具有主导晶面的BiOIO3/BiOCl异质结制备与光催化性能

分别以乙二醇/去离子水为溶剂,通过溶剂热/水热法分别制备了具有不同主导晶面的BiOIO₃/{110}BiOCl和BiOIO₃/{001}BiOCl异质结。采用X射线衍射、扫描电子显微镜、能量色散谱和紫外可见漫反射光谱对制备的BiOIO₃/BiOCl光催化剂进行了表征。在可见光照射下,通过对罗丹明B和苯酚水溶液的光催化降解,考察了BiOIO₃/BiOCl异质结的光催化活性。结果显示25%BiOIO₃/{110}BiOCl异质结具有最高的光催化效率。BiOIO₃/{110}BiOCl较好的光催化性能是由于其在可见光区较强的光吸收,以及异质结结构和BiOCl所具有的(110)主导晶面有利于光生载流子的分离。超氧自由基(·O₂^-)和空穴(h⁺)是光催化过程中的主要活性物质。此外,根据实验结果探讨了光催化性能增强的机理。     

Synthesis,properties and mechanism of photodegradation of core–shell structured upconversion luminescent NaYF4:Yb3+,Er3+@BiOCl

Microspherical bismuth oxychloride (BiOCl) can only utilize ultraviolet (UV) light to promote photocatalytic reactions. To overcome this limitation, a uniform and thin BiOCl nanosheet was synthesized with a particle size of about 200 nm. As results of UV–visible diffuse reflectance spectroscopy showed, the band gap of this nanostructure was reduced to 2.78 eV, indicating that the BiOCl nanosheet could absorb and utilize visible light. Furthermore, the upconversion material NaYF₄ doped with rare earth ions Yb³⁺ and Er³⁺ emitted visible light at 410 nm following excitation with near‐infrared (NIR) light (980 nm), which could be utilized by BiOCl to produce a photocatalytic reaction. To produce a high‐efficiency photocatalyst (NaYF₄:Yb³⁺,Er³⁺@BiOCl), BiOCl‐loaded NaYF₄:Yb³⁺,Er³⁺ was successfully synthesized via a simple two‐step hydrothermal method. The as‐synthesized material was confirmed using X‐ray diffraction, scanning electron microscopy, X‐ray photoelectron spectroscopy as well as other characterizations. The removal ratio of methylene blue by NaYF₄:Yb³⁺,Er³⁺@BiOCl was much higher than that of BiOCl alone. Recycling experiments verified the stability of NaYF₄:Yb³⁺,Er³⁺@BiOCl, which demonstrated excellent adsorption, strong visible‐light absorption and high electron–hole separation efficiency. Such properties are expected to be useful in practical applications, and a further understanding of the NIR‐light‐responsive photocatalytic mechanism of this new catalytic material would be conducive to improving its structural design and function.     

具有主导晶面的BiOIO3/BiOCl异质结制备与光催化性能

分别以乙二醇/去离子水为溶剂,通过溶剂热/水热法分别制备了具有不同主导晶面的BiOIO₃/{110}BiOCl和BiOIO₃/{001}BiOCl异质结。采用X射线衍射、扫描电子显微镜、能量色散谱和紫外可见漫反射光谱对制备的BiOIO₃/BiOCl光催化剂进行了表征。在可见光照射下,通过对罗丹明 B和苯酚水溶液的光催化降解,考察了 BiOIO₃/BiOCl异质结的光催化活性。结果显示25% BiOIO₃/{110}BiOCl异质结具有最高的光催化效率。BiOIO₃/{110}BiOCl较好的光催化性能是由于其在可见光区较强的光吸收,以及异质结结构和BiOCl所具有的(110)主导晶面有利于光生载流子的分离。超氧自由基(·O₂^-)和空穴(h⁺)是光催化过程中的主要活性物质。此外,根据实验结果探讨了光催化性能增强的机理。     

Preparation and measurement of properties of BiOBr/BiOCl/PANI ternary nanocomposite for highly efficient visible light photocatalytic applications

In this paper, we report the synthesis of the BiOBr/BiOCl/PANI ternary nanocomposite using a simple co-precipitation method. The modified photocatalyst produced was characterized by the FT-IR, FE-SEM equipped with EDS (as a Map), TEM, XRD, PL, Raman, and UV–Vis DRS analytical techniques. The synergetic effect of PANI and surface defects in nanoplates can prolong the recombination rate of photo-generated charge carriers. Thus, photocatalytic and photoelectrochemical activities of samples have been studied. Then, the methyl orange (MO) degradation performance of PANI/BiOBr and BiOBr/BiOCl/PANI was investigated under visible light irradiation. The lamp used to simulate sunlight in this photocatalytic study process was power down white light (5-W LED), less reported. The results got exhibited that the as-prepared BiOBr/BiOCl/PANI (90:10, Bi:PANI) nanocomposite showed a higher photocatalytic efficiency. Based on the scavenger tests, ^·O₂^? played a significant role in the degradation of MO. The connection between BiOBr, BiOCl, and PANI improved photocatalytic activity, which enhanced migration rate of the photo-generated electrons besides limiting the recombination of photo-generated electron–hole pairs.

     

Room Temperature Synthesis and Photocatalytic Activity of Magnetically Recoverable Fe3O4/BiOCl Nanocomposite Photocatalysts

Magnetically recoverable Fe₃O₄/BiOCl nanocomposite photocatalysts were fabricated by a simple chemical coprecipitation method at room temperature. The amount of Fe₃O₄ incorporated into BiOCl was varied from 0 to 20 wt%. The as-synthesized samples were characterized by X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, UV–Vis diffuse reflectance spectroscopy, and vibrating sample magnetometer. The obtained results show that the as-synthesized samples mainly contain both crystalline phases (Fe₃O₄ and BiOCl) and are composed of flower-like nanostructures. Compared to UV light-responsive BiOCl, all the nanocomposite photocatalysts show a strong light absorbance in the range of 250–800 nm, demonstrating that the Fe₃O₄/BiOCl nanocomposites can respond to visible as well as UV light. Moreover, visible light absorbance was increased with the increase in the Fe₃O₄ amount in the composite. The photocatalytic activity of nanocomposite photocatalysts was evaluated by the photodegradation of Rhodamine B (RhB) over the samples under visible light irradiation. The 10 wt% Fe₃O₄/BiOCl nanocomposite photocatalyst shows the highest photocatalytic efficiency among the samples. The Fe₃O₄/BiOCl nanocomposite photocatalyst was stable under visible light irradiation to efficiently degrade RhB molecules after five cycles and could be easily recovered with a magnet after each cycle.     

盐酸溶液处理钒酸铋增强可见光催化活性及其机理

采用盐酸水溶液处理BiVO₄ 的方法获得增强的光催化活性. 在0.1 mol·L^-1 酸溶液中浸渍反应6 h,BiVO₄ 的可见光催化降解苯酚的活性提高了3.5 倍. 采用X 射线衍射(XRD), 扫描电镜(TEM)和漫反射光谱(DRS)等表征手段研究处理后样品的晶相组成和表面形貌, 结合不同酸和氯化物处理的对照实验, 结果表明,在H⁺和Cl^-的协同作用下, BiVO₄表面部分溶出并以BiOCl 沉积, 形成了表面具有凹陷沟壑的BiVO₄颗粒与片状结构BiOCl 的复合物. 采用悬浮液光电压法测定BiOCl 平带电位, 通过BiVO₄和BiOCl 的能带分析及其混合颗粒的光催化活性测试, 确证二者间不存在颗粒间电子转移效应. 增强的光催化活性主要归因于BiVO₄表面形成了有助于光生电荷迁移的凹凸不平结构. 这种表面处理方法有望成为一种增强半导体化合物光催化活性的有效途径.     

Synthesis,characterization and photocatalytic application of TiO2/magnetic graphene for efficient photodegradation of crystal violet

A magnetized nano‐photocatalyst based on TiO₂/magnetic graphene was developed for efficient photodegradation of crystal violet (CV). Scanning electron microscopy, X‐ray diffraction, energy‐dispersive X‐ray spectroscopy and elemental mapping were used to characterize the prepared magnetic nano‐photocatalyst. The photocatalytic activity of the synthesized magnetic nano‐photocatalyst was evaluated using the decomposition of CV as a model organic pollutant under UV light irradiation. The obtained results showed that TiO₂/magnetic graphene exhibited much higher photocatalytic performance than bare TiO₂. Incorporation of graphene enhanced the activity of the prepared magnetic nano‐photocatalyst. TiO₂/magnetic graphene can be easily separated from an aqueous solution by applying an external magnetic field. Effects of pH, magnetized nano‐photocatalyst dosage, UV light irradiation time, H₂O₂ amount and initial concentration of dye on the photodegradation efficiency were evaluated and optimized. Efficient photodegradation (>98%) of the selected dye under optimized conditions using the synthesized nano‐photocatalyst under UV light irradiation was achieved in 25 min. The prepared magnetic nano‐photocatalyst can be used in a wide pH range (4–10) for degradation of CV. The effects of scavengers, namely methanol (OH^? scavenger), p‐benzoquinone (O₂^?? scavenger) and disodium ethylenediaminetetraacetate (hole scavenger), on CV photodegradation were investigated.     

A comparative study of bismuth-based photocatalysts with titanium dioxide for perfluorooctanoic acid degradation

Bismuth-based material has been broadly studied due to their potential applications in various areas, especially used as promising photocatalysts for the removal of persistent organic pollutants (POPs) and several approaches have been adopted to tailor their features. Herein, the bismuth-based photocatalysts (BiOCl, BiPO₄, BiOPO₄/BiOCl) were synthesized by hydrothermal method and advanced characterization techniques (XRD, SEM, EDS elemental mapping, Raman and UV–vis DRS) were employed to analyze their morphology, crystal structure, and purity of the prepared photocatalysts. These synthesized photocatalysts offered a praiseworthy activity as compared to commercial TiO₂ (P25) for the degradation of model pollutant perfluorooctanoic acid (PFOA) under 254 nm UV light. It was interesting to observe that all synthesized photocatalysts show significant degradation of PFOA and their photocatalytic activity follows the order: bismuth-based catalysts > TiO₂ (P25) > without catalyst. Bismuth-based catalysts degraded the PFOA by almost 99.99% within 45 min while this degradation efficiency was 66.05% with TiO₂ under the same reaction condition. Our work shows that the bismuth-based photocatalysts are promising in PFOA treatment.     

Adsorption factor and photocatalytic degradation of dye-constituent aromatics on the surface of TiO2 in the presence of phosphate anions

The photocatalytic degradation for some kinds of dye-constituent aromatics with TiO₂ in the presence of phosphate anions in aqueous dispersion was investigated under both visible light (λ>480 nm) and UV irradiation. The influences of phosphate anion upon the degradation of organics under these different conditions was revealed by the measurement of point of zero ξ-potential (P _ZC) of TiO₂, UV-VIS spectra, HPLC and LC-MS. The adsorption and photodegradation of some organics, which adsorb on the surface of TiO₂ by a dominating group bearing a positive charge, was enhanced, while that of others, which adsorb on the surface of TiO₂ by a dominating group bearing negative charge, was depressed by the presence of phosphate anions under UV irradiation at the experimental conditions (pH 4.3). It was confirmed that better adsorption of organics on the surface of TiO₂ had an advantage in their photocatalytic degradation under UV irradiation. On the other hand, although the adsorption of rhodamine B (RhB) and methylene Blue (MB) markedly increased, their degradation under visible light irradiation was depressed in the presence of phosphate anions. It is suggested that phosphate anion greatly blocked the electron transfer from excited RhB and MB molecules as RhB and MB molecules predominantly adsorbed on the surface of TiO₂ through the electrostatic interaction with surface adsorbed phosphate anions.     

Template‐free Fabrication of Hierarchical Macro‐/mesoporous N‐doped TiO2/graphene Oxide Composites with Enhanced Visible‐light Photocatalytic Activity

Hierarchical macro‐/mesoporous N‐doped TiO₂/graphene oxide (N‐TiO₂/GO) composites were prepared without using templates by the simple dropwise addition mixed solution of tetrabutyl titanate and ethanol containg graphene oxide (GO) to the ammonia solution, and then calcined at 350 °C. The as‐prepared samples were characterized by scanning electron microscopy (SEM), Brunauer‐Emmett‐Teller (BET) surface area, X‐ray diffraction (XRD), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and UV‐Vis absorption spectroscopy. The photocatalytic activity was evaluated by the photocatalytic degradation of methyl orange in an aqueous solution under visible‐light irradiation. The results show that N‐TiO₂/GO composites exhibited enhanced photocatalytic activity. GO content exhibited an obvious influence on photocatalytic performance, and the optimal GO addition content was 1 wt%. The enhanced photocatalytic activity could be attributed to the synergetic effects of three factors including the improved visible light absorption, the hierarchical macro‐mesoporous structure, and the efficient charge separation by GO.     

Thermal Stability,Microstructure and Photocatalytic Activity of the Bismuth Oxybromide Photocatalyst

Flake BiOBr was first prepared by a solution method at room temperature. Then, the produced BiOBr was calcined at different temperatures. It was found that BiOBr is not a stable compound. It transforms to plate‐like Bi₂₄O₃₁Br₁₁at around 750°C and the formed Bi₂₄O₃₁Br₁₁ can further convert to rod‐like α‐Bi₂O₃ at around 850°C. The prepared compounds were characterized with X‐ray diffraction (XRD), N₂ physical adsorption, scanning electron microscopy (SEM), and UV‐Vis diffuse reflectance spectra (DRS), respectively. The photocatalytic activity of the produced bismuth oxybromides was evaluated by photocatalytic decomposition of acid orange II under both visible light (λ>420 nm) and UV light (λ=365 nm) irradiation. Results show that these compounds have different band gaps and different photocatalytic properties. The band gap energies of the as‐prepared samples were found to be 2.82, 2.79, 2.60 and 3.15 eV for BiOBr, BiOBr/Bi₂₄O₃₁Br, Bi₂₄O₃₁Br, and α‐Bi₂O₃, respectively. Under both UV light and visible light irradiation, the photocatalytic activity follows the order: BiOBr/Bi₂₄O₃₁Br mixture>BiOBr>Bi₂₄O₃₁Br>α‐Bi₂O₃. The change in photocatalytic activity could be attributed to the different light absorption ability and microstructures of the photocatalysts.     

Photocatalytic oxidation of gaseous trichloroethylene by UV/TiO2 process

Summary The objective of this study was to investigate the reaction behavior of the photocatalytic oxidation of gaseous trichloroethylene (TCE) using titanium dioxide at room temperature. The experiments were carried out under various humidity levels and oxygen contents of carrier gas in an annular photoreactor. Experimental results indicated that the factors affecting the photocatalysis of TCE by UV/TiO₂ process are carrier gases and humidity. It was found that increasing the relative humidity in inlet gas flow under low humidity could improve the decomposition of trichloroethylene and the mineralization of organic intermediates at an irradiation UV light intensity of 2.82 W m^-2 by UV/TiO₂ process. The photocatalytic kinetics of gaseous trichloroethylene can be described by the Langmuir-Hinshelwood rate equation.     

Construction of immobilized films photocatalysts with CdS clusters decorated by metal Cd and BiOCl for photocatalytic degradation of tetracycline antibiotics

A kind of CdS/Cd-BiOCl immobilized films photocatalyst was prepared. The optical and physicochemical properties of the CdS/Cd-BiOCl photocatalysts were analysed, and the detailed characterization revealed CdS/Cd-BiOCl films photocatalyst with good charge carrier separation effect. The reusabilities and photocatalytic properties of the samples were studied. The 15%CdS/Cd-BiOCl photocatalyst exhibited superior performance in photocatalytic degradation of tetracycline (TC) and favorable stability under visible light irradiation. As for the photodegradation rate of TC, 15%CdS/Cd-BiOCl exhibited an excellent photodegradation activity, which is 4.06 and 9.53 times higher than that of CdS/Cd and BiOCl, respectively. The results showed that dominant active species are ^?O₂^? and ^?OH radicals during photodegradation. The charge transfer in Z-scheme CdS/Cd-BiOCl films photocatalyst could synchronously generate conduct band (CB) electrons in BiOCl and valence band (VB) holes in CdS, and metal Cd served as electron mediator. This work can be a reference for the design of film photocatalysts and new insight for photodegradating towards contaminants.     

Highly Selective Thiocyanate Electrode Based on Bis‐bebzion Schiff Base Binuclear Copper(II) Complex as Neutral Carrier

Abstract

A highly selective polyvinyl chloride (PVC) membrane electrode, based on N,N′‐(aminoethyl)ethylenediamide bis(2‐benzoideneimine) binuclear copper(II) complex [Cu(II)‐AEBB] as neutral carrier, was prepared for thiocyanate (SCN^?) determination, which displays an anti‐Hofmeister selectivity sequence for a series of anions in the following order: SCN^?>ClO₄ ^?>Sal^? > I^?>NO₃ ^?>Br^?> Cl^?>NO₂ ^?>SO₃ ^2?>F^?>H₂PO₄ ^?>SO₄ ^2?. The electrode exhibited near‐Nernst response for SCN^? with a slope of –59.0 mV/decade over a wide concentration range (8.5×10^?7～6.8×10^?1 mol/L) with a detection limit of –5.0×10^?7 mol/L in pH 5.0 phosphate buffer solution at 25°C. Alternating current (AC) impedance and equivalent circuits were used to investigate the thiocyanate response mechanism of the membrane doped with [Cu(II)‐AEBB].     

MOF-808/BiOCl复合材料的制备及其光催化性能

将高稳定性的MOF-808与BiOCl结合,采用简便的水热法制备出新型MOF-808/BiOCl复合异质结材料。以环丙沙星(CIP)为污染物,探究复合材料MOF-808/BiOCl对CIP的光催化性能。发现含有10% MOF-808的复合材料(MOF-808/BiOCl-10%)表现出最佳的光催化活性。在紫外光照射20 min内,MOF-808/BiOCl-10%对CIP的光催化降解效率高达94.7%。通过X射线粉末衍射、扫描电镜、红外光谱、荧光光谱、紫外可见漫反射光谱、光电流、电化学阻抗等表征技术来考察材料的物相组成、形貌以及光电化学性质。紫外可见漫反射光谱的结果表明,MOF-808/BiOCl-10%材料光吸收范围得到提高。同时进行了自由基捕获实验。基于以上实验数据,提出了MOF-808/BiOCl复合材料可能的光催化机理。     

Photocatalytic degradation of trichloroethylene on platinum ion-doped TiO<Subscript>2</Subscript> under visible light irradiation

Porous platinum ion-doped TiO₂ (Pt–TiO₂) was prepared by a sol–gel method and demonstrated to have superior photocatalytic activity for the photodegradation of gaseous trichloroethylene (TCE) under visible light (VL) irradiation from a xenon lamp equipped with 422-nm cut-off filter. Kinetic studies were performed to clarify the effect of the doping amounts, space times, VL intensity, and mole fractions of TCE, O₂, and H₂O on the degradation of TCE. Under ultraviolet (UV) irradiation, the photocatalytic activity of Pt–TiO₂ was the same as that of TiO₂, indicating that the doped Pt ion did not act as a recombination center for the photogenerated holes and electrons. Based on the kinetic data and reaction products, we conclude that the photocatalytic degradation of TCE on Pt–TiO₂ under VL irradiation proceeds similarly to TiO₂ under UV irradiation. We also performed the photocatalytic degradation of TCE at the space time of 7.5 × 10⁷ g s mol^?1 in a tubular reactor packed with the Pt–TiO₂ pellets which are more suitable than the Pt–TiO₂ powder for the practical remediation of the contaminated gas. TCE was completely degraded, i.e. 100% conversion was achieved under VL irradiation but only a small quantity of CO₂ was formed with the stoichiometric ratio of [CO₂]_formed/[TCE]_degraded of ca. 0.33. By switching the gas stream containing TCE to humid air, more CO₂ was formed, indicating that the dichloroacetates accumulated on the Pt–TiO₂ surface are photodegradable to CO₂ under VL irradiation.     

Synthesis,Characterization, and Photocatalytic Properties of Bismuth (III)‐benzene‐1,3,5‐tricarboxylate

{[Bi(BTC)(H₂O)₂] · H₂O}_n (H₃BTC = 1,3,5‐benzenetricarboxylic acid) was synthesized by an eco‐friendly hydrothermal method and characterized by single‐crystal X‐ray diffraction, IR and UV/Vis spectroscopy, photoluminescence (PL), and thermogravimetric analyses. The complex featured a 3D metal‐organic framework with Bi₂ secondary building units. In the complex, the central Bi³⁺ is nine‐coordinate, three central Bi atoms and three BTC^3– anions are interconnected into a ring with the dimension of 7.95 × 9.89 Ų. Moreover, the complex is decomposed at over 388 °C, showing its highly thermal stability. Further, the complex exhibits photocatalytic activity for the degradation of methyl orange (MO) solution under UV light irradiation, and its structure can keep consistent with the original one after 9 h photocatalytic reaction, indicating that it is also very stable under UV light. Therefore, it could be anticipated the novel coordination complex will be a stable ultraviolet light catalyst.     

溶剂热法制备Ag/TiO2纳米材料及其光催化性能

以乙醇为溶剂, 钛酸四丁酯为前驱体, 用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂. 利用X射线衍射(XRD)、N₂吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征, 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了不同Ag含量样品的光催化性能. 结果表明: 用溶剂热法制备的样品中TiO₂皆为锐钛矿相, 金属Ag颗粒沉积在TiO₂表面, 粒径为2 nm左右, 比表面积较溶胶凝胶法制备的样品大大增加, 最高可达151.44 m²·g^-1; UV-Vis光谱和光催化实验表明: Ag修饰使TiO₂对光的吸收能力大大增强, 吸收带边红移至可见光区, 亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型; 溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品, 在紫外光和可见光下, Ag摩尔分数为5%的样品表现出最佳的光催化活性.     

溶剂热法制备Ag/TiO2纳米材料及其光催化性能

以乙醇为溶剂, 钛酸四丁酯为前驱体, 用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂. 利用X射线衍射(XRD)、N₂吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征, 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了不同Ag含量样品的光催化性能. 结果表明: 用溶剂热法制备的样品中TiO₂皆为锐钛矿相, 金属Ag颗粒沉积在TiO₂表面, 粒径为2 nm左右, 比表面积较溶胶凝胶法制备的样品大大增加, 最高可达151.44 m²·g^-1; UV-Vis光谱和光催化实验表明: Ag修饰使TiO₂对光的吸收能力大大增强, 吸收带边红移至可见光区, 亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型; 溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品, 在紫外光和可见光下, Ag摩尔分数为5%的样品表现出最佳的光催化活性.     

溶剂热法制备Ag/TiO2纳米材料及其光催化性能

以乙醇为溶剂, 钛酸四丁酯为前驱体, 用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂. 利用X射线衍射(XRD)、N₂吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征, 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了不同Ag含量样品的光催化性能. 结果表明: 用溶剂热法制备的样品中TiO₂皆为锐钛矿相, 金属Ag颗粒沉积在TiO₂表面, 粒径为2 nm左右, 比表面积较溶胶凝胶法制备的样品大大增加, 最高可达151.44 m²·g^-1; UV-Vis光谱和光催化实验表明: Ag修饰使TiO₂对光的吸收能力大大增强, 吸收带边红移至可见光区, 亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型; 溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品, 在紫外光和可见光下, Ag摩尔分数为5%的样品表现出最佳的光催化活性.