TiO2-Cu[HgI4]纳米复合材料的制备及其热致变色性能

以TiO₂为载体制备了TiO₂-Cu[HgI₄]纳米复合材料,利用HRTEM、XRD、DSC、UV-Vis等方法对该材料的结构及其热致变色性能进行了研究。研究表明,TiO₂-Cu[HgI₄]纳米复合材料具有较好的热致变色性能,随着nTiO₂/nCu[HgI₄]摩尔比值的增大,其可见光吸收性能增强,相变温度也相应升高。     

TiO2纳米纺锤体负载Pt在氧还原反应中的应用

燃料电池中催化剂的稳定性是影响其实际应用的关键问题之一。本研究合成了锐钛矿型纺锤状TiO₂纳米材料,并负载纳米Pt制备了TiO₂-Pt双组分复合催化材料。将其制作成电极材料后,进行了TEM、XRD、拉曼光谱、电化学特性分析。结果表明：TiO₂-Pt材料中Pt纳米颗粒的TEM形貌与TiO₂的表面亲和力有关;该双组分催化剂呈现出两个单独的氧还原反应（ORR）峰;在负载Pt后,材料电荷传输电阻明显减小,使得TiO₂-Pt中TiO₂纺锤体组分上的ORR性能明显增强;紫外光可同时促进TiO₂-Pt中两组分的ORR性能;TiO₂-Pt比炭黑负载Pt具有更好的稳定性。     

染料敏化太阳能电池光阳极的优化与性能研究

对染料敏化太阳能电池（DSSC）光阳极的制作工艺进行优化设计,在光阳极初始默认的制作工艺条件下,分别对影响DSSC光电性能的光阳极活性面积、TiO₂薄膜厚度、是否添加散射层、TiO₂薄膜烧结温度、化学处理方法和TiCl₄浓度影响因素逐一进行考察,最终确定了光电极的最佳制作工艺：光阳极活性层面积为0.4 cm × 0.4 cm,TiO₂薄膜厚度为19 μm,并加散射层,TiO₂薄膜电极的烧结温度为T₁ = 525℃、二次烧结温度为T₂ = 500℃,采用0.1 mol/L的TiCl₄水溶液进行化学处理,获得短路电流密度19.45 mA/cm²,光电转换效率8.42%。此制作工艺方法简单、光谱特性好、光电转换效率高,有利于DSSC的结构优化与推广应用。     

纳米氮化锆薄膜的光学性能研究

采用射频磁控溅射法在载玻片和硅片上制备了纳米氮化锆薄膜。结果表明,纳米氮化锆薄膜(10～29nm)呈非晶态,其光学特性在波长380～2700nm的范围内平均可见光透过率为82.86%,平均反射率低至10.78%。扫描隧道谱(SIS)分析表明薄膜禁带宽度E_g为2.99 eV,在可见光范围内光子多为透过,反射和吸收较弱。从薄膜的X光电子能谱图(XPS)可知,薄膜表面存在大量的ZrO_2,对于纳米级的氮化锆薄膜而言,表面相ZrO_2对整体光学性能的影响较大。     

纳米Fe2O3/硬脂酸/十八醇纳米复合相变蓄热材料的性能研究

针对有机相变材料热导率低的问题,将高热导率的纳米Fe₂O₃添加到硬脂酸/十八醇二元有机复合蓄热相变材料中,制备纳米复合蓄热相变材料。从分散剂的种类、分散剂与纳米材料的添加量以及超声时间4个方面研究其对纳米复合相变蓄热材料的稳定性及热物性的影响。结果表明,阴离子表面活性剂的分散效果优于阳离子和非离子表面活性剂。复合相变材料中添加质量分数为0.8%,十二烷基苯磺酸钠(SDBS)和质量分数为0.4%Fe₂O₃的体系,超声时间为80 min时,纳米Fe₂O₃在相变材料中的分散效果最好。添加纳米Fe₂O₃后复合蓄热相变材料的相变潜热及相变温度有所下降,热导率提高34.9%。300次热循环复合相变材料的相变温度波动区间不超过0.41℃,相变潜热波动区间不超过4.0%,热稳定性良好。     

CdS量子点敏化TiO_2纳米颗粒多孔薄膜太阳能电池性能研究

以CdS量子点敏化TiO2纳米颗粒多孔薄膜为光阳极,与多硫电解液和Pt对电极组装太阳能电池,研究了光阳极厚度和敏化周期对光伏性能的影响。结果表明,TiO2纳米颗粒多孔薄膜的最佳厚度为14μm,最佳CdS量子点敏化周期为20,由此得到的太阳能电池的短路电流密度J sc、光电转换效率η和量子效率分别为4.51 mA/cm2、0.76%和69%。在光阳极中采用TiO2纳米颗粒/TiO2纳米线多孔薄膜双层工作电极,TiO2纳米线散射层增加了对入射光的利用率,使电池在可见光波段的量子效率增加,从而使电池的短路电流密度J sc和光电转换效率分别比原来提高了11.6%和10.5%。     

高级氧化技术中分子筛负载纳米TiO2的光催化性能的研究

选择溶胶-凝胶方法制作纳米TiO₂,且将纳米TiO₂负载于分子筛上面。实验结果表明,与非负载光催化剂相比,负载光催化剂具体性能更优。针对目标物实行降解时,最优条件为,pH值是4.7,H₂O₂最初的物质的量浓度是25 mmol/L,甲基橙最初的质量浓度是20 mg/L,增加量是2 g;温度升高有利于降解;随应用频次提升,催化剂具体活性渐渐下降。     

基于磺酸化类石墨烯聚合物的纳米组装与复合研究

磺酸化类石墨烯聚合物(SGP)是富含磺酸化官能团并具有二维纳米结构特性的一类新型聚合物材料,其极高的亲水性为发展纳米组装和复合结构提供了新途径。介绍了利用SGP发展的具有优异力、电及电化学性能的三类复合材料:(1)通过聚乙烯醇(PVA)与SGP复合构筑具有高孔隙率的全固态电容器隔膜材料;(2)利用SGP富含官能团的特性,在其表面生长Co_3O_4的过程中抑制颗粒尺寸和维度,获得容量更高的复合电极材料;(3)利用SGP分散碳纳米管(CNT),通过与PVA复合得到的SGP/CNT/PVA柔性薄膜具有优异的力学特性。基于此,SGP有望在多功能复合组装中得到更为广泛的应用。     

紫外光下Ag掺杂TiO2薄膜基底对VO2相转变温度的影响

利用溶胶−凝胶法和浸渍提拉技术制备了不同结构银掺杂二氧化钛薄膜为基底材料的VO₂薄膜,考察了Ag分级配置的二氧化钛薄膜基底材料对VO₂薄膜相变温度的影响。在紫外灯照射下测试面内电阻随温度,电压随时间的变化,结果表明基底材料为Ag分级配置的VO₂/TiO₂薄膜相变温度点明显降低。这可能是由于光照条件下空穴载流子从基底材料注入到VO₂薄膜导致相变温度点偏移。因此,不同结构银掺杂二氧化钛薄膜为基底材料的VO2薄膜能够根据环境温度和太阳光线变化而应用于光热致变色智能窗。     

水热法制备TiO2纳米晶胶体及其在DSSC电池中的应用

采用钛酸异丙酯作前驱体，利用水热法制备了TiO2纳米溶胶溶液。以此制备了染料敏化太阳能电池的光阳极并组装电池。对产物采用激光粒度仪（HPPS）、X射线衍射（XRD）、扫描电镜（SEM）等进行表征。XRD显示了TiO2纳米颗粒为纯锐钛矿结构，SEM观察薄膜电极呈多孔结构。表征电池的光电化学性能，所制备的TiO2纳米晶薄膜的光电转换效率达到3．03％。     

Interfacial charge transfer and photocatalytic activity in a reverse designed Bi2O3/TiO2 core-shell

In this study, the electronic and photocatalytic properties of core-shell heterojunctions photocatalysts with reversible configuration of TiO₂ and Bi₂O₃ layers were studied. The core-shell nanostructure, obtained by efficient control of the sol-gel polymerization and impregnation method of variable precursors of semiconductors, makes it possible to study selectively the role of the interfacial charge transfer in each configuration. The morphological, optical, and chemical composition of the core-shell nanostructures were characterized by high-resolution transmission electron microscopy, UV-visible spectroscopy and X-ray photoelectron spectroscopy. The results show the formation of homogenous TiO₂ anatase and Bi₂O₃ layers with a thickness of around 10 and 8 nm, respectively. The interfacial charge carrier dynamic was tracked using time resolved microwave conductivity and transition photocurrent density. The charge transfer, their density, and lifetime were found to rely on the layout layers in the core-shell nanostructure. In optimal core-shell design, Bi₂O₃ collects holes from TiO₂, leaving electrons free to react and increase by 5 times the photocatalytic efficiency toward H₂ generation. This study provides new insight into the importance of the design and elaboration of optimal heterojunction based on the photocatalyst system to improve the photocatalytic activity.     

The influence of acid treatment of TiO2 porous film electrode on photoelectric performance of dye-sensitized solar cell

A dye-sensitized solar cell (DYSC) was assembled by adsorbing cis-dithiocyanato-bis (2,2^′-bipyridyl-4,4^′-dicarboxylate) ruthenium (II) onto TiO₂ porous film. The influence of acid treatment of TiO₂ electrode with different kinds and concentrations on the photoelectric performance of DYSC was investigated. It was found that DYSC had better photoelectric performance when the TiO₂ electrode was treated by hydrochloric acid than that by sulfuric acid, nitric acid and phosphoric acid. When the concentration of hydrochloric acid to treat TiO₂ electrode increases from 0 to 0.10 M, the fill factor of DYSC increases, the short-circuit current decreases, the open-circuit photovoltage increases and the absorption amount for TiO₂ porous film to dye molecules decreases. The acid treatment of TiO₂ electrode provides useful information on the mechanism of energy conversion of DYSC.     

Physicochemical properties and photocatalytic hydrogen evolution of TiO2 films prepared by sol–gel processes

Anatase TiO₂ films were obtained on glass substrates using a sol–gel method using titanium isopropoxide as a precursor. The thickness of the film was about 140 nm for one coating, and the thickness is controlled by the number of coating cycles. The spectra of UV-VIS absorption indicated that the absorption edge of the TiO₂ films is ca. 385 nm, corresponding to the band gap energy of 3.20 eV. We obtained TiO₂ films having a high activity for the hydrogen evolution from photocatalytic water cleavage. By loading with 0.3 wt% Pt rate of hydrogen production increases. No influence of film thickness and calcination temperature on the photocatalytic property is observed.     

Chemical bath deposition of Cds buffer layer for GIGS solar cells

We investigated the chemical bath deposition of US thin flims on the Cu(In,Ga)Se₂ (GIGS) absorber layers and glasses. The process of the chemical bath deposition of US layer affected the performance of the CIGS solar cells. The CdS layers were deposited on the CIGS film from CdI₂, thiourea (NH₂CSNHn₂) and ammonia solutions. The influence of pH on the chemical bath deposition process was studied. The surfaces of the US films were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The compositions of the obtained CdS layers were analyzed by Auger electron spectroscopy (AES). The performance of the CIGS solar cells was discussed on the basis of the characteristics of the chemical bath deposited layer. We have successfully fabricated a high-efficiency CIGS solar cell with an efficiency of 17% using a US layer with stoichiometric composition.     

染料敏化太阳能电池电子传输的数值模拟研究

基于电子传输的扩散理论建立了染料敏化太阳能电池(DSSC)的连续性方程,使用适合于二氧化钛(TiO₂)作为光阳极的内部参数,对DSSC电子注入和传输的内在机理进行研究。分别考查温度、TiO₂膜厚、电子寿命、电子扩散系数、光照强度、吸收系数等因素对DSSC光电性能的影响,为DSSC性能的改进及光电转换效率的提高提供理论指导。     

Enhancing the photoelectrochemical performance of p-silicon through TiO2 coating decorated with mesoporous MoS2

MoS₂ is a promising electrocatalyst for hydrogen evolution reaction and a good candidate for cocatalyst to enhance the photoelectrochemical (PEC) performance of Si-based photoelectrode in aqueous electrolytes. The main challenge lies in the optimization of the microstructure of MoS₂, to improve its catalytic activity and to construct a mechanically and chemically stable cocatalyst/Si photocathode. In this paper, a highly-ordered mesoporous MoS₂ was synthesized and decorated onto a TiO₂ protected p-silicon substrate. An additional TiO₂ necking was introduced to strengthen the bonding between the MoS₂ particles and the TiO₂ layer. This meso-MoS₂/TiO₂/p-Si hybrid photocathode exhibited significantly enhanced PEC performance, where an onset potential of +0.06 V (versus RHE) and a current density of −1.8 mA/cm² at 0 V (versus RHE) with a Faradaic efficiency close to 100% was achieved in 0.5 mol/L H₂SO₄. Additionally, this meso-MoS₂/TiO₂/p-Si photocathode showed an excellent PEC ability and durability in alkaline media. This paper provides a promising strategy to enhance and protect the photocathode through high-performance surface cocatalysts.     

A mini-review of ferrites-based photocatalyst on application of hydrogen production

Photocatalytic water splitting for hydrogen production is a promising strategy to produce renewable energy and decrease production cost. Spinel-ferrites are potential photocatalysts in photocatalytic reaction system due to their room temperature magnetization, the high thermal and chemical stability, narrow bandgap with broader visible light absorption, and proper conduction band energy level with strong oxidation activity for water or organic compounds. However, the fast recombination of the photoexcited electrons and holes is a critical drawback of ferrites. Therefore, the features of crystallinity, particle size, specific surface area, morphology, and band energy structure have been summarized and investigated to solve this issue. Moreover, composites construction with ferrites and the popular support of TiO₂ or g-C₃N₄ are also summarized to illustrate the advanced improvement in photocatalytic hydrogen production. It has been shown that ferrites could induce the formation of metal ions impurity energy levels in TiO₂, and the strong oxidation activity of ferrites could accelerate the oxidation reaction kinetics in both TiO₂/ferrites and g-C₃N₄/ferrites systems. Furthermore, two representative reports of CaFe₂O₄/MgFe₂O₄ composite and ZnFe₂O₄/CdS composite are used to show the efficient heterojunction in a ferrite/ferrite composite and the ability of resistance to photo-corrosion, respectively.