂,裂片大致为4 m×3 m.     

多壁碳纳米管的制备与可见光催化性能

采用溶胶-凝胶法,制备了多壁碳纳米管(MWCNTs)/CdS/TiO2复合半导体光催化剂。通过扫描电镜(SEM)、X射线衍射(XRD)和紫外-可见吸收光谱(UV-vis)等分析方法对光催化剂进行了结构表征,并考察了在可见光照射条件下MWCNTs/CdS/TiO2对甲基橙(MO)降解的光催化性能。结果表明,MWCNTs/CdS/TiO2能有效降解甲基橙。低浓度MO降解效果比高浓度好,光催化剂投加量为1.2 g/L即可达到较好的催化效果,酸性条件有利于光催化,投加适宜浓度的H2O(2低于10 mmol/L)时会和催化剂产生协同效果,浓度过大,催化效果下降。阴离子对催化效果有抑制作用,其中PO43-的抑制作用最强。所制备的复合催化剂具有较好的实际应用价值。     

磁性负载改良型纳米TiO_2的制备及光催化反应器的研发

采用自蔓延燃烧法、溶胶-凝胶、粉末-溶胶和共沉淀相结合的方法制备出了具有磁性的改良型纳米TiO2光催化剂,并用X射线衍射、SEM扫描电镜等方法进行表征;同时制备了一种可回收磁性负载易分离纳米TiO2的光催化反应器,并通过对甲基橙的光降解分析,对其光催化性能进行了评价。实验结果表明,该光催化反应器对有机废水的处理效果较好,而且结构简单,建造方便,有着广泛的应用前景。     

高度有序的TiO2纳米管阵列光催化性能研究

采用恒压阳极氧化法在纯钛箔表面制备TiO2纳米管阵列,利用SEM和XRD对其进行了形貌和晶型的分析和表征,并通过TiO2纳米管阵列膜对甲基橙光催化降解,探讨光照时间、甲基橙溶液的初始浓度、溶液的初始pH值和H2O2加入浓度等因素对甲基橙的脱色率影响.结果表明,H2O2加入浓度为50mg·L-1,紫外光照射2h,溶液为中性时,在30 mg·L-1的甲基橙溶液(50mL)中,甲基橙溶液的脱色率达到100%.当H2O2加入浓度进一步增大到100 mg·L-1时,光催化的效率进一步提高,紫外光照射1h,甲基橙溶液的脱色率就已经达到了100%,并未出现抑制光催化的现象.同时还研究了TiO2纳米管阵列电极的稳定性.实验结果表明,随着TiO2纳米管阵列使用次数的增加,其光催化效果略有所下降.     

乙二胺溶胶凝胶法氮掺杂TiO_2的光催化研究

以钛酸四丁酯(TBT),乙二胺(EDA)为前驱体,乙醇为溶剂,冰醋酸为抑制剂,采用溶胶-凝胶法制备了N掺杂纳米TiO2光催化剂。通过紫外-可见吸收光谱(UV-Vis)、荧光发射光谱(FES)、X射线衍射光谱(XRD)、X射线光电子能谱(XPS)、和BET比表面分析对其光谱特征、晶相结构、表面组成、比表面积进行了表征,以苯酚为模拟污染物考察了其光催化活性。结果表明:该方法制备的N掺杂纳米TiO2的光谱吸收带发生了明显红移,当EDA/TBT(摩尔比)=1/10及焙烧温度为550℃时,所制备样品对可见光的吸收最强,可见光照射150min苯酚的降解率为34.6%,紫外光照射100min苯酚的降解率达到97.8%。     

溶胶-凝胶法制备TiO2薄膜及其光催化性能的研究

通过溶胶-凝胶法制得溶胶-凝胶溶液，采用浸渍-提拉法制备纳米二氧化钛薄膜，制得的薄膜在500℃热处理1h。用X-射线衍射仪测定TiO2的纳米薄膜的物相组成，经图峰鉴定证明TiO2为锐钛矿型。用扫描电镜观察薄膜的表面形貌，发现其表面均匀分布着颗粒直径为20nm左右的TiO2球形颗粒。用制得的薄膜对铬黑T水溶液和甲基橙水溶液进行光催化，实验结果表明，制得的二氧化钛薄膜有较高的光催化活性。     

Effect of Sb dopant amount on the structure and electrocatalytic capability of Ti/Sb-SnO2 electrodes in the oxidation of 4-chlorophenol

Ti/Sb-SnO_2 anodes were prepared by thermal decomposition to examine the influence',of the amount of Sb dopant on the structure and electrocatalytic capability of the electrodes in the oxidation of 4-chlorophenol.The physicochemical properties of the Sb-SnO_2 coating were markedly influenced by different amounts of Sb dopant.The electrodes,which contained 5% Sb dopant in the coating, presented a much more homogenous surface and much smaller mud-cracks,compared with Ti/Sb-SnO_2 electrodes containing 10% or 15% Sb dopant,which exibited larger mud cracks and pores on the surface.However,the main microstructure remained unchanged with the addition of the Sb dopant.No new crystal phase was observed by X-ray diffraction(XRD).The electrochemical oxidation of 4-chlorophenol on the Ti/SnO_2 electrode with 5% Sb dopant was inclined to electrochemical combustion;while for those containing more Sb dopant,intermediate species were accumulated.The electrodes with 5% Sb dopant showed the highest efficiency in the bulk electrolysis of 4-chlorophenol at a current density of 20 mA/cm~2 for 180 min;and the removal rates of 4-chlorophenol and COD were 51.0% and 48.9%,respectively.     

Preparation, characterization, and photocatalytic activities of boron- and cerium-codoped TiO2

Boron- and cerium-codoped TiO2 photocatalysts were synthesized using modified sol-gel reaction process and characterized by X- ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, particle size distribution （PSD）, diffuse reflectance spectra （DRS）, and Brunauer-Emmett-Teller （BET）. The photocatalytic activities were evaluated by monitoring the degradation of dye Acid Red B （ARB）. The results showed that the prepared photocatalysts were mixed oxides mainly consisting of titania, ceria, and boron oxide. The structure of TiO2 could be transformed from amorphous to anatase and then to rutile by increasing calcination temperature; the transformation being accompanied by the growth of particle size without any obvious change in phase structure of CeO2. The XPS of B1.6Ce1.0-TiO2 prepared at 500℃ showed that a few boron atoms were incorporated into titania and ceria lattice, whereas others existed as B2O3. Cerium ions existed in two states, Ce^3＋ and Ce^4＋, and the atomic ratio of Ce^3＋/Ce^4＋ was 1.86. When boron and cerium were doped, the UV-Vis adsorption band wavelength showed an obvious shift toward the visible range （〈526 nm）. As the atomic ratio of Ce/Ti increased to 1.0, the absorbance edge wavelength increased to 481 nm. The absorbance edge wavelength decreased for higher cerium doping levels （Ce/Ti=2.0）. The particles size ranged from 122 to 255 nm with a domain at 168 nm （39.4%）. The degradation of ARB dye indicated that the photocatalytic activities of boron- and cerium-codoped TiO2 were much higher than those of P25 （a standard TiO2 powder）. The activities increased as the boron doping increased, whereas decreased when the Ce/Ti atomic ratio was greater than 0.5. The optimum atomic ratio of B/Ti and Ce/Ti was 1.6 and 0.5, respectively.     

锆英石基An4+放射性核素固化体性能研究

为研究锆英石基An4+(四价锕系核素)放射性核素固化体的性能,利用Ce4+作为An4+的模拟替代物质,以ZrO2、SiO2和CeO2粉体为原料,采用高温固相法制备出包容20%(物质的量,下同)Ce4+的锆英石基固化体,利用60Co源γ射线辐照装置对其进行572.1kGy的γ射线辐照.利用粉末X射线衍射仪、扫描电子显微镜和电感耦合等离子体质谱仪对γ射线辐照前后固化体的物相、结构、微观形貌及模拟核素的浸出行为进行了研究.结果表明,固化体中虽包容有20%的Ce4+,但其主物相仍以锆英石物相为主,与标准样品相比晶胞参数发生10-4nm量级的变化,经γ射线辐照后样品晶胞参数仅发生了10-5~10-4nm量级的微弱变化,在pH6.5的HCI浸出液中Ce4+的平衡浓度低于0.30μg/L.     

Photocatalytic degradation of 4-chlorophenol under P-modified TiO2/UV system:Kinetics, intermediates, phytotoxicity and acute toxicity

A series of phosphorus-modified titanium dioxide samples with varying P/Ti atomic ratio were conveniently prepared via a conventional solgel route. The effects of phosphorus content and calcination temperature on the crystalline structure, grain growth, surface area, and the photocatalytic activity of P-modified TiO₂ were investigated. The XRD results showed that P species slow down the particle growth of anatase and increase the anatase-to-rutile phase transformation temperature to more than 900℃. Kinetic studies on the P-modified TiO₂ to degraded 4-chlorophenol had found that the TP5₅₀₀ prepared by adopting a P/Ti atomic ratio equal to 0.05 and calcined at 500℃ had an apparent rate constant equal to 0.0075 min^-1, which is superior to the performance of a commercial photocatalyst Degussa P25 K_app = 0.0045 min^-1 and of unmodified TiO₂ (TP0₅₀₀) K_app = 0.0022 min^-1. From HPLC analyses, various hydroxylated intermediates formed during oxidation had been identified, including hydroquinone (HQ), benzoquinone (BQ) and (4CC) 4-chlorocatechol as main products. Phytotoxicity was assessed before and after irradiation against seed germination of tomato (Lycopersicon esculentum) whereas acute toxicity was assessed by using Folsomia candida as the test organism. Intermediates products were all less toxic than 4-chlorophenol and a significant removal of the overall toxicity was accomplished     

Composition and crystal structure of N doped TiO2 film deposited at different O2 flow rate by direct current sputtering

N doped Ti0₂ films were deposited by direct current pulse magnetron sputtering system at room temperature. The influence of 0₂ flow rate on the crystal structure of deposited films was studied by Stylus profilometer, X-ray photoelectron spectroscopy, and X-ray diffractometer. The results indicate that the 0₂ flow rate strongly controls the growth behavior and crystal structure of N doped Ti0₂ film. It is found that N element mainly exists as substitutional doped state and the chemical stiochiometry is near to TiO_1.68±0.06N_0.11±0.01 for all film samples. N doped Ti0₂ film deposited with 2 sccm (standard-state cubic centimeter per minute) 0₂ flow rate is amorphous structure with high growth rate, which contains both anatase phase and rutile phase crystal nucleuses. In this case, the film displays the mix-phase of anatase and rutile after annealing treatment. While N doped Ti0₂ film deposited with 12 cm³/min 0₂ flow rate displays anatase phase before and after annealing treatment. And it should be noticed that no TiN phase appears for all samples before and after annealing treatment.     

由天然钠基膨润土直接合成钛柱撑膨润土的研究

以高庙子天然钠基膨润土为原料,钛酸正丁酯在pH=2~5环境下水解聚合成柱撑剂,水热法制备了钛柱撑膨润土(Ti-pillaredclay,Ti-PILC)。采用X-射线粉晶衍射(XRD)、扫描电镜(SEM)、比表面积分析仪(BET)分析了产物的结构和形貌。探讨了制备Ti-PILC的工艺参数对结构的影响。结果表明:Ti-PILC呈片层桥结的多孔结构;钛柱撑剂撑开的d001层间距为1.860 8~2.481 3 nm;比表面积由31 m2/g增加到191 m2/g。柱撑最佳工艺参数为:钛/土比30 mmol/g,反应时间为3 h,反应温度为100℃。     

Visible light responsive N-F-codoped TiO2 photocatalysts for the degradation of 4-chlorophenol

Visible light responsive N-F-codoped TiO₂ photocatalysts exhibit a higher catalytic activity than N-doped TiO₂ for the degradation of 4-chlorophenol due to the synergistic effect of nonmetal elements.     

载钛活性炭电极电吸附除盐性能的研究

采用sol-gel法制备载钛活性炭(Ti-AC),并用此活性炭制取了Ti-AC电极,利用扫描电子显微镜(SEM)、X射线荧光光谱(XRF)、X射线衍射仪(XRD)和电化学工作站等对活性炭电极的表面形貌、元素组成、化合物形态以及电极的电化学性能进行分析,并考察载钛前后活性炭电极的除盐能力,而且对Ti-AC电极与碳纳米管电极和活性炭纤维电极的实用性进行比较.结果表明,Ti-AC电极含有一定量的Ti元素,其形态为金红石型TiO2,并在电极表面积聚为很多的絮状结构,载钛后双电层形成速率更快,电吸附容量显著提高.对NaCl的吸附试验表明,Ti-AC电极物理吸附降低,电吸附明显提高,除盐率提高了62.7%.实用性分析表明,Ti-AC电极更适宜应用于电吸附除盐.     

纳米TiO_2包覆微米Cr_2O_3粒子的制备及表征研究

目的研究室温条件下纳米TiO_2包覆微米Cr_2O_3粒子的物相、显微组织及其光催化活性。方法采用钛酸丁酯为原料,通过酸催化的胶溶-沉淀法制备纳米TiO_2包覆微米Cr_2O_3复合粒子,利用SEM,XPS,XRD,Raman及紫外-可见漫反射光谱等手段对复合粒子进行表征。结果 XPS分析表明,微米Cr_2O_3粒子的表面存在C,O,Ti,Sn,Cr等元素。场发射扫描电镜观察表明,粒径大小为10~15 nm左右的TiO_2颗粒包覆在Cr_2O_3微粒表面,从而形成纳米/微米复合结构。Raman光谱结果显示,空载实验获得的TiO_2颗粒样品呈现锐钛矿型。UV-Vis光谱分析表明,负载Cr_2O_3微粒后使半导体的吸收峰值明显红移,在370,460,600 nm处出现了3个吸收峰,最大吸收波长达到750 nm左右。结论锐钛矿相TiO_2成功包覆在微米Cr_2O_3粒子表面,扩展了复合半导体的光响应范围,有望实现可见光催化活性。     

制备参数对Mn-Ce/TiO2催化剂脱硝性能的影响

以锐钛矿型TiO₂为载体,采用分步共混法制备了Mn-Ce/TiO₂催化剂,通过考察不同活性组分前驱体、焙烧温度以及活性组分负载量对催化剂样品脱硝性能的影响,以确定最佳制备参数;结合XRD（X射线衍射）、XPS（X射线光电子能谱分析）、BET比表积等表征手段研究制备参数对催化剂性能的影响.结果表明:无定型态MnO₂含量越多,越有利于提高催化剂的脱硝活性;催化剂样品表面原子浓度比Mn/Ti[或（Mn+Ce）/Ti]越高,催化剂表面有效活性组分越多,催化剂脱硝活性越好.以自制Mn盐（MX）为前驱体,在Mn-Ce活性组分负载量为16%时,经500℃焙烧的催化剂样品脱硝活性最高;反应空速为10000 h-1,反应温度为80℃时,其脱硝效率可达80%,150℃时脱硝效效率可达99%.