N-doped graphene quantum dot-decorated N-TiO2/P-doped porous hollow g-C_(3)N_(4) nanotube composite photocatalysts for antibiotic photodegradation and H2 production

Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped with 0.1wt% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, which is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction between N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared with those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathways of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion.

Surface Microstructure Characterization of Sol-gel Derived Porous TiO_2 Thin Films

Porous TiO2 thin films were prepared from alkoxide solutions with and without polyethylene glycol (PEG) by sol-get route on soda lime glass, and were characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results show that TiO2 film prepared from precursor solution without PEG is composed of spherical particles of about 100 nm and several nanometer mesoporous pores. With the increase of the amount of PEG added to the precursor solution, the diameter and the depth of the pores in the resultant films increas on the decomposition of PEG during heat-treatment, which lead to them increase of the surface roughness of the films. XRD and TEM results show that the single anatase phase is precipitated and there are some orientation effects in (101) direction.

Fabrication and photodegradation properties of TiO_2 nanotubes on porous Ti by anodization

Both Ti foil and porous Ti were anodized in 0.5%HF and in ethylene glycol electrolyte containing 0.5%NH4F(mass fraction) separately. The results show that TiO2 nanotubes can be formed on Ti foil by both processes, whereas TiO2 nanotubes can be formed on porous Ti only in the second process. The overhigh current density led to the failure of the formation nanotubes on porous Ti in 0.5%HF electrolyte. TiO2 nanotubes were characterized by SEM and XRD. TiO2 nanotubes on porous Ti were thinner than those on Ti foil. Anatase was formed when TiO2 nanotubes were annealed at 400 °C and fully turned into rutile at 700 °C. To obtain good photodegradation, the optimal heat treatment temperature of TiO2 nanotubes was 450 °C. The porosity of the substrates influenced photodegradation properties. TiO2 nanotubes on porous Ti with 60% porosity had the best photodegradation.

Rapid communication Preparation of TiO_2 nanometer thin films with high photocatalytic activity by reverse micellar method

Two kinds of TiO_2 nanometer thin films were prepared on stainless steel bythe reverse micellar and sol-gel methods, respectively. The calcined TiO_ 2 thin films werecharacterized by X-ray diffraction (XRD), atomic force microscopy (AFM), BET surface area and X-rayphotoelectron spectroscopy (XPS). Photocatalytic activity was evaluated by photocatalyticdecoloration of methyl orange aqueous solution. The results showed that the TiO_2 thin filmsprepared by reverse micellar method (designated as RM-TiO_2 films) showed higher photocatalyticactivity than those by sol-gel method (designated as SG-TiO_2 films). This is attributed to the factthat the former is composed of smaller monodispersed spherical particles with a size of about 15 nmand possesses higher surface areas.

Preparation and Characterization of Nano-ZnFe_2O_4/TiO_2 Films

The nano-ZnFe2O4/TiO2 films possess the functions of desulfurization and degradation for organic pollutants. The sols of ZnFe2O4/TiO2 were prepared by sol-gel method and coated on glass and porous ceramic by vertical coating and dipping-lift processes, respectively, and the samples were obtained after drying and sintering. The composition, appearance, absorption spectrum of the films, and the influence of the film on porous ceramic performances were analyzed using SEM, AFM, UVVis spectrometer, and mercury porosimeter, respectively, to determine the operation parameters of the multifunction porous ceramic elements for gas-purification.

In-situ fabrication of dual porous titanium dioxide films as anode for carbon cathode based perovskite solar cell

We develop a dual porous （DP） TiO2 film for the electron transporting layer （ETL） in carbon cathode based perovskite solar cells （C-PSCs）. The DP TiO2 film was synthesized via a facile PS-templated method with the thickness being controlled by the spin-coating speed. It was found that there is an optimum DP TiO2 film thickness for achieving an effective ETL, a suitable perovskite]TiO2 interface, an efficient light harvester and thus a high performance C-PSC. In particular, such a DP TiO2 film can act as a scaffold for complete-filling of the pores with perovskite and for forming high-quality perovskite crystals that are seamlessly interfaced with Ti02 to enhance interracial charge injection. Leveraging the unique advantages of DP TiO2 ETL, together with a dense-packed and pinhole-free TiO2 compact layer, PCE of the C-PSCs has reached 9.81% with good stability.

Preparation and Photocatalytic Property of Porous TiO_2 Film with Net-like Framework

By the UV-curing method, a porous TiO2 film with net-like framework has been prepared. The characterization results of the porous TiO2 film by means of SEM, TEM, XRD, and N2 adsorption-desorption analysis show that the net-like framework of the porous TiO2 film is composed of TiO2 nanoparticles, forming three dimensional porous structure. The porous TiO2 film exhibits higher photocatalytic activity for the degradation of methylene blue（MB） dye compared with the conventional dense TiO2 film.

Influence of TiO_2 seeding layers on phase composition of lead magnesium niobate-lead titanate thin films prepared by RF magnetron sputtering

The influence of amorphous TiO_2 seeding layers on the phase composition of lead magnesium niobate-lead titanate(0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3,PMN-PT) films deposited on Pt/Ti/SiO2/Si substrate by RF magnetron sputtering was examined.The relation between seeding layer thickness and phase composition at different post annealing temperature was observed by XRD.The thickness of amorphous TiO2 seeding layer and post annealing temperature had remarkable effects on PMN-PT film phase composition.When amorphous seeding layer becomes thick,a new phase of Nb2O5 exists in the films.Only when the seeding layer thickness is suitable,the film with pure perovskite phase can be attained.

Fabrication and Fluorescence Study of Sensitizing Dye/TiO_2 Films

Fluorescence spectra of the sensitizing dye/ TiO2 bilayer films were studied. Charge-transfer complexes were formed in the above bilayer.

Sensitizing Mechanism and Adsorption Properties of Dye-sensitized TiO_2 Thin Films

The dye-sensitized TiO2 complex films were prepared by the dye coat onto TiO2 surfaces, and the sensitizing mechanism and adsorption properties of the dye-sensitized TiO2 complex films were investigated. The influence of the application conditions of dye adsorbed on TiO2 films on the amount of dye adsorption was discussed. Experimental results show that the concentration, the temperature of dye solutions and the dipping time of TiO2 films in the dye solutions have a significant influence on the amount of dye adsorption. Cell test indicates that the conversion efficiency of light to electricity increases with the amount of dye adsorption.

Time-resolved Microwave Conductivity Studies on the Chemical Treatment of the Nanocrystalline Porous TiO2 Films

Effect of Ti(iso-C3H7O)4 treatment on the photoinduced charge carrier kinetics of nanocrystalline porous TiO2 films is studied by time-resolved microwave conductivity measurements. Analysis of the transient photoconductivity decays indicates that Ti(iso-C3H7O)4 treatment leads to an increased concentration of photogenerated charge carriers and a fast interfacial transfer rate of holes via the surface modification of the freshly growing TiO2 nanocrystallites.

Synthesis and Characterization of TiO₂Porous Films for Heterogeneous Photocatalysis

Heterogeneous photocatalysis is one of the advanced oxidation processes (AOP’s). These are very used nowadays for their implementation in tertiary water treatment with solar activation, with very good results. In this study, TiO2 porous films were synthesized by sol-gel method. Polyethylene glycol (PEG) 4000 was used as a templating reagent, which is oxidized at a lower temperature than TiO2. This allows the formation of a “skeleton” of porous TiO2 with increased surface area, resulting in higher photocatalytic activity. The film characterization was made with help of FE-SEM microscope, XRD diffractometer and scotch tape test. Finally, the oxidation experiments were performed using methylene blue as a model pollutant and they revealed an increase in the photocatalytic activity of porous films in comparison with the non-porous films.

纳米TiO_(2)对NH_(3)-H_(2)O-LiBr工质降膜吸收性能的影响

为了探讨纳米TiO_(2)对三元NH_(3)-H_(2)O-LiBr工质降膜吸收的影响,本文利用数值分析建立了三元工作流体薄膜吸收的连续方程、能量方程和组分质量平衡方程,采用Matlab软件进行编程和计算纳米流体的降膜吸收性能,将其与实验数据进行对比验证,并进一步分析了纳米TiO_(2)质量分数、初始氨浓度、初始温度、冷却水进口温度、吸收压力和下降薄膜管长度对薄膜吸收性能的影响。研究表明:添加纳米TiO_(2)可以增强降膜吸收的传质速率,主要原因为液膜中氨的扩散系数增加。当纳米TiO_(2)质量分数从0%增加到0.1%、0.3%和0.5%时,扩散系数分别增加了3.44倍、6.42倍和11.76倍。此外,增加初始氨浓度、降低初始温度、提高冷却水进口温度或降低吸收压力都可以提高最终溶液的饱和度。

(Ag,Cu)/TiO_(2)汽车玻璃隔热膜的制备与表征

利用磁控溅射技术制备由金属(Ag,Cu)膜、介质层TiO_(2)膜组成的双层汽车玻璃隔热膜样品。利用单因素分析法考察了溅射时间、溅射功率和Ar溅射流量三个因素对(Ag,Cu)/TiO_(2)汽车玻璃隔热膜透光隔热性能的影响。实验结果表明,在在本底真空度3×10^(-3) Pa,溅射气压2.1 Pa条件下,靶基距均为70 mm时,金属(Ag,Cu)膜溅射时间18 s,溅射功率80 W,Ar溅射流量20 sccm;介质层TiO_(2)膜溅射时间50 min,溅射功率115 W,溅射流量25 sccm时,(Ag,Cu)/TiO_(2)汽车玻璃隔热膜的透光隔热性能最佳。

TiCl_4水解法制备TiO_2薄膜的表征及光催化性能

以TiCl4水解法,采用浸渍提拉法在玻璃片上制备TiO2纳米薄膜。用XRD及SEM、EDS测定和表征TiO2薄膜的表面形貌和结构特性,以UV吸收光谱和可见光透光率表征薄膜的光学特性。结果表明,所得薄膜负载质量与镀膜次数有很好的线性关系,镀膜4次的TiO2薄膜具有表面均匀、厚度约为0 192μm,粒子粒径约为5.0nm,对紫外光强烈吸收并有红移拓宽。TiO2薄膜作为催化剂对500mL的20mg/L乙酸的降解率达到75.9%,比等负载量的粉末TiO2光催化的48.0%降解率高27.9%。

脉冲激光沉积过程中TiO_(2)等离子体状态诊断及薄膜特性的研究

脉冲激光沉积技术由于具有较高的沉积速率和良好的兼容性,已广泛应用于各种纳米薄膜材料的制备.探究激光等离子体状态与沉积薄膜特性之间的关系,有助于进一步调控与优化脉冲激光技术对薄膜材料的沉积.本文将等离子体状态诊断与沉积薄膜性能相结合,讨论了不同脉冲激光能量下等离子体状态对沉积薄膜性能的影响.结果表明,低烧蚀能量下产生的等离子体更有助于获得质地更好,且与靶材晶相一致的优良薄膜材料.该结果也为探索和调控沉积过程提供参考.

TiO_2光催化降解聚乙烯薄膜

以快速溶胶法制备了纳米TiO2光催化剂,用于室温下固相光催化降解聚乙烯(PE)包装薄膜的研究。对催化剂和薄膜进行了X射线衍射分析,傅立叶红外光谱分析,扫描电子显微镜形貌观察。结果表明,15W紫外光辐射240h后,PE质量损失为7.66%,金红石型纳米TiO2光催化剂使PE质量损失14.93%,锐钛矿型纳米TiO2光催化剂使PE质量损失23.97%;TiO2加速了高分子碳链的断裂和光氧化,在薄膜表面形成大量的凹坑,降解产物中小分子量的石蜡含量明显增高,锐钛矿型纳米TiO2光催化降解PE的活性高于金红石型纳米TiO2。

纳米保鲜型食品新鲜度指示材料的制备及其应用

随着食品包装在食品品质安全中扮演越来越重要的角色,新鲜度指示材料已成为当下的研究热点。一方面可以阻隔微生物的进入,有效抑制微生物的滋生和繁殖,确保食品包装内部环境的稳定性,进而改变食品品质;另一方面,它可以监测并指示包装内部的环境变化反馈食品品质信息。本文以食品级高分子材料高直链玉米淀粉(HAMS)、聚乙烯醇(PVA)为主要原料,负载复合型pH指示剂MR-BB(甲基红与溴百里酚蓝混合物),利用超声分散法将高抑菌性的纳米二氧化钛(nano-TiO_(2))分散于其中,同时利用交联剂甘油、疏水剂尿素,构建高分子三维立体网状结构,优化其物化性质。用溶液聚合和流延成膜的方法制备具有p H响应性的纳米保鲜-食品新鲜度指示材料(AFIF)。综合各项基础性能可知,高直链玉米淀粉和PVA添加量的体积比为7∶3,甘油添加量为2%,尿素添加量为2%。构筑牛奶新鲜度下降的环境模型(二氧化碳气氛),通过数据对比和优化AFIF膜的p H响应性的灵敏度及其准确性,可知MR-BB最佳体积比为1∶2,最佳添加量为6%。对AFIF膜的抑菌性能以及对市售牛奶的保鲜性能进行分析,当nano-TiO_(2)的添加量为0.15 g时(每100 mL膜液),抑菌率可高达80%左右。实际应用结果表明,常温贮藏时,非抗菌型AFIF膜组在36 h后液态奶失去可食用价值,而AFIF膜包装的牛奶仍保持较好的品质,直到72 h,该组液态奶失去食用价值,此时AFIF膜对变质牛奶的检出时间为3 min 35 s,膜颜色由蓝绿色(初始)转变为深黄色,初始变色面积为10%(膜面积为9 cm^(2)),变色完成时间为33 min 31 s,色差值可达5.91。AFIF膜对市售液态牛乳具有明确的保鲜和新鲜度指示功能。

连续片状纳米TiO_2薄膜的制备和表征(英文)

采用溶胶 凝胶法,通过在制备过程中加入丙烯酸对纳米TiO2胶体颗粒进行表面修饰以及加入引发剂偶氮双异丁腈(AIBN)引发丙烯酸聚合,利用提拉法在载玻片表面制备了纳米TiO2薄膜;采用热分析仪考察了纳米TiO2胶体颗粒中有机物的热解行为,并用X射线衍射仪测定了经不同温度下焙烧后的纳米TiO2粉体的晶体结构;采用原子力显微镜和透射电子显微镜观察分析了薄膜的微观结构;在对不同制备条件下制备的纳米TiO2干胶进行红外光谱分析的基础上,初步考察了薄膜成膜机理 结果表明,所制备的TiO2薄膜经400℃烧结处理后形成连续、片状。

Enhancing performance of low-temperature processed CsPbI2Br all-inorganic perovskite solar cells using polyethylene oxide-modified TiO_(2)

CsPbX_(3)-based(X=I,Br,Cl)inorganic perovskite solar cells(PSCs)prepared by low-temperature process have attracted much attention because of their low cost and excellent thermal stability.However,the high trap state density and serious charge recombination between low-temperature processed TiO_(2)film and inorganic perovskite layer interface seriously restrict the performance of all-inorganic PSCs.Here a thin polyethylene oxide(PEO)layer is employed to modify TiO_(2)film to passivate traps and promote carrier collection.The impacts of PEO layer on microstructure and photoelectric characteristics of TiO_(2)film and related devices are systematically studied.Characterization results suggest that PEO modification can reduce the surface roughness of TiO_(2)film,decrease its average surface potential,and passivate trap states.At optimal conditions,the champion efficiency of CsPbI_(2)Br PSCs with PEO-modified TiO_(2)(PEO-PSCs)has been improved to 11.24%from 9.03%of reference PSCs.Moreover,the hysteresis behavior and charge recombination have been suppressed in PEO-PSCs.