水热法制备Cu掺杂可见光催化剂BiVO4及其光催化性能研究

以Bi(NO3)3.5H2O、NH4VO3、Cu(NO3)2.3H2O为原料,采用水热法合成了Cu-BiVO4光催化剂,并利用X射线衍射(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)、紫外漫反射(UV-Vis)等测试手段对催化剂进行了表征.结果表明,提高前驱液pH值,可得到单斜晶系白钨矿型Cu-BiVO4光催化剂,BiVO4的晶型结构并未随着Cu掺入量的增加而改变.光催化剂中的Cu元素以CuO和Cu2O的形式存在.Cu的引入使可见光吸收带发生红移,吸收强度明显提高.可见光催化降解亚甲基蓝溶液的结果表明,Cu掺杂有利于提高BiVO4的活性.其中pH值为5.0、Cu掺入量为1.0wt%的BiVO4具有最好的光催化效果,可见光照射60 min后,对初始浓度为10 mg/L的亚甲基蓝溶液的最高降解率由纯BiVO4的57.4%提高到97.8%.并对Cu掺入后光催化活性提高的机理进行了分析.     

TiO_2/SiO_2/rGO复合材料的制备及光催化性能探讨研究

制备了一种新型TiO_2/SiO_2/氧化还原石墨烯(TiO_2/SiO_2/rGO)三元复合材料,并对该复合材料的晶型结构、功能基团、元素化学性质、表面形貌和吸附效果进行了表征和分析,研究了其对阳离子染料[亚甲基蓝(MB)、罗丹明B(RhB)]与阴离子染料[甲基橙(MO)]的吸附降解效果,并比较了不同配比材料对MO的吸附降解作用。结果表明:TiO_2/SiO_2/rGO三元复合材料对不同染料都具有较高的光催化活性,其中对MO的光催化吸附降解效果更好。rGO∶(TiO_2/SiO_2)=1∶1(质量比)时,三元复合材料的光催化性能最佳,最大光催化吸附降解效率可达86%。     

水热法制备海绵钛负载TiO2膜

以H2O2为氧化剂、KOH为矿化剂,采用一步水热法在多孔海绵钛载体上制备了颗粒大小约为0.5μm的四方状锐钛矿TiO2膜,并研究了产物TiO2膜对目标降解物亚甲基蓝溶液的光催化性能,探讨了矿化剂浓度对产物TiO2膜晶型、形貌及光催化性能的影响.结果表明,KOH矿化剂有利于TiO2膜在海绵钛表面的生成与晶化,当KOH在0.12mol/L时,海绵钛负载TiO2膜有着最佳的光催化性能:光催化反应45min,亚甲基蓝溶液的降解率达95%.采用该法制备的TiO2光催化剂回收简单,反复利用后,其光催化性能无明显下降.     

Sm3+和Gd3+共掺杂TiO2粉体的制备和性能表征

采用溶胶-凝胶法制备了纯TiO2,1%Sm3+或2%Gd3+单掺杂和1%Sm3+/2%Gd3+共掺杂TiO2复合粉体,采用XRD和SEM/EDAX等技术进行表征。以对亚甲基蓝的光催化降解为目标反应,评价了TiO2复合粉体的光催化活性,探讨了Sm3+/Gd3+共掺杂、亚甲基蓝初始浓度和粉体投加量对TiO2粉体光催化活性的影响机制。结果表明,Sm3+/Gd3+共掺杂可以显著提高TiO2粉体的光催化活性;Sm3+/Gd3+共掺杂在TiO2粉体中产生协同作用,抑制了TiO2由锐钛矿相向金红石相转变,使TiO2粒径尺寸减小,增大了TiO2的晶格畸变。当亚甲基蓝初始浓度为4mg/L和粉体投加量为2g/L时,TiO2复合粉体的光催化活性最高,对亚甲基蓝光催化降解率达99.71%;降解亚甲基蓝反应符合Langmuir-Hinshelwood动力学方程。     

La-TiO_2/Hβ复合光催化剂降解模拟染料废水

用共沉淀法制备了新型La-TiO2/Hβ复合光催化剂,并以亚甲基蓝溶液为模拟废水,探讨了其对亚甲基蓝溶液的光催化降解效果,优化了降解条件。结果表明,La-TiO2/Hβ复合光催化剂降解25mL亚甲基蓝溶液的适宜条件是:亚甲基蓝溶液初始浓度为20mg/L,光照时间为30min,氧化剂H2O2用量为2.0mL,催化剂用量为2.4g/L。在此反应条件下,亚甲基蓝降解率达到98.2%,且催化剂重复使用3次后催化活性基本不变。     

水热法合成TiO2/Fe3+光催化剂及其氧化降解亚甲基蓝

以硫酸钛为钛源,采用水热法合成了TiO2/Fe3+光催化剂,利用XRD对产物晶体结构进行表征,研究在紫外光(365nm)照射下用合成的TiO2/Fe3+粉末催化降解亚甲基蓝的效果,分析了亚甲基蓝初始浓度、TiO2/Fe3+用量、掺Fe3+量、光照时间和溶液初始pH值等因素的影响;考察了溶液初始pH值对TiO2/Fe3+粉末的吸附性能和光催化活性的影响。结果表明:合成的TiO2/Fe3+晶体为锐钛矿型(A-TiO2)。在4mg/L的亚甲基蓝溶液(pH=8)中,加入掺Fe3+量0.8%(摩尔分数)合成的TiO2/Fe3+粉末使其用量为0.6g/L,室温下紫外光照反应6h,亚甲基蓝的降解率达到98.2%。在上述优化条件下,当溶液的pH<6时,催化剂对亚甲基蓝的吸附量和光催化效率均较低,且二者随pH升高而显著增加;当pH≥6时,对亚甲基蓝的吸附作用较大,因此较明显地提高了光催化活性。     

磁控溅射制备Cu2O和Cu2O/TiO2复合膜及其光催化活性

采用直流反应磁控溅射的方法在普通玻璃上沉积得到Cu2O、TiO2和Cu2O/TiO2复合薄膜.用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和X射线能谱仪(EDS)对薄膜的晶体结构、表面形态和薄膜元素组成进行了分析.XRD结果表明,当反应溅射时间为5 min时,Cu2O薄膜由单一的(111)晶面组成;反应时间的延长促进了Cu2O(110)和(220)晶面的生长.通过计算得出Cu2O(111)更有利于对O2的吸附.进一步使用氙灯作为光源,用薄膜对亚甲基蓝(MB)的降解率来表征光催化活性.结果表明,Cu2O/TiO2复合薄膜的光催化效果随着Cu2O含量的增加升高而后降低,当Cu2O含量为2.6mol%时,光催化活性最高.光催化效率的提高主要归因于Cu2O的加入引起光生电子-空穴的分离,而过量的Cu2O会延长光生电子迁移到Cu2O/TiO2界面和空穴迁移至表面所需要的时间,使电子和空穴复合的几率增大,从而降低了量子效率.     

我国几种含钛物料作为光催化材料降解亚甲基蓝的实验研究

半导体光催化氧化技术是一种新型的现代化水处理技术,对多种有机物有明显的降解效果,具有广泛的前景,近年来,半导体光催化氧化已成为光化学领域和环保领域中的研究热点之一.实验研究了处理后的几种含钛物料对水溶液中染料亚甲基蓝降解的过程,讨论了其光催化活性与其TiO2含量、溶液的PH值、氧化剂加入及外加电场的关系.结果表明五种含钛物料均具有光催化活性,光催化活性与其TiO2含量有关;降解染料亚甲基蓝时与溶液PH有关,PH=10时光催化效果最好;氧化剂加入、外加电场可提高光催化反应速度.     

掺杂钒酸铋的光催化性能研究

以Bi(NO3)3.5H2O和NH4VO3为原料,水热法合成了单斜相BiVO4粉体。利用X射线衍射、透射电镜、紫外可见漫反射对所合成产物进行了表征,并与高温固相法合成的产物进行了对比。用浸渍法对水热法合成产物进行了9种元素的掺杂,对掺杂BiVO4进行了光催化降解亚甲基蓝性能的研究。结果表明,Cu掺杂BiVO4显示出最大的光催化降解速率,2h降解率可达82%,而Ce掺杂降解能力降低,Si掺杂提高了吸附性。     

静电纺丝制备Fe2O3-TiO2纳米纤维及光催化性能研究

采用静电纺丝法制备了Fe2O3掺杂纳米TiO2的有机无机PVP/Fe2O3-TiO2纤维,经高温焙烧得到Fe2O3-TiO2纳米纤维。利用差动-热重(DSC-TGA)、傅里叶红外光谱(FT-IR)、扫描电镜(SEM)、XRD和比表面积分析仪等对样品进行了表征。以10mg/L亚甲基蓝溶液为底物,研究了Fe2O3掺杂量和焙烧温度等对亚甲基蓝太阳光催化降解效果的影响。结果表明,掺杂量为0.08%、焙烧温度为500℃得到的Fe2O3-TiO2纳米纤维光降解效果最好,达到96.3%,重复使用7次降解率仍在90%以上。     

Cu/还原氧化石墨烯光催化复合材料的制备及其光催化性能

以乙酸铜和氧化石墨烯（GO）为原料,抗坏血酸为还原剂,采用液相化学法合成Cu/还原氧化石墨烯（Cu/RGO）复合材料。通过XRD、SEM、TEM、FTIR和Raman对材料结构及形貌进行表征,并考察Cu/RGO复合材料在H₂O₂辅助作用下对亚甲基蓝（MB）的光催化作用。结果表明：Cu颗粒均匀分布在RGO片层上,相比于纯Cu,Cu/RGO复合材料的光催化性能明显提高,Cu/RGO复合材料用量为0.06 g/L时,对MB显示出最佳的催化效果,200 min内脱色率达到了92.5%,经过5次循环后脱色率仍有88.0%以上。     

High-yield synthesis of well-crystalline alpha-Fe2O3 nanoparticles: structural, optical and photocatalytic properties

In this paper, the high-yield facile synthesis, detailed characterization and photocatalytic application of alpha-Fe2O3 nanoparticles are reported. The synthesis was done via simple hydrothermal process by using aqueous mixtures of iron chloride, hexamethylenediamine and NH3 x H2O at 110 degrees C. The morphologies of the synthesized products were examined by using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) which confirmed that the synthesized structures are almost spherical shaped nanoparticles with the average diameters of -35 +/- 5 nm, and are grown in high yield. The detailed structural characterizations and composition of the as-synthesized nanoparticles were investigated by using X-ray diffraction (XRD), high-resolution TEM (HRTEM), energy dispersive spectroscopy (EDS) attached with FESEM and Fourier transform infrared spectroscopy (FTIR) which substantiated that the as-synthesized nanoparticles are well crystalline and pure alpha-Fe2O3. The UV-Vis absorption spectrum of the synthesized nanoparticles demonstrated the existence of two optical band gaps which correspond to direct and indirect transitions, respectively. The as-synthesized alpha-Fe2O3 nanoparticles exhibit good photocatalytic properties on photocatalytic degradation of methylene blue.     

Following charge separation on the nanoscale in Cu₂O-Au nanoframe hollow nanoparticles

Cu(2)O-Au nanoframes with different nanolayer thicknesses of Cu(2)O were prepared, and their photocatalytic properties in aqueous solutions were studied. Cu(2)O semiconductor excitation leads to electron-hole separation. In aqueous solution, the hole is known to oxidize water to produce hydroxyl radicals whose concentration (and that of the holes) can be monitored by the rate of the degradation of dissolved methylene blue dye. The exciton lifetime is determined by femtosecond techniques and is determined by electron-hole recombination which depends on the rates of a number of competing processes such as, electron or hole transfer to an acceptor such as a gold nanoframe and/or the electron or hole trapping processes at the Cu(2)O-Au nanoframe interface. We measured the exciton lifetime as a function of the average Cu(2)O-Au layer separation. A good correlation was found between the rate of the photocatalytic degradation of methylene blue and the exciton lifetime. The exciton lifetime is found to increase as the Cu(2)O thickness is increased. This leads to an increase in the electron-hole separation time and thus an increase in the hole (and so the hydroxyl radical) concentration leading to an observed enhanced rate of the dye degradation.     

Fe~(3+)/TiO_2纳米薄膜的亲水性及光催化性能

采用溶胶-凝胶法制备了一系列不同Fe3+含量的Fe3+/Ti O2纳米薄膜,运用X射线衍射仪、扫描电子显微镜、紫外可见分光光度计等手段对Fe3+/Ti O2进行了表征,并利用接触角测量仪考察了Fe3+含量、保存时间以及薄膜层数对亲水性的影响,同时以8 W(λ=254 nm)的UV灯作为光源,评价了各薄膜光催化降解亚甲基蓝的活性.结果表明,当Fe3+质量分数为0.5%时,Ti O2薄膜催化降解染料的活性得到大幅提高,同时也表现出了最好的亲水性,其薄膜表面与水的接触角几乎为0°.     

Self-assembly of the Ag deposited ZnO/carbon nanospheres: A resourceful photocatalyst for efficient photocatalytic degradation of methylene blue dye in water

Carbon nanospheres (CNSs) are synthesized by pyrolysis of benzene at 1000?°C. Various UV-light photocatalysts of ZnO/CNSs and Ag-ZnO/CNSs (AZCN) composites are synthesized on the surface of CNSs using a facile chemical precipitation method. Morphological and optical properties of the as-synthesized photocatalysts are characterized by scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy, UV-Vis spectroscopy, photoluminescence and Raman spectroscopy. Photocatalytic degradation efficiency of methylene blue dye is investigated to examine the photocatalytic activity of synthesized photocatalysts. It is found that as-synthesized ZnO/CNSs composite can degrade higher methylene blue dye (～85.6%) after 25?min of UV irradiation in comparison with that of CNSs. A prominent improvement in the photodegradation is attained by depositing metal (Ag) particles on the surface of ZnO/CNSs composite. AZCN composite displays the enhanced photocatalytic degradation performance (～95% after 15?min of UV light) in high concentration of methylene blue dye. Furthermore, stability performance is studied by recycling the AZCN composite photocatalyst. It is found that the photocatalytic activity of AZCN composite is only slightly decreased even after five cycles. Present work demonstrates that AZCN composite show a great potential in the treatment of organic pollutants for wastewater treatment.     

片状磁性纳米TiO2/SiO2/NiFe2O4制备及光催化性能

以锐钛矿磁性纳米TiO2/SiO2/NiFe2O4(TSN)为原料,采用水热法制备了片状磁性纳米TSN.利用XRD、TEM等技术对样品进行了表征.水热法处理后核壳结构的TSN部分转变为片状,催化剂磁性增强.以亚甲基兰溶液为模拟水样测试了样品的光催化性能,考察了催化剂加入量、反应时间、pH值等因素的影响.实验表明:片状磁性纳米TSN光催化性能明显优于粒状TSN.片状TSN具有良好的吸附性能,提高了光催化反应的初始速率.用于处理亚甲基兰废水时受pH值的影响较小,1小时的脱色率在90%以上.     

水热法制备纤维素基CdS纳米复合材料及其光催化性能研究

以棉花为纤维素基质,CdCl_2·21/2H_2O和L-半胱氨酸为原料,采用水热法制备了纤维素基CdS纳米复合材料。以亚甲基蓝(MB)为目标降解物,研究了反应时间和反应温度对该复合材料光催化性能的影响,通过XRD、SEM、FT-IR和UV-VisDRS对不同温度下制得的复合材料进行了结构表征。结果表明,反应温度为影响纤维素基CdS样品光催化活性的关键因素,且对样品中CdS的微观结构有显著影响。当反应温度为120℃时,样品的光催化活性最佳,反应50min对MB溶液的光降解率达到94.78%。经过3次循环其光降解率基本保持不变,表明纤维素基CdS是一种稳定有效的光催化剂。光催化增强机理分析表明,CdS光生电子迁移至纤维素表面,实现了与光生空穴的有效分离,从而增强了材料的光催化性能。     

Photocatalytic degradation of azo dyes using Au:TiO2, gamma-Fe2O3:TiO2 functional nanosystems

We report photocatalytic degradation studies on Navy Blue HE2R (NB) dye on significant details as a representative from the class of azo dyes using functional nanosystems specifically designed to allow a strong photocatalytic activity. A modified sol-gel route was employed to synthesize Au and gamma-Fe2O3 modified TiO2 nanoparticles (NPs) at low temperature. The attachment strategy is better because it allows clear surface of TiO2 to remain open for photo-catalysis. X-ray diffraction, Raman and UV-VIS spectroscopy studies showed the presence of gold and iron oxide phases along-with the anatase TiO2 phase. TEM studies showed TiO2 nanocomposite particles of size approximately 10-12 nm. A detailed investigation on heterogeneous photocatalytic performance for Navy Blue HE2R dye was done using the as-synthesized catalysts Au:TiO2 and gamma-Fe2O3:TiO2 in aqueous suspension under 8 W low-pressure mercury vapour lamp irradiation. Also, the photocatalytic degradation of Amranth and Orange G azo dyes were studied. The surface modified TiO2 NPs showed significantly improved photocatalytic activity as compared to pure TiO2. Exposure of the dye to the UV light in the presence of pure and gold NPs attached TiO2 catalysts caused dye degradation of about approximately 20% and approximately 80%, respectively, in the first couple of hours. In the presence of gamma-Fe2O3 NPs attached TiO2, a remarkable approximately 95% degradation of the azo dye was observed only in the first 15 min of UV exposure. The process parameters for the optimum catalytic activity are established which lead to a complete decoloration and substantial dye degradation, supported by the values of the Chemical Oxygen Demand (COD) approximately 93% and Total Organic Carbon (TOC) approximately 65% of the treated dye solution after 5 hours on the employment of the UV/Au:TiO2/H2O2 photocatalytic process.     

铜掺杂纳米 TiO2 的制备及其抗菌性能研究

目的制备铜掺杂纳米二氧化钛抗菌材料,测定其金属溶出率,研究该材料的光催化活性及抗菌性能。方法通过水热合成法制备掺铜二氧化钛(TiO_2Cu)纳米材料,采用催化动力学法测定该材料Cu~(~(2+))溶出率,以亚甲蓝为光催化降解材料测定其光催化活性,以金黄色葡萄球菌为目标物,研究在紫外光和非光条件下TiO_2Cu纳米材料的抗菌性能。结果 TiO_2Cu纳米材料Cu~(2+)溶出率最大值为72.36%,在自然光和紫外灯光照下对亚甲蓝光催化降解率分别为95.06%和85.08%,光照下TiO_2Cu材料质量浓度达到10 mg/m L,与细菌共培养90 min后,抑菌率可达94%。结论采用冷冻干燥法制备的含铜量为0.2%的TiO_2Cu材料具有良好的光催化活性,在暗光和紫外光照下均具有一定的抗菌性能。