高可见光响应型单斜介孔BiVO4的合成与表征

利用纳米铸造法,以立方有序介孔分子筛MCM-48为硬模板,550℃成功制备了结晶良好的纯相单斜介孔BiVO4.采用XRD、TEM、BET及UV-Vis光谱分析对样品的结构进行了表征,结果表明:与水热法制备的大颗粒样品相比,"纳米铸造"介孔BiVO4的平均孔径为16.8nm,孔体积为0.1 cm2/g,比表面积高达22.9 m2/g,有效减少了光生电子和空穴复合的几率,在可见光范围内表现出优良的可见光催化活性,90min内对乙基黄原酸钾的光催化降解率高达78%.     

介孔SiO2负载和包覆的纳米金属颗粒的制备与研究

制备了以SiO2为核、介孔SiO2为壳的核-壳颗粒负载纳米金属颗粒以及介孔SiO2壳层包覆SiO2负载的纳米金属颗粒。结果表明,十六烷基三甲基溴化胺(CTAB)作为模板剂,有助于介孔SiO2壳层包覆SiO2核的结构形成,介孔SiO2壳层的孔径方向垂直于SiO2核的表面;在聚乙烯吡咯烷酮(PVP)的稳定作用下,Pt纳米颗粒能均匀地分布在介孔SiO2壳层的表面。单分散SiO2颗粒经过3-氨丙基三乙氧基硅烷(APS)功能化后,可负载纳米金属颗粒。进一步研究表明,以SiO2负载纳米金属颗粒为核,NH3.H2O,乙醇和水为分散剂,CTAB为模板剂,正硅酸乙酯(TEOS)为硅源,还能制备介孔SiO2壳包覆SiO2负载的纳米金属颗粒,而且介孔SiO2壳层的厚度可通过TEOS的含量调节。     

负载型SrTiO_3/HZSM-5光催化材料制备与性能研究

采用溶胶-凝胶法制备HZSM-5负载SrTiO_3,对其进行XRD,SEM,BET,BJH和FT-IR表征,研究SrTiO_3/HZSM-5光催化降解活性艳红X-3B的活性。结果表明:SrTiO_3材料的主要成分为钙钛矿结构SrTiO_3,并含有少量SrCO3相。在负载型χSrTiO_3/HZSM-5样品中,SrTiO_3包覆在HZSM-5的外表面。负载型催化剂的比表面积主要由分子筛提供,材料中的孔径主要分布在2~20nm范围内。负载后SrTiO_3的光催化活性明显提高,30%SrTiO_3/HZSM-5具有最强的光催化活性。经90min光照后,93.8%的活性艳红X-3B在30%SrTiO_3/HZSM-5上降解,而在纯SrTiO_3上只能降解23.9%。     

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。     

CuMnO2/TiO2复合光催化剂增效催化降解亚甲基蓝

首次利用旋涂法将CuMnO_2纳米晶负载于TiO_2纳米棒阵列薄膜上,制备出光催化性能增强的CuMnO_2/TiO_2复合光催化剂,并考察了样品对亚甲基蓝(MB)的光催化降解性能。研究结果表明,CuMnO_2纳米晶和TiO_2纳米棒之间形成p-n异质结结构,能够有效促进电子和空穴的分离,使得CuMnO_2/TiO_2复合光催化剂具有更高的光催化性能。采用浓度为0.25 g/L的CuMnO_2悬浮液制得的CuMnO_2/TiO_2复合材料的光催化降解效率最高,其光催化效率和表观速率分别为88%和0.298 6 h~(-1),较纯TiO_2提高约26%和80%。     

纳米光催化剂Sm2InNbO7的制备及其可见光产氢活性

采用溶胶-凝胶法制备了纳米光催化剂Sm2InNbO7,通过XRD、FE-SEM、BET以及UV-Vis DRS测试对该材料的结构、粒径、比表面积和光吸收性能进行了表征。结果表明,Sm2InNbO7的晶粒尺寸和比表面积与柠檬酸(CA)加入量和煅烧温度有关。着重考察了不同条件下制备的Sm2InNbO7系列催化剂的光催化分解水产氢活性。实验结果表明,当CA与金属阳离子(Nb5++Sm3++In3+)的物质的量的比为2、煅烧温度为1073K时,获得的Sm2InNbO7纳米粉体具有最高的光催化产氢活性,测得的8h内平均产氢速率为8.32μmol/h,为固相法制备的Sm2InNbO7粉体的产氢速率的2.2倍。     

Pt掺杂介孔TiO_2/导电碳毡光电极的制备及光电催化性能

以四氯化钛为钛源、十六烷基三甲基溴化铵为模板剂、氯铂酸为掺杂离子、导电碳毡为载体,通过水热合成法制得液晶-Pt离子-无机物钛前驱体溶液,在超声波辅助下采用浸渍提拉法进行负载,在氮气保护下焙烧得到导电碳毡负载铂掺杂介孔TiO_2(TiO_2-Pt/CCF)光电极,利用现代表征手段对材料结构进行表征。以苯甲醛为目标降解物,对材料的光电催化活性进行研究,并分析了光电协同机制。结果表明:介孔化处理提高了TiO_2-Pt/CCF的比表面积,增大了降解反应的有效面积和催化剂表面降解物浓度;金属离子掺杂引入了杂质能级,减小了TiO_2的能带隙,同时,Pt充当着光生电子-空穴捕获阱,阻止电子-空穴对的复合,提高了TiO_2-Pt/CCF的光电催化效率;TiO_2固载化提高了对目标降解物的吸附和表面电子转移。在多功能的协同改性下,TiO_2-Pt/CCF比无孔TiO_2/CCF和介孔TiO_2/CCF有更高的催化活性。     

纳米CeO2/TiO2介孔复合体系的合成与表征

采用结构导向-超临界流体干燥(SCFD)-浸泡沉淀法制备了CeO2／TiO2介孔组装纳米复合粉体，通过TEM，XRD,BJH和BET等技术对获得的粉体进行了表征，并将其应用于光催化降解3B艳红染料和干电流变体中．结果表明，将稀土粒子CeO2组装到介孔TiO2的纳米孔道中形成的复合体系的光催化、光吸收和介电特性不同于纳米TiO2颗粒，表现出了明显的增强效应．     

N-CQDs修饰介孔TiO2/RGO异构体的构建及光催化性能研究

以柠檬酸三铵为前驱体,构建了系列N-CQDs(N掺杂碳量子点)修饰介孔TiO_2/RGO(还原氧化石墨烯)异构体,并通过XRD、TEM、BET、BJH、XPS、PL、UV-Vis等测试手段系统表征其样品的微观结构以及谱学性能,通过使用模拟太阳光为光源测试其光催化性能。实验可知,所构建系列样品均为锐钛矿相TiO_2晶体结构,且显著形成了H2型介孔结构,均属于langmuir Ⅳ型孔径结构;柠檬酸三铵的引入以及RGO的异构化逐步地增加介孔TiO_2光催化体系比表面积,体系比表面积最高可达331.6 m~2/g;N-CQDs的修饰以及RGO的异构化,使介孔TiO_2光催化体系光生电子效率逐步地提升,同时体系光谱响应范围逐步地拓宽;所构建介孔TiO_2异构体均具有较强的可见光光催化性能,其中样品N-CQDs-MT/RGO-1.8的光催化活性最强,在模拟太阳光照射下,对甲基橙的降解率在10 min内可达到90%左右,1 h的降解率可达到99%。     

CuO/TiO_2异质多孔纳米结构的制备及其光催化性能

以Cu(OH)_2纳米棒阵列为前驱体,钛酸四丁酯为钛源,采用外向包覆合成法,利用Cu(OH)_2自身热分解产生的微量水分子与负载在其表面的钛酸四丁酯缓慢反应,制备了CuO/TiO_2异质多孔纳米结构,并研究了产物对罗丹明B(RhB)的光催化降解性能。结果表明,得到的产物薄膜为直径2~4μm的微孔组成的多孔纳米结构,微孔的孔壁由直径500nm左右的纳米棒组装而成。产物CuO/TiO_2异质多孔纳米结构比纯TiO_2纳米结构对RhB有更好的光催化降解性能,这主要是由两方面的原因引起的:一方面,CuO/TiO_2异质多孔纳米结构具有更好的吸附性能和更大的比表面积;另一方面,产物CuO/TiO_2为异质复合纳米结构,异质结的存在能有效地降低光生电子空穴对的复合,从而提高产物的光催化降解效果。     

Mesoporous TiO2 thin films embedded with Au nanoparticles for the enhancement of the photocatalytic properties

Mesoporous TiO₂ thin films were prepared by hydrothermal-oxidation of titanium metal thin films, which were obtained by DC magnetron sputtering technique. Gold nanoparticles, which were prepared by reduction of HAuCl₄, were embedded into the holes of the mesoporous TiO₂ films by capillary method followed by annealing in air up to 400 °C. The size of pore of TiO₂ films is about 100 nm and that of Au nanoparticles is about 10 nm in average. The morphology of the films was analyzed by field emission scanning electron microscope (FE-SEM) and scanning probe microscopes (SPMs). Subsequently, the photocatalytic performances of the obtained nanosystems in the decomposition of methylene blue solution are discussed. The obtained results show that the dispersion of Au nanoparticles on the mesoporous TiO2 matrix will help enhancing the photocatalytic activity with respect to pure TiO₂ under visible light irradiation.     

碳纳米管修饰LaFeO3/TiO2复合材料的光催化性能与机理

采用超声辅助溶胶凝胶法制备了LaFeO₃颗粒,进一步以碳纳米管(CNTs)为基底和钛酸丁酯为前体,通过一步水热法煅烧合成CNTs/TiO₂/LaFeO₃(CTF)三元异质结光催化复合材料。通过扫描电子显微镜(SEM)、X射线衍射分析(XRD)、氮气吸附-解吸等温线(BET)、紫外-可见分光光度计(UV-Vis)、光致发光光谱(PL)等表征手段对材料的形貌与特征结构、比表面积和孔径结构以及光学特征进行了分析,并在紫外光下通过降解活性黑五(RB5)测试样品的光催化性能。结果表明,以CNTs作为载体,能够有效提升LaFeO₃/TiO₂复合材料的光催化性能。当CNTs在复合材料中的质量占比为5%时,150 W汞灯照射下RB5的50 min去除率可达99.5%。CNTs一方面通过增加复合材料的比较面积为催化反应的进行提供了更多的活性位点,更为重要的是,CNTs作为光生载流子传输的通道加快了电荷分离效率,提升了复合材料的降解能力和催化反应动力学进程。     

Co3O4负载rGO/g-C3N4臭氧光催化降解2,4-二氯苯氧乙酸活性研究

通过简单的水热法制备了Co₃O₄/rGO/g-C₃N₄催化剂,并在可见光照射下用于光催化臭氧氧化降解2,4-二氯苯氧乙酸(2,4-D)。利用XRD, SEM, TEM, XPS, UV-vis DRS, FT-IR和瞬态光电流对样品进行测试表征。研究表明,Co₃O₄, rGO和g-C₃N₄形成异质结后光生电子-空穴(e--h+)对的分离效率,e-的迁移能力以及光催化臭氧氧化活性都明显提升。此外,0.5Co₃O₄/0.25rGO/GCN对2,4-D具有100%的去除率,并具有最高反应速率(k=0.070 9 min^-1)。经过计算得出光催化臭氧氧化2,4-D的协同因子为3.91,表明光催化和臭氧氧化间具有较好的协同效应。活性组分的捕获实验结果表明h+和·OH是光催化臭氧氧化反应过程中的主要活性物种。此外,经过五次光催化臭氧氧化的循环实验,0.5Co₃O₄/0.25rGO/GCN样品表现处较好的稳定性,本文同时得出光催化臭氧氧化过程的反应机理。     

Synthesis of highly-active single-crystalline TiO2 nanorods and its application in environmental photocatalysis

Highly-active anatase TiO₂ nanorods have been successfully synthesized via a simple two-step method, hydrothermal treatment of anatase/rutile titanium dioxide nanoparticle powder in a composite-hydroxide eutectic system of 1:1 M KOH/NaOH, followed by acid post-treatment. The morphology and crystalline structure of the obtained nanorods were characterized using XRD, TEM, SEM/EDX and BET surface area analyzer. The obtained TiO₂ nanorods have a good crystallinity and a size distribution (about 4-16 nm); with the dimensions of 200-300 nm length and of 30-50 nm diameter. Compared with its precursor anatase/rutile TiO₂ nanoparticles and the titanate nanotubes, the pure anatase TiO₂ nanorods have a large specific surface area with a mesoporous structure. The photocatalytic performance of the prepared nanorods was tested in the degradation of the commercial Cibacrown Red (FN-R) textile dye, under UV irradiation. Single-crystalline anatase TiO₂ nanorods are more efficient for the dye removal.     

N2 adsorption curve of mesoporous SiO2: A neglected characterization technique

Mesoporous SiO₂ sieve and SiO₂ nanoparticles were synthesized by a traditional method in the presence and absence of tri-block copolymer surfactant P123 as structure directed agent respectively. The characterization results show that the mesoporous SiO₂ sieve has larger specific area (789 m²/g) than SiO₂ nanoparticles (373 m²/g), and there exists a substantial difference in the N₂ adsorption curves between the two samples. A speculative scheme shows that the formation of bottleneck during the N₂ adsorption process of mesoporous SiO₂ sieve should be responsible for the phenomenon.     

Mesoporous Au/TiO2 composites preparation,characterization, and photocatalytic properties

In this work, mesoporous Au/TiO₂ composites have been synthesized and tested on photodegradation of methylene blue dye solution. Mesoporous TiO₂ prepared at 450 °C using triblock polymer F127 as structure-directing agent was applied as substrate, while various HAuCl₄ concentrations were used for Au loading through deposition-precipitation method using urea as precipitator and hydrogen reducing process. The influences of Au loading on the microstructures of mesoporous TiO₂ including degree of dispersion, particle size, surface area, light absorption, and band gap were studied with transmission electron microscopy (TEM), X-ray diffraction (XRD), diffuse reflection infrared Fourier transformed spectroscopy (DRIFT), N₂ adsorption–desorption isotherm analysis (BET), and UV–Vis diffuse reflectance spectra. With Au loading, the size of TiO₂ nanoparticles in Au/TiO₂ composites is similar as that of TiO₂ substrate. However, the degree of dispersion was greatly improved. Furthermore, an obvious surface plasmon resonance centered at 570 nm was found in UV–Vis diffuse reflectance spectra for Au/TiO₂ composites. Au loading also induced an obvious red shift of light absorption from UV region to visible region and strengthened both UV and visible light absorption in contrast to substrate. Photodegradation results verified that photocatalytic activity of mesoporous TiO₂ was improved by Au loading. 0.25%Au/TiO₂ composite showed the highest activity, which may be ascribed to its high surface hydroxyl content and the formed Schottky junction after Au loading. These results suggested that noble metal modification is a promising way to synthesize photocatalysts with both high activity and visible light sensitivity.     

Enhanced photocatalytic activity of mesoporous TiO2 with MgO coating

To improve the photocatalytic activity of TiO₂ on decomposing anionic surfactants, MgO-coated mesoporous TiO₂ was fabricated by evaporation induced self-assembly (EISA) combined with impregnation method. MgO was uniformly dispersed on the surface of TiO₂, which played the role of stabilizing the ordered mesostructure of TiO₂ and improving the adsorption of anion surfactants, while inhibiting the crystallization of TiO₂. The powders coated with 5 wt.% MgO showed the highest photocatalytic activity for the decomposition of sodium dodecylbenzenesulfonate-6 (DBS).     

等离子体电解氧化法制备多孔TiO2/V2O5复合物膜层及其增强光催化产氢活性

较差的光催化产氢效率极大地阻碍了TiO₂光催化剂的工业化应用。为此,本文在含有NH₄VO₃的磷酸盐溶液中,采用等离子体电解氧化(PEO)法制备了多孔TiO₂/V₂O₅复合膜光催化剂,通过扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射(XRD)、X射线光电子谱(XPS)和紫外可见漫反射光谱(UV-Vis DRS)对其组成、结构及光吸收性质进行了表征,并采用气相色谱评价了薄膜催化剂的光催化产氢性能,研究了电解液中NH₄VO₃含量对膜的结构、组成和光催化产氢性能的影响。结果表明:复合膜催化剂主要由锐钛矿和金红石型TiO₂组成,具有微孔结构,V₂O₅主要以无定形形式存在于膜中,与TiO₂有很强的相互作用,影响TiO₂的晶面间距。研究发现,元素V抑制了TiO₂的结晶和金红石型TiO₂的形成,扩大了薄膜的光学吸收范围。针对Na₂S+ Na₂SO₃溶液中的光催化产氢性能的研究显示,在质量浓度为1 g/L NH₄VO₃的电解液中制备的TiO₂/V₂O₅薄膜的光催化活性最高,优于近年来报道的其他光催化剂。光催化重复实验表明,该复合膜催化剂具有较高的稳定性和较为恒定的光催化活性。     

Microstructure and photocatalytic activity of mesoporous TiO2 film coated on an aluminum foam

A TiO₂ film was synthesized via a surfactant assisted sol-gel process and dip-coated on the surface of an open-celled aluminum foam. The film shows a typical mesoporous structure composed of anatase crystalline grains with the average size of 10 nm, and has the thickness of about 3.5 μm as well as the BET surface area of 78.1 m²/g. It exhibits high photocatalytic efficiency toward the decomposition of formaldehyde at continuous flow mode. The relatively small grain size of TiO₂ and relatively thick mesoporous structure, which is favorable for high photochemical activity and the mass transfer of the reactants, should be responsible for the properties.     

Pt-Cu2O/TiO2复合催化剂的制备及光催化制氢活性

采用化学沉积法制备了Cu_2O/TiO_2复合光催化剂。通过扫描电子显微镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、紫外-可见漫反射光谱(DRS)表征复合催化剂的微观形貌、元素组成、结构和光学特性。以H_2PtCl_6为无机前驱体对复合材料进行Pt负载,研究了不同Cu_2O含量对制氢活性的影响及不同光源下的制氢活性。结果表明,该复合催化剂表现出较好的光催化制氢活性,当Cu_2O的含量为1%(质量分数)时,氢气的产生量最高。