Synthesis and characterization of novel InVO<Subscript>4</Subscript>–TiO<Subscript>2</Subscript> thin films using the low temperature sol

The InVO₄ sol was obtained by a mild hydrothermal treatment (the precursor precipitation solution at 423 K, for 4 h). Novel visible-light activated photocatalytic InVO₄–TiO₂ thin films were synthesized through a sol–gel dipping method from the composite sol, which was obtained by mixing the low temperature InVO₄ sol and TiO₂ sol. The photocatalytic activities of the new InVO₄–TiO₂ thin films under visible light irradiation were investigated by the photocatalytic discoloration of methyl orange aqueous solution. The thin films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and UV–Vis absorption spectroscopy (UV–Vis). The results revealed that the InVO₄ doped thin films enhanced the methyl orange degradation rate under visible light irradiation, 3.0 wt% InVO₄–TiO₂ thin films reaching 80.1% after irradiated for 15 h.     

Plasmon-resonance-enhanced visible-light photocatalytic activity of Ag quantum dots/TiO2 microspheres for methyl orange degradation

We successfully prepared Ag quantum dots modified TiO₂ microspheres by facile solvothermal and calcination method. The as-prepared Ag quantum dots/TiO₂ microspheres were characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy. The Ag quantum dots/TiO₂ photocatalyst showed excellent visible light absorption and efficient photocatalytic activity for methyl orange degradation. And the sample with the molar ratio of 0.05 (Ag to Ti) showed the best visible light photocatalytic activity for methyl orange degradation, mainly because of the surface plasmon resonance (SPR) effects of Ag quantum dots to generate electron and hole pairs for enhanced visible light photocatalysis. Finally, possible visible light photocatalytic mechanism of Ag quantum dots/TiO₂ microspheres for methyl orange degradation was proposed in detail.     

Ag@AgI等离子体负载TiO2酸蚀纳米带的制备及可见光光催化性能的研究

采用沉积-沉淀法将AgI分散到TiO2酸蚀纳米带上,然后通过光照进而分解出Ag颗粒,最终获得了Ag@AgI等离子体负载的TiO2酸蚀纳米带(AIST)。利用UV-Vis吸收光谱、XRD、SEM对产物进行表征,并研究了可见光下对甲基橙(MO)的光催化降解性能。结果表明,纳米带酸蚀后利于AgI的沉积,Ag的表面等离子体共振效应可以增强催化剂对于可见光的吸收,使可见光下AIST的光催化降解性能显著提高。     

Formation and performances of porous InVO4 films

Porous complex oxide films consisting of preferentially orientated orthorhombic phase of InVO₄ have been prepared using a novel simple method by pyrolysis of amorphous complex precursor. The formation and controlling of porous InVO₄ films can be easily obtained by modifying the calcination temperature. The pure orthorhombic InVO₄ phase can be obtained at a relatively lower temperature (500 °C), and the films are preferential orientation of the (200) face parallel to the substrate. The phase separation mechanism was suggested for the formation of porous films. Under visible light irradiation (λ>400 nm), porous InVO₄ films have shown the photocatalytic activity for photodegradation of gaseous formaldehyde, and can generate photocurrent. The electrochemical properties of the films with different crystal structure and pore structure were also investigated.     

Preparation of novel visible-light-driven In<Subscript>2</Subscript>O<Subscript>3</Subscript>–CaIn<Subscript>2</Subscript>O<Subscript>4</Subscript> composite photocatalyst by sol–gel method

Novel visible-light-activated In₂O₃–CaIn₂O₄ photocatalysts were developed in this paper through a sol–gel method. The photocatalytic activities of In₂O₃–CaIn₂O₄ composite photocatalysts were investigated based on the decomposition of methyl orange under visible light irradiation (λ > 400 nm). The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrum (EDS), X-ray photoelectron spectroscopy (XPS) and UV–vis diffused reflectance spectroscopy (DRS). The results revealed that the In₂O₃–CaIn₂O₄ composite samples with different In₂O₃ and CaIn₂O₄ content can be obtained by controlling the synthesis temperature, and the composite photocatalysts extended the light absorption spectrum toward the visible region. The photocatalytic tests indicated that the composite samples demonstrated high visible-light activity for decomposition of methyl orange. The significant enhancement in the In₂O₃–CaIn₂O₄ photo-activity under visible light irradiation can be ascribed to the efficient separation of photo-generated carriers in the In₂O₃ and CaIn₂O₄ coupling semiconductors.     

Studies on photocatalytic activity of Ag/TiO2 films

Ag/TiO₂ photocatalytic films were produced by hybrid sol-gel method. The photocatalytic degradation of methyl orange (MO) in aqueous solution under 365 nm irradiation on TiO₂ and Ag/TiO₂ thin films was investigated. The state and amount of Ag species within the film and the enhancement mechanism of photocatalytic activity of Ag/TiO₂ were discussed. With a loading molar ratio of Ag/Ti = 0.135 in TiO₂ film, the maximum catalytic efficiency was observed. __________ Translated from Journal of Beijing Normal University (Natural Sciences), 2005, 41(6) (in Chinese)     

三维有序大孔Ag/ZrO2-TiO2：制备及紫外光催化降解染料和水杨酸性能

采用聚苯乙烯(PS)微球作为模板剂,经溶胶-凝胶及煅烧后处理的方法制备了三维有序大孔(3DOM)复合材料Ag/ZrO2-TiO2。通过FTIR、XRD、XPS、N2吸附-脱附和SEM-EDS等对其进行了表征。结果显示,经PS微球作用后的复合材料Ag/ZrO2-TiO2具有锐钛矿晶型结构,其Ag以单质形式存在。该复合材料的孔结构高度有序,属三维有序大孔,平均孔直径为120 nm,孔壁由紧密堆积的Ag/ZrO2-TiO2纳米晶粒组成,孔收缩率约为40%。该复合材料表现出较好的紫外光催化降解水杨酸和甲基橙等染料性能,其活性明显高于商用光催化剂(Degussa P-25)、Ag/ZrO2-TiO2和3DOM ZrO2-TiO2,在90 min内对甲基橙的降解率达80.1%。     

纳米Ag@AgBr表面敏化K_2Ti_4O_9可见光催化剂的微波合成、表征和光催化活性(英文)

利用微波法合成纳米尺寸Ag@AgBr表面敏化K2Ti4O9的复合光催化剂(Ag@AgBr/K2Ti4O9),并通过SEM、X-射线能量色散谱(EDX)、TEM、选定区域电子衍射(SAED)、XRD、紫外-可见漫反射(UV-VisDiffuseReflectance)、XPS等对其进行了表征,同时在可见光下测定催化剂对有机物降解的光催化活性。结果表明,粒径为0.2~0.5μm的Ag@AgBr均匀分散在K2Ti4O9表面,Ag@AgBr/K2Ti4O9对可见光有很好的吸收且Ag@AgBr的担载量影响可见光的吸收。当Ag@AgBr的担载量为25wt%时,复合光催化剂具有最高的光催化活性,光照1h对罗丹明B(RhB)的降解率可达97%。另外,催化剂的担载量和稳定性也做了考察。催化剂较高的光催化活性主要归因于Ag纳米粒子的表面等离子体效应和有效的光生电子-空穴的分离。     

纳米Ag@AgBr表面敏化K2Ti4O9可见光催化剂的微波合成、表征和光催化活性

利用微波法合成纳米尺寸Ag@AgBr表面敏化K₂Ti₄O₉的复合光催化剂（Ag@AgBr/K₂Ti₄O₉）,并通过SEM、X-射线能量色散谱（EDX）、TEM、选定区域电子衍射（SAED）、XRD、紫外-可见漫反射（UV-Vis Diffuse Reflectance）、XPS等对其进行了表征,同时在可见光下测定催化剂对有机物降解的光催化活性。结果表明,粒径为0.2~0.5μm的Ag@AgBr均匀分散在K₂Ti₄O₉表面,Ag@AgBr/K₂Ti₄O₉对可见光有很好的吸收且Ag@AgBr的担载量影响可见光的吸收。当Ag@AgBr的担载量为25wt%时,复合光催化剂具有最高的光催化活性,光照1h对罗丹明B（RhB）的降解率可达97%。另外,催化剂的担载量和稳定性也做了考察。催化剂较高的光催化活性主要归因于Ag纳米粒子的表面等离子体效应和有效的光生电子-空穴的分离。     

Influence of NH<Subscript>3</Subscript>-treating temperature on visible light photocatalytic activity of N-doped P<Subscript>25</Subscript>-TiO<Subscript>2</Subscript>

The influence of NH₃-treating temperature on the visible light photocatalytic activity of N-doped P₂₅-TiO₂ as well as the relationship between the surface composition structure of TiO₂ and its visible light photocatalytic activity were investigated. The results showed that N-doped P₂₅-TiO₂ treated at 600°C had the highest activity. The structure of P₂₅-TiO₂ was converted from anatase to rutile at 700°C. Moreover, no N-doping was detected at the surface of P₂₅-TiO₂. There was no simply linear relationship between the visible light photocatalytic activity and the concentration of doped nitrogen, and visible light absorption. The visible light photocatalytic activity of N-doped P₂₅-TiO₂ was mainly influenced by the synergistic action of the following factors: (i) the formation of the single-electron-trapped oxygen vacancies (denoted as V_o^·); (ii) the doped nitrogen on the surface of TiO₂; (iii) the anatase TiO₂ structure.     

Improved Photocatalytic Activity and Stability of Nano‐sized Ag/Ag2CO3 Plasmonic Photocatalyst by Surface Modification of Fe(III) Nanocluster

The surface modification of Ag/Ag₂CO₃ with Fe(III) ions has been achieved through simply photoreduction‐impregnation method. The obtained products were characterized by means of X‐ray diffraction (XRD), scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), and UV‐vis absorption spectroscopy. Under visible‐light irradiation (γ>420 nm), the Fe(III)/Ag/Ag₂CO₃ sample displays a higher photocatalytic activity and stability than pure Ag₂CO₃ and Ag/Ag₂CO₃ samples for the degradation of methyl orange (MO). The improved photocatalytic activity and stability of this ternary system could be ascribed to the synergetic effect between Ag nanoparticles and Fe(III) nanocluster. The metallic Ag nanoparticles cause an obviously enhanced visible‐light absorption to produce more photogenerated charges, while the Fe(III) works as an active site for the following oxygen reduction to reduce the recombination rate of photogenerated electrons and holes.     

MoS_2/g-C_3N_4复合材料的制备及可见光催化性能

首先在N-甲基吡咯烷酮溶液中超声剥离得到少层的MoS_2,将其与石墨相氮化碳(g-C_3N_4)复合,制得MoS_2/g-C_3N_4复合材料。采用X射线衍射(XRD),扫描电镜(SEM),X射线光电子能谱(XPS),傅里叶变换红外光谱(FTIR),Raman光谱,紫外-可见漫反射吸收光谱(DRS)和光致荧光(PL)技术对复合材料进行表征。可见光下考察MoS_2/g-C_3N_4复合材料光催化降解罗丹明B(Rh B)的活性,结果表明:将少量MoS_2与g-C_3N_4复合可明显提高光催化活性,且1%(w/w)MoS_2/g-C_3N_4复合物的光催化活性最高,可能的原因是MoS_2和g-C_3N_4匹配的能带结构,增大了界面间电荷的传输,降低了光生电子-空穴的复合,进而提高了光催化活性。     

MoS2/g-C3N4复合材料的制备及可见光催化性能

首先在N-甲基吡咯烷酮溶液中超声剥离得到少层的MoS₂,将其与石墨相氮化碳（g-C₃N₄）复合,制得MoS₂/g-C₃N₄复合材料。采用X射线衍射（XRD）,扫描电镜（SEM）,X射线光电子能谱（XPS）,傅里叶变换红外光谱（FTIR）,Raman光谱,紫外-可见漫反射吸收光谱（DRS）和光致荧光（PL）技术对复合材料进行表征。可见光下考察MoS₂/g-C₃N₄复合材料光催化降解罗丹明B（RhB）的活性,结果表明：将少量MoS₂与g-C₃N₄复合可明显提高光催化活性,且1%（w/w）MoS₂/g-C₃N₄复合物的光催化活性最高,可能的原因是MoS₂和g-C₃N₄匹配的能带结构,增大了界面间电荷的传输,降低了光生电子-空穴的复合,进而提高了光催化活性。     

Characterization and activity of visible-light-driven TiO2 photocatalyst codoped with nitrogen and cerium

Nitrogen and cerium codoped TiO₂ photocatalysts were prepared by a modified sol-gel process with doping precursors of cerium nitrate and urea, and characterized by X-ray diffraction (XRD), thermogravimetry-differential scanning calorimetry (TG-DSC), X-ray photoelectron spectra (XPS) and ultraviolet-visible light diffuse reflectance spectra (UV-vis DRS). Results indicate that anatase TiO₂ is the dominant crystalline type in as-prepared samples, and CeO₂ crystallites appear as the doping ratio of Ce/Ti reaches to 3.0 at%. The TiO₂ starts to transform from amorphous phase to anatase at 987.1 K during calcination, according to the TG-DSC curves. The XPS show that three major metal ions of Ce³⁺, Ce⁴⁺, Ti⁴⁺ and one minor metal ion of Ti³⁺ coexist on the surface. The codoped TiO₂ exhibits significant absorption within the range of 400-500 nm compared to the non-doped and only nitrogen-doped TiO₂. The enhanced photocatalytic activity of the codoped TiO₂ is demonstrated through degradation of methyl orange under visible light irradiation.     

Visible-light photocatalytic activity of the metastable Bi20TiO32 synthesized by a high-temperature quenching method

Metastable Bi₂₀TiO₃₂ samples were synthesized by a high-temperature quenching method using α-Bi₂O₃ and anatase TiO₂ as raw materials. The photocatalytic activity of the as-prepared samples was measured with the photodegradation of methyl orange at room temperature under visible light irradiation. The Bi₂₀TiO₃₂ samples exhibited good absorption in the visible light region with a band gap of about 2.38 eV and the band structure of Bi₂₀TiO₃₂ was studied. Photodegradation against methyl orange was much better than α-Bi₂O₃ prepared by the same way. The photocatalytic activity of Bi₂₀TiO₃₂ samples is supposed to be associated with the hybridized Bi 6s and O 2p orbitals. In addition, the dispersive characteristic of Bi 6s orbital in the hybridized valence band facilitates the mobility of the photogenerated carriers and hampers their recombination.     

Synthesis, characterization, and photocatalytic properties of InVO4 nanoparticles

Nanosized InVO₄ with orthorhombic structure was successfully synthesized at a relatively low calcination temperature of 600 °C by using an amorphous heteronuclear complex as precursor. The photocatalytic activity of InVO₄ catalyst has been evaluated by the decomposition of formaldehyde (FAD) under UV light () and visible light irradiation (). The as-synthesized InVO₄ catalyst showed higher photocatalytic activity for the FAD decomposition compared to the sample prepared by the conventional solid-state reaction. The calculations of the electronic band structures indicated that the valence band was composed of the O 2p orbitals, whereas the conduction band was formed by the V 3d orbitals with a small contribution of the In 5s orbitals. The photocatalytic activity of the as-prepared sample is discussed on the basis of the electronic band structure and bulk material structure.     

纳米Fe3O4-TiO2靶向光动力疗法对肝癌细胞的杀伤效应

光动力疗法(PDT)作为一种迅速发展的传统替代疗法,在抗癌治疗中显示出巨大的潜力.为增强靶向性和提高光催化杀伤效率,本研究设计了一种新型光敏剂Fe₃O₄-TiO₂磁性纳米粒.在不同外磁场下,考察其在可见光和紫外光激发下对肝癌细胞的杀伤效应.同时利用流式细胞术检测纳米Fe₃O₄-TiO₂对肝癌细胞凋亡率、细胞周期和线粒体膜电位的影响.根据纳米Fe₃O₄-TiO₂和肝癌细胞的作用方式探讨其抗癌机制.结果表明,可见光激发纳米Fe₃O₄-TiO₂可以杀伤癌细胞,且其杀伤效率与紫外光激发下无明显差别.此外,Fe₃O₄-TiO₂比TiO₂具有更高的细胞摄取率,从而使其具有更高的选择性和光催化杀伤效率.其作用机制是光催化纳米Fe₃O₄-TiO₂产生活性氧ROS抑制癌细胞,然后通过阻滞细胞周期G₀/G₁期,降低线粒体膜电位,线粒体去极化,最终诱导细胞凋亡.     

Effect of dopant concentration on photocatalytic activity of TiO2 film doped by Mn non-uniformly

The thin films of TiO₂ doped by Mn non-uniformly were prepared by sol-gel method under process control. In our preceding study, we investigated in detail, the effect of doping mode on the photocatalytic activity of TiO₂ films showing that Mn non-uniform doping can greatly enhance the activity. In this study we looked at the effect of doping concentration on the photocatalytic activity of the TiO₂ films. In this paper, the thin films were characterized by UV-vis spectrophotometer and electrochemical workstation. The activity of the photocatalyst was also evaluated by photocatalytic degradation rate of aqueous methyl orange under UV radiation. The results illustrate that the TiO₂ thin film doped by Mn non-uniformly at the optimal dopant concentration (0.7 at %) is of the highest activity, and on the contrary, the activity of those doped uniformly is decreased. As a comparison, in 80 min, the degradation rate of methyl orange is 62 %, 12 % and 34 % for Mn non-uniform doping film (0.7 at %), the uniform doping film (0.7 at %) and pure titanium dioxide film, respectively. We have seen that, for the doping and the pure TiO₂ films, the stronger signals of open circuit potential and transient photocurrent, the better photocatalytic activity. We also discusse the effect of dopant concentration on the photocatalytic activity of the TiO₂ films in terms of effective separation of the photon-generated carriers in the semiconductor.     

Ag/Ag2MoO4/Bi2MoO6复合光催化剂的制备及其光催化性能

采用水热、化学沉积和原位光还原的方法成功制备了新型Ag/Ag₂MoO₄/Bi₂MoO₆三元复合光催化剂。通过X射线粉末衍射（XRD）、扫描电子显微镜（SEM）、X射线光电子能谱（XPS）和紫外可见漫反射光谱（UV-Vis DRS）等技术对材料的组成、形貌、光吸收特性和光电化学性能等进行系统分析。以四环素为目标污染物,研究Ag/Ag₂MoO₄/Bi₂MoO₆在可见光下的光催化性能。研究结果表明,相比于纯Ag₂MoO₄和Bi₂MoO₆,Ag的表面等离子体共振（SPR）效应显著拓宽了催化体系对可见光的吸收能力及响应范围。当Ag₂MoO₄理论负载量（质量分数）为24.6%时,Ag/Ag₂MoO₄/Bi₂MoO₆复合材料在20 min内可将四环素完全降解,且5次循环使用后仍保持较高的催化活性,表现出良好的循环稳定性。     

可见光高催化活性GO/Ag3PO4/Ni复合薄膜的制备和性能

以磷酸铵和氧化石墨烯悬浊液的混合液为电解液,采用电化学共沉积法制备了Ag3PO4基GO/Ag3PO4/Ni复合薄膜。运用扫描电子显微镜(SEM)、能量色散谱(EDS)、X射线衍射(XRD)、拉曼光谱(Raman)和紫外可见漫反射光谱(UV-Vis DRS)等对其形貌、物相和光谱特性进行分析。最佳工艺制备的GO/Ag3PO4/Ni复合薄膜呈现出GO包覆在直径为100 nm左右的Ag3PO4纳米球外的表面形貌。GO片与Ag3PO4纳米球之间存在强电荷相互作用。与单独的Ag3PO4纳米球相比,GO片的附着导致带隙缩小,可见光区的吸收率增强。可见光下考察了复合薄膜降解罗丹明B的光催化活性和稳定性,并利用荧光光谱和捕获剂法对薄膜的光催化机理进行了探索。结果表明,GO片的加入不仅显著提高了Ag3PO4的光催化活性,而且提高了Ag3PO4的结构稳定性。光催化降解罗丹明B 60 min时,GO/Ag3PO4/Ni复合薄膜的降解率是Ag3PO4/Ni薄膜的1.32倍。在保持薄膜光催化活性基本不变的前提下可循环使用7次。GO优异的电荷传导性能,以及Ag3PO4纳米球与GO片之间的正协同效应是提高复合薄膜光催化性能的主要原因。