Preparation and characterization of in-site regenerated TiO_2-ACFs photocatalyst

In-site regenerated titanium dioxide-activated carbon fibers (TiO2-ACFs) photocatalyst was prepared by the sol-gel method. De-tailed surface and structural characterization of the TiO2-ACFs photocatalyst was carried out. The photoactivity of TiO2-ACFs under ultra-violet irradiation was compared with original ACFs and pure TiO2 by the degradation of methylene blue aqueous solution. The degradation efficiency by the TiO2 (5wt%)-ACFs sample is much higher than that by TiO2 and ACFs. The results show that the p...     

负载TiO_2光催化剂的制备表征及其降解效果

为解决传统纳米光催化剂不易分离和一般载体的比表面积较小、悬浮性差的问题,将纳米TiO2负载在不耐高温的聚丙烯多面球上,用偶联剂法制备了负载型TiO2光催化剂,并与溶胶-凝胶法制备的负载型TiO2光催化剂降解酸性红B染料溶液的效果进行比较,利用XRD和N2吸附法表征了催化剂表面结构性质.结果表明,偶联剂法制备的TiO2薄膜晶相单一,均为纳米锐钛矿,其晶粒度较小,比溶胶凝胶法制备的TiO2薄膜光催化活性高,降解效果优于溶胶-凝胶法.试验钛酸酯偶联剂用乙醇溶剂按体积比1∶1进行稀释,最佳TiO2投加质量比为2.5%~5%,且随着光照强度的增加,光催化反应速率提高.发现光催化氧化法处理酸性红B溶液的效果优于直接光解法;在连续使用7次以后,负载TiO2光催化剂的活性基本不变,可重复使用.     

常温常压气-固光催化CO2加氢合成一碳化合物的研究

大气中ＣＯ２含量的增加是导致最严重环境污染－－温室效应的主要原因,因此,人们对ＣＯ２的固定及利用越来越重视,目前对水溶液悬浮体系光催化还原ＣＯ２研究得比较多,气－固光催化体系中,常温常压下合成ＣＯ２＋Ｈ２为有机物少有报道。通过对几种ＴｉＯ２型催化剂在悬浮体光催化体系中ＣＯ２催化活性的比较,选择了活性较高的Ｐｄ／ＲｕＯ２／ＴｉＯ２催化剂,采用原位红外的实验方法对ＣＯ２加氢反应及其产物进行了研究,结果     

钇掺杂TiO2形态结构表征及光催化活性研究

以溶胶一凝胶法制备了钇（Y）掺杂的TiO2,采用SEM、EDS、BET、XRD等测试手段对其进行了表征．XRD分析结果表明钇掺杂的TiO2具有锐钛矿型结构;SEM观察发现该催化剂表面有大量孔,平均粒径为10～20nm;EDS测试表明Y在TiO2中分布均匀;BET测试结果表明掺杂钇后,催化剂比表面积由原来的49．03m^2／g增加到99．43m^2／g;通过对甲基橙的光催化降解测试证明Y掺杂的TiO2的催化效率比纯TiO2有很大提高,90min时降解率达到85％,比纯TiO2降解效率提高40％．实验还表明Y掺杂的TiO2对可见光的响应活性比纯TiO2有一定提高．     

MoP/TiO_2-SiO_2-Al_2O_3的制备及加氢脱芳性能研究

采用溶胶—凝胶法及共浸渍法制备了TiO2-SiO2-Al2O3复合载体,并用共浸渍法制备负载型MoP/TiO2-SiO2-Al2O3催化剂。XRD结果表明,TiO2的晶相衍射峰呈锐钛矿,SiO2则大多以无定型态分散于γ-Al2O3晶体表面。通过原位还原技术对催化剂进行还原处理,在连续固定床反应器上进行活性评价,结果表明,钛硅铝物质的量比对催化剂的活性有很大的影响,在温度为360℃,压力为3MPa,液时空速为1h-1,氢油体积比为500∶1的反应条件下,n（Ti）∶n（Si）∶n（Al）为1∶1∶4,Mo负载量为20%时,MoP/TiO2-SiO2-Al2O3催化剂的加氢脱芳活性最高,达到65.6%。并且TiO2-SiO2-Al2O3三元复合载体比传统的γ-Al2O3和SiO2-Al2O3二元复合载体的活性分别提高了19.6%和13.6%。     

p-n异质结TiO_2/NiO光催化剂的制备及其性能研究

采用溶胶凝胶和浸渍煅烧相结合的方法,制备出了具有p-n异质结结构的球形二氧化钛表面负载氧化镍颗粒的复合光催化剂.利用XRD、TEM、UV-Vis和PL等方法对催化剂的晶相组成、微观结构、吸光性能和光致发光性能等进行了表征.结果表明氧化镍晶粒与二氧化钛晶粒紧密接触形成p-n异质结.氧化镍颗粒的负载使复合光催化剂的吸收带边发生了明显的红移,并进入了可见光区.形成的p-n异质结促进了二氧化钛光生电子和空穴的分离,从而降低了其本征发光光强度.通过在可见光条件下对亚甲基蓝的降解研究了其光催化性能,结果表明,氧化镍颗粒的负载使二氧化钛的光催化效果在可见光区有了显著地提高,并在一定范围内随着氧化镍含量的增加光催化效果也随之提高.     

Fe掺杂改性TiO_2光催化膜的性能

二氧化钛是一种具有半导体性质的光催化剂,可利用低能量的紫外光照射,进行有机污染物光催化的分解反应。用溶胶凝胶法合成Ti O2,并在其中掺杂Fe3+。在玻璃片上制备了Ti O2薄膜,并用此薄膜对甲基橙在紫外光和可见光下进行降解。发现经过掺杂的薄膜在450℃处理后,不会对Ti O2结构产生明显的影响,但可大大提高Ti O2在紫外光照射下对污染物的分解效率,并且大大拓展了Ti O2对可见光的响应范围。     

金红石TiO_2-CNTs粉体的制备及光催化性能

利用微波等离子体技术,对钛铁矿进行了还原并获得金红石型TiO2-CNTs复合粉体.通过XRD和SEM分析了不同制备条件对产物的影响,研究了不同条件下制备的复合粉体对甲基橙光降解效率.结果表明,该方法制备出的复合粉体在可见光和紫外光下都具有较强的光催化效果,纳米碳管的结构和含量对光催化效率有较强的影响.     

纳米TiO2的溶胶—凝胶法制备及其表征

以钛酸正丁酯(TNB)-去离子水-盐酸-乙酰丙酮(Acac)的乙醇溶液为反应体系,采用溶胶—凝胶法制备纳米TiO2溶胶颗粒。通过DLS、XRD和HRTEM等表征手段对TiO2颗粒的生成过程、其粒径和晶型的调控等方面进行研究。发现低温环境下TiO2的生成主要经历水解反应形成螯合物、缩合反应生成TiO2溶胶、TiO2溶胶颗粒融合这三个阶段。并且通过调节反应温度和催化剂浓度,可在无需高温锻烧的情况下,制得具有典型锐钛矿晶型的高分散性TiO2溶胶颗粒。     

Comparative study on photocatalytic properties of TiO2 nanoparticles prepared in acidic medium and basic medium by hydrothermal method

In order to investigate the difference of phtotocatalytic properties of TiO2 samples prepared in different pH conditions,TiO2 nanoparticles were prepared in acidic medium and basic medium by a hydrothermal process,respectively.The samples were characterized using XRD,TEM,BET,XPS,surface photovoltage spectroscopy (SPS) and field-induced surface photovoltage spectroscopy (FISPS).Effects of temperature and pH in the hydrothermal process on particle sizes,specific surface areas,and photocatalytic properties of the TiO2 nanocrystalline were investigated.The experimental results indicate that the photocatalysis activity of TiO2 nanoparticles prepared in basic medium (B-TiO2) is superior to that in acidic medium (A-TiO2),which is ascribed to the difference of surface state between A-TiO2 and B-TiO2.     

Preparation and photocatalytic activity of Cu^2＋-doped TiO2/SiO2

Cu2+-doped nanostructured TiO2-coated SiO2. (TiO2./SiO2) particles were prepared by the layer-by-layer assembly technique and their photocatalytic property was studied. TiO2 colloids were synthesized by the sol-gel method using TiOSO4 as a precursor. The experimental results showed that TiO2 nanopowders on the surface of SiO2 particles were well distributed and compact. The amount of TiO2 increased with the increase in coating layers. The shell structure appeared to be composed of anatase titania nanocrystals at 550℃. The 2-layer coated TiO2 particles on the surface showed a higher degradation rate compared with all the dif-ferent-layer samples. The photocatalytic activity of Cu2+-doped TiO2/SiO2 was higher than that of undoped TiO2/SiO2. The optimum dopant content was about 0.10wt%.     

碳纳米管负载TiO_2光催化剂制备与活性研究

采用表面溶胶-凝胶法制备碳纳米管负载TiO2光催化剂,通过改变负载次数制备不同TiO2负载量的光催化剂.采用XRD,SEM,BET以及TG-DSC对该催化剂进行了表征.采用结晶紫光催化降解,研究碳纳米管负载二氧化钛的光催化活性.光催化测试结果表明,该碳纳米管负载TiO2光催化剂在紫外光照射下具有比TiO2(P25)光催化剂更优越的光催化降解结晶紫的活性.     

H3PW12O40-TiO2/膨润土光催化降解甲基橙的催化性能

通过溶胶凝胶制得H3PW12O40-Ti（OH）4凝胶,并柱撑于膨润土层间制备了复合光催化剂H3PW12O40-TiO2/膨润土。由XRD、SEM、EDS对制备的复合光催化剂进行表征测试表明,固载的H3PW12O40-TiO2使膨润土层状结构发生明显变化,柱撑体H3PW12O40-TiO2呈弥散状态,且TiO2为锐钛结构,催化剂为颗粒粒径大小不一、分布松散的复合材料。对甲基橙的H3PW12O40-TiO2/膨润土光催化降解应用表明,掺杂的杂多酸使所制备的复合催化剂光催化活性得到了极大提高,在光催化体系下有较广的pH适应范围,且制备的催化剂具有良好的催化稳定性。在表征分析及应用实验的基础上,提出了H3PW12O40-TiO2/膨润土的强化催化作用原理。     

固体超强酸SO_4~(2-)/TiO_2的制备及其在季戊四醇酯化反应中的催化性能

采用溶胶-凝胶法制备SO42-/TiO2固体超强酸,以异辛酸与季戊四醇的酯化反应为探针反应,考察浸渍液种类及浓度、焙烧温度对固体超强酸催化性能的影响。用流动指示剂法测定催化剂的酸强度,并采用原位吡啶吸附的IR谱图对催化剂进行表征。结果表明,在H2SO4浸渍液浓度为1.0 mol.L-1、500℃下焙烧3 h制备的SO42-/TiO2催化剂活性最好,酯化率可达到85.0%。     

The Effect of SiO_2 Additive on Super-hydrophilic Property of TiO_2-SiO_2 Thin Film by Sol-gel Method

TiO2-SiO2 thin films have been prepared on slide glass substrates by sol-gel method, and the effect of SiO2 additive on photo-generated hydrophilicity of TiO2 thin film was investigated by measuring the contact angle of water, the microstructure, the transmittance, the photocatalytic activity and the specific surface area . The results showed that 10mol% of SiO2 additive was the most effective for decreasing contact angle of water. The SiO2 additive of less than 30mol% has a suppressive effect on the crystal growth of anatase in calcinations, resulting in a large surface area. Consequently, the super-hydrophilicity was improved.     

The Effect of SiO2 Additive on Super-hydrophilic Property of TiO2-SiO2

TiO2-SiO2 thin films have been prepared on slide glass substratesby sol-gel method, and the effect of SiO2 additive on photo-generated hydrophilicity of TiO2 thin film was investigated by measuring the contact angle of water, the microstructure, the transmittance, the photocatalytic activity and the specific surface area. The results showed that 10mol% of SiO2 additive was the most effective for decreasing contact angle of water. The SiO2 additive of less than 30mol% has a suppressive effect on the crystal growth of anatase in calcinations, resulting in a large surface area. Consequently, the super-hydrophilicity was improved.     

Photocatalytic oxidation of Rhodamine B in a three-phase internal circulating fluidized bed with TiO2/SiO2 as photocatalyst

A novel photoreactor of three-phase internal circulating fluidized bed was applied to the degradation of Rhodamine B with TiO2/SiO2 catalyst and TiO2 powder,respectively.The experimental results showed that the photocatalytic activity of TiO2/SiO2 catalyst was much higher than that of TiO2 powder under the same condition,and the half life of Rhodamine B using TiO2/SiO2 was 9.5 min,much lower than 63 min when using TiO2 powder.Moreover,TiO2/SiO2 had a good adsorption capacity of Rhodamine B,which played an important role on degradation.In addition,it was found that the degradation kinetics of Rodamine B with TiO2/SiO2 catalyst did not follow the first order reaction.The degradation kinetics model in terms of the adsorption process of catalyst and the analytic solution of reactant degradation rate in liquid phase could be deduced,which consisted of two parts.The first part was due to the adsorption,while the second part was due to the photocatalysis.In the beginning of the reaction,the adsorption process was dominant.However,when the adsorption achieved a balance,the degradation of Rhodamine B in liquid phase and solid phase was mainly caused by photocatalysis and the degradation kinetics model conformed to the first order reaction.     

TiO2三相内循环流化床光催化反应体系的研究

提出基于负载型光催化剂的三相内循环流化床光催化氧化反应装置，实现了光、固体催化剂和溶液的大面积有效接触，提高了传质效率。采用溶胶－凝胶法筛选出以粗孔硅胶为载体的适合于该反应体系的负载型TiO2催化剂。利用10mg/L罗丹明B溶液检验了反应体系的光催化氧化性能，在以20W紫外灯为光源的情况下，50g光催化剂处理500mL溶液3h的去除率达到了85％。     

纳米二氧化钛光催化薄膜的研制

采用溶胶-凝胶法(Sol-gel)制备了二氧化钛光催化薄膜，利用原子力显微镜(AFM)对薄膜表面结构进行观测．薄膜中二氧化钛粒子以纳米级分布，薄膜均匀、连续无龟裂．分别测试了纳米二氧化钛薄膜和普通二氧化钛颗粒在紫外灯照射下对CHCl3的催化降解速率．实验分析结果表明具有表面效应，量子尺寸效应的纳米二氧化钛薄膜有着更高的光催化活性和降解速率．     

陶粒负载纳米TiO2光催化降解水中腐殖酸

采用溶胶-凝胶法制备了以陶粒为载体的新型、高光催化活性的复合光催化剂TiO2/陶粒,使用XRD、TG-DTA、FT-IR进行表征;以腐殖酸为目标降解物,探讨了光催化氧化降解腐殖酸的规律,考察了催化剂投加量、腐殖酸溶液初始浓度、初始pH值、光强、反应时间、焙烧温度等因素对腐殖酸去除效果的影响.结果表明,在700℃温度下焙烧的催化剂具有最大光催化活性;腐殖酸的去除率随腐殖酸初始浓度和pH值的降低而增大;催化剂经重复使用几次后,仍具有较高的光催化性能.