Chemical-bonds Conjugated SnO_2/AgIO_4 Hybrids for Degradation of High Concentration Rhodamin B under Visible Light Illumination

SnO_2/AgIO_4 hybrids were fabricated by an in-situ synthetic method at room temperature. The structure, morphology, light response range, separation efficiency of the electron-hole pairs and elements of the as-synthesized samples were characterized by adopting X-ray diffraction, scanning electron microscopy, UV-Vis diffuse reflectance spectroscopy, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy, respectively. The synergistically photocatalytic degradation mechanism of the as-synthesized composites was also proposed. The experimental results reveal that under the visible light irradiation the as-synthesized SnO_2/AgIO_4 hybrids can enhance the photocatalytic degradation efficiency of rhodamine B compared to pure samples. With increasing the molar ratios of AgIO_4 to SnO_2, it displays the trend of first increasing and then decreasing. When it is 1:2 in 150 min, the as-prepared hybrids have the highest degradation efficiency of 93.1%, which increases by 6550.0%, 30.5%, and 1505.0% compared to those of pure SnO_2, AgIO_4, and TiO_2(P25), respectively. Moreover, the Sn-O-Ag cross-linking bonds are formed at the interfaces of SnO_2 and AgIO_4. In addition, superoxide anion radicals and holes play a major role in the process of photodegradation.     

In-situ Synthesis of SnO_2 Quantum Dots/ZnS Nanosheets Heterojunction as a Visible-light-driven Photocatalyst for Degradation of Rhodamine B,Potassium Dichromate and Tetracycline

The SnO_2 quantum dots (SnO_2QDs)/ZnS nanosheets (ZnSNs) heterojunction was fabricated via an in-situ synthetic method at room temperature.Rhodamine B,potassium dichromate,and tetracycline were used to discuss the photocatalytic activities of the as-prepared samples under the visible light illumination.The photocatalytic mechanism of the as-prepared samples was also proposed.The experimental results indicate that the degradation efficiency of the as-prepared SnO_2QDs/ZnSNs heterojunction first increases and then decreases with increasing the usage of ZnSNs.When the mass ratio of SnO_2QDs to ZnSNs is 1:2 in 180 min,the as-prepared samples have the highest degradation efficiency of 89.1% for rhodamine B,97.7% for potassium dichromate,and 83.8% for tetracycline,which are much higher than 51.7%,26.8%,and 0.9% of pure SnO_2QDs as well as 37.9%,87.1%,and 19.1% of pure ZnSNs,respectively.After it is repeatedly degraded for 3 times,it possesses the degradation efficiency of 62.5% for rhodamine B,which increases by 200.5% in comparison with 20.8% of the pure SnO_2QDs.Moreover,the enhanced photocatalytic performances of the as-prepared hybrids are attributed to the formation of heterojunction between the SnO_2QDs and ZnSNs.In addition,hydroxyl radicals and superoxide anion radicals play major roles during the photocatalytic degradation process,while holes play a minor role.     

Preparation and Properties of CdS/Spherical g-C_3N_4 n-n Heterojunction as a Visible-Light-Driven Photocatalyst for Tetracycline Degradation

The Cd S/spherical g-C3 N4 n-n heterojunction photocatalyst was fabricated via a solvothermal method. The tetracycline was used to characterize the photocatalytic properties of the as-developed hybrids. The photocatalytic degradation mechanism of the as-developed heterojunction photocatalyst was also analyzed. Research results show that Cd S nanoparticles are well dispersed in the surface layer of spherical g-C_3 N_4. Moreover, the mass ratio of Cd S to spherical g-C_3 N_4 will influence the photocatalytic activity of the asdeveloped composites, which shows the trend of first increasing and then decreasing as it increased. When the mass ratio is 7:1, in 25 min, the as-developed heterojunction shows 93.2 % of the maximum photocatalytic efficiency and still exhibits 83.6 % after 5 times cycle testing. Moreover, the as-developed hybrids can accelerate the electron transport and improve the separation efficiency of photo-generated carriers compared with pure samples. In addition, the holes and superoxide radicals are dominating active species during the photocatalytic degradation process.     

Visible-Light-Sensitive SrCO_3/AgI Hybrids for Tetracycline Degradation

The SrCO_3/AgI photocatalysts were prepared via a co-precipitation method by using SrCO_3 as a co-photocatalyst and AgI as a photo sensitizer.X-ray diffraction,field emission scanning electron microscope,X-ray photoelectron spectrometer,UV-vis diffuse reflectance spectroscopy and electrochemical impedance spectroscope were used to analyze the structure,micro-morphology,chemical compositions,optical properties and photo-generated carrier behaviors of the as-prepared samples,respectively.The photocatalytic degradation mechanism of the as-developed composites was also proposed.Analysis results show SrCO_3,an insulator,can improve the photocatalytic performances and recyclability of AgI for degrading tetracycline under visible light.As the theoretical molar ratio of Sr(NO_3)_2 to AgNO_3 increases,the degradation efficiency of the hybrids first increases and then descends.When the theoretical molar ratio of that is 1:1,it acquires the maximum of 66.6% within 8 min.This is higher than 32.0% of pure AgI and 34.0% of SrCO_3.Moreover,after three times degradations it is 63.0%,which is higher than 13.6% of AgI.The improvement of the photocatalytic performance of the sample is attributed to the construction of hybrids.The main activated species in catalysis process are superoxide radicals.     

石墨烯／二氧化钛复合光催化剂的制备及可见光催化性能研究

以钛酸正丁酯为钛源,采用一种简单的原位水解技术制备了石墨烯／二氧化钛复合光催化剂．通过XRD、SEM、TEM、Raman、PL和UV-vis光谱仪等分析手段对产物进行了表征,并测试了该复合光催化剂在可见光区对染料罗丹明B的光催化降解性能．实验结果表明：制备的复合光催化剂主晶相为锐钛矿型二氧化钛,石墨烯表面富集的二氧化钛颗粒尺寸约为10-20nm左右,均匀弥散、形成一层致密的氧化钛膜层．样品降解罗丹明B测试结果表明,石墨烯与二氧化钛的复合,一方面使得二氧化钛光催化剂在可见光区的吸收大大增强,另外,石墨烯的存在能够促进二氧化钛半导体中电子和空穴的有效分离,并且在一定程度上提高了污染物在半导体表面的富集效率,从而使石墨烯／二氧化钛复合光催化剂对降解罗丹明B表现出良好的光催化活性．     

ZnO/g-C3N4光催化剂在微流控芯片中的光催化性能

采用浸渍法合成ZnO质量分数不同的ZnO/g-C₃N₄复合光催化剂,分析样品的结构、形态、化学组成和光学性能等. 将制备好的样品固定到微流控芯片中,降解不同的染料（亚甲基蓝、中性红、孔雀石绿、罗丹明B）,评价样品在可见光下的光催化性能. 样品的表征结果表明,在ZnO/g-C₃N₄复合物中,ZnO、g-C₃N₄间存在相互作用,ZnO/g-C₃N₄复合物对可见光的利用更为充分;与g-C₃N₄相比,在ZnO/g-C₃N₄复合物中光生电子-空穴对的复合明显被抑制. 光催化实验结果表明,6 % ZnO/g-C₃N₄具有最佳光催化性能,在光照强度为60 klx,液体流速为20 μL/min时,其对罗丹明B溶液的降解效率为98.9%.多次循环后的光催化降解亚甲基蓝性能研究表明,样品在微流控芯片中进行光催化降解实验具有稳定性和可靠性.     

Highly Efficient Removal of Organic Dyes by Novel As-synthesized AgBr/montmorillonite Composite

A facile deposition method has been developed for large-scale synthesis of visible-light-driven AgBr/montmorillonite composite catalyst for the first time. The as-synthesized samples were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), Fourier transform infrared spectroscopy(FT-IR), transmission electron microscopy(TEM), UV-vis diffuse reflectance spectroscopy(UV-vis DRS) and Brunauer-Emmett-Teller(BET) surface area analysis, respectively. Through the combined action of adsorption and photodegradation, the as-prepared AgBr/montmorillonite composite exhibited a higher removal efficiency for rhodamine B(RhB) than that of Na-montmorillonite and AgBr. For the methyl orange(MO) removal, the AgBr/montmorillonite composite possessed a superior photocatalytic performance compared with Namontmorillonite and AgBr. The enhanced photocatalytic activity of AgBr/montmorillonite composite can be attributed to the effective separation of the electron-hole pairs. In AgBr/montmorillonite suspension, the superoxide radicals are the main reactive oxygen species for dye degradation under visible light illumination.     

Gd掺杂BiVO4纳米粉体的制备及其光催化性能

采用水热法制备了单斜相白钨矿结构的Gd掺杂BiVO4粉体。采用X-射线粉末衍射、扫描电子显微镜和紫外一可见吸收光谱对样品进行表征。研究了不同浓度Gd掺杂BiVO4纳米粉体的晶相组成、形貌和光催化性能的影响。结果表明,Gd掺杂BiVOt粉体在可见光下的催化活性优于纯相BiVO4粉体,Gd掺杂量为2％的样品对罗丹明B催化效果最佳,在100min内对罗丹明B溶液的分解率达98％。     

Magnetically Recoverable PEI/Titanate@Fe_3O_4 Photocatalysts: Fabrication and Photocatalytic Properties

The magnetically separable ternary polyetherimide/titanate@Fe_3 O_4(PTF) photocatalysts of special heterostructure between magnetite(Fe_3 O_4) microspheres and titanates nanosheets modified by polyetherimide(PEI) were successfully fabricated via a simple facile hydrothermal deposition method. The as-prepared photocatalysts were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, Transmission electron microscopy and UV-vis diffuse reflectance spectroscopy etc. The results showed that the as-fabricated material had a structure of Fe_3 O_4 microspheres coated with titanates nanosheets modified by PEI. The special interfacial contact between 3 D microsphere and 2 D nanosheets in the nanoarchitectures was formed via electrostatic attraction. Furthermore, the resulted photocatalysts were tested by degradation reaction of methylene blue under visible light irradiation and demonstrated an enhanced performance than the pure Fe_3 O_4 microspheres, and the photocatalytic activity enhanced with the molar ratio of Fe_3 O_4 microspheres and modified titanate gradually, which was attributed to the expansion of the surface area and the different electrostatic contact between the Fe_3 O_4 microspheres and titanate nanosheets. Moreover, the obtained results revealed the high yield magnetic separation and efficient reusability of PTF-5(96.7%) over 3 times reuse.     

Degradation of Formaldehyde and Benzene by TiO_2 Photocatalytic Cement Based Materials

A novel photocatalytic cement based material was prepared. The distribution of TiO_2 on the surface of cement was characterized by scanning electron microscope(SEM) and X-ray diffraction(XRD), which showed the relationship of photocatalysis and presence of TiO_2. TiO_2 also had an impact on cement hydration, which was studied by thermal analysis. With 300 W UV illuminations, formaldehyde and benzene were degraded efficiently by the prepared photocatalytic cement based materials. 15wt% TiO_2/cement showed the highest degradation efficiency and capability. The results show that formaldehyde and benzene can be degraded within 4 and 9 hours, respectively. Besides, inorganic ions can induce TiO_2 agglomeration. As a result, the presence of inorganic ions in cement is unfavorable for degradation. The photocatalytic cement based materials were fabricated and the degradation efficiency of formaldehyde was measured on building roof under sunlight illumination. Formaldehyde in glass chamber can be degraded thoroughly within 10 days.     

Mass Production of Bi_3NbO_7/Bi_2Zn_(2/3)Nb_(4/3)O_7 Composites and Their Visible-light Photocatalytic Activity

Series Bi_3NbO_7/Bi_2Zn_(2/3)Nb_(4/3)O_7 (BN/BZN) composites were synthesized through a facile solid state reaction method. The products were characterized by X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM) and UV-vis diffuse reflectance spectroscopy(DRS). When BN: BZN=0.1 mole ratio, the BN/BZN composite showed the best visible-light-driven photocatalytic performance, which decomposed nearly 100% of Rh B(10 ppm, p H=3-4) within 40 min. The results demonstrated that in-situ solid state synthesis of BN/BZN composites could be an efficient strategy to develop new photocatalyst for environmental remediation.     

Synthesis of novel CaCO_3/Ag_2CO_3/Ag I/Ag plasmonic photocatalyst with enhanced visible light photocatalytic activity.

In this work, novel Ca CO3/Ag2CO3/Ag I/Ag plasmonic photocatalysts were successfully synthesized by a two-step in situ ion exchange process and their photocatalytic properties were studied. The morphology, crystal structure and optical properties of the as-prepared Ca CO3/Ag2CO3/Ag I/Ag nanocomposites were characterized by transmission electron microscopy(TEM), XRay diffraction(XRD), and UV-vis diffuse reflectance spectroscopy. The photocatalytic activity of the obtained nanocomposites was evaluated by the photodegradation of methyl orange(MO) under visible light irradiation. It was found that the as-prepared Ca CO3/Ag2CO3/Ag I/Ag plasmonic photocatalyst exhibits high visible light photocatalytic activity. With an optimized composition, MO dye can be decomposed by more than 94% within 15 min under visible light irradiation. Moreover, the photocatalytic stability could be greatly improved upon the addition of Na2CO3 into the photocatalytic system. From the proposed photocatalytic mechanism, the strong surface plasmon resonance effect of Ag nanoparticles and the efficient separation of photogenerated electrons and holes can effectively enhance the photocatalytic performance of the Ca CO3/Ag2CO3/ Ag I/Ag composites.     

Ag3PO4/GO光催化剂的制备及性能研究

以氧化石墨烯(GO)为基底,利用离子交换法制备了球形和立方体表面结构的Ag₃PO₄/GO复合光催化剂。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和紫外-可见光谱(UV-Vis DRS)对样品进行了表征。罗丹明B的光催化降解实验结果表明：Ag₃PO₄/GO催化剂在100 min内对20 mg/L罗丹明B的去除率可达98.5%,明显高于球形Ag₃PO₄ (83.8%)及立方形Ag₃PO₄ (88.1%)。另外,Ag₃PO₄/GO复合材料在光催化降解重复性实验中表现出良好的稳定性,循环五次后对罗丹明B的去除率仍可达95%以上。     

Ag3PO4/BiPO4复合光催化剂的制备及其降解罗丹明B的研究

采用水热法合成复合Ag₃PO₄/BiPO₄光催化剂,考察不同pH和不同复合比例下合成的光催化剂对溶液中罗丹明B的光催化降解性能,并与BiPO₄进行对比。结果表明:在pH=7,复合比例Ag₃PO₄/BiPO₄摩尔比为4:3条件下水热制备的Ag₃PO₄/BiPO₄对可见光的利用率最高,催化性能最好;降解180 min后,对罗丹明B的降解率达到61%,较纯相BiPO₄提升了27%。本文还利用XRD、SEM和紫外可见漫反射(UV-Vis DRS)等测试手段对合成的样品进行表征,分析得出复合Ag₃PO₄之后,催化剂的禁带宽度变窄,并出现较多的独居石晶型BiPO₄,光生电子与空穴复合效率变低,从而使复合材料的光催化降解罗丹明B的能力得到提升。     

Visible Light-induced Cr-doped SrTiO_3-g-C_3N_4 Composite for Improved Photocatalytic Performance

Novel visible light-induced Cr-doped Sr Ti O3-g-C3N4 composite photocatalysts were synthesized by introducing polymeric g-C3N4. The composite photocatalyst was characterized by X-ray diffraction(XRD), high-resolution transmission electron microscopy(HRTEM), Fourier transform infrared(FT-IR) spectroscopy, UV-vis diffuse reflection spectroscopy, photoluminescence(PL) spectroscopy and BET surface area measurements. The photocatalytic oxidation ability of the novel composite photocatalyst was evaluated using methyl orange(MO) as a target pollutant. The photocatalysts exhibited a significantly enhanced photocatalytic performance in degrading MO. The optimal g-C3N4 content for the photodegradation activity of the composite photocatalysts was determined. The as-prepared composite photocatalyst exhibits an improved photocatalytic activity due to enhancement of photo-generated electron-hole separation at the interface.     

Magnetically Recoverable PEI/Titanate@Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> Photocatalysts: Fabrication and Photocatalytic Properties

The magnetically separable ternary polyetherimide/titanate@Fe₃O₄ (PTF) photocatalysts of special heterostructure between magnetite (Fe₃O₄) microspheres and titanates nanosheets modified by polyetherimide (PEI) were successfully fabricated via a simple facile hydrothermal deposition method. The as-prepared photocatalysts were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, Transmission electron microscopy and UV-vis diffuse reflectance spectroscopy etc. The results showed that the as-fabricated material had a structure of Fe₃O₄ microspheres coated with titanates nanosheets modified by PEI. The special interfacial contact between 3D microsphere and 2D nanosheets in the nanoarchitectures was formed via electrostatic attraction. Furthermore, the resulted photocatalysts were tested by degradation reaction of methylene blue under visible light irradiation and demonstrated an enhanced performance than the pure Fe₃O₄ microspheres, and the photocatalytic activity enhanced with the molar ratio of Fe₃O₄ microspheres and modified titanate gradually, which was attributed to the expansion of the surface area and the different electrostatic contact between the Fe₃O₄ microspheres and titanate nanosheets. Moreover, the obtained results revealed the high yield magnetic separation and efficient reusability of PTF-5 (96.7%) over 3 times reuse.     

Aqueous Sn-S Complex Derived Electron Selective Layer for Perovskite Solar Cells

A novel aqueous Sn-S complex solution was applied as precursor to fabricate SnO_2 electron selective layers (ESLs) for the hybrid perovskite solar cells (PSCs).The tin and sulfur powder were directly dissolved in a (NH_4)_2S water solution to form Sn-S precursor.After depositon and annealing,the SnO_2 film was formed,presenting as a low cost and enviromental friendly method for preparation of ESL.The films showed excellent transmittance at visible wavelength range.Moreover,the method exhibited high compatibility for doping using Cu,Cd,Li,and Zn elements.Zn doping (0.05 M) in the as-prepared SnO_2 ESL significantly improved perovskite solar cells (PSCs) performance.The highest PCE of 13.17% was achived with 15% enhancement compared to that of undoped SnO_2 ESL samples.TiCl_4 modifications on SnO_2 film improved photovoltaic performance to 14.45%,but resulted in the poor long-term stability,around 80% more degredation than that of PSCs based on Zn-doped SnO_2 films.     

聚苯胺插层三氧化钼复合光催化剂的制备及性能

以苯胺柱撑的三氧化钼有机-无机杂化体为反应前躯体,在空气气氛下于120 ℃进行氧化聚合,制备了一种聚苯胺插层MoO₃ 复合材料。以罗丹明B(RhB)为目标降解物,以MoO₃ 复合材料为光催化剂,考察了其催化性能,并研究了光照时间、催化剂质量浓度和pH 与光催化降解效率的关系。结果表明,在pH 为1~4、催化剂的质量浓度为0.30~0.40g/L、光照时间2.0h的条件下,MoO₃/PANI复合材料对罗丹明B具有良好的光降解效果,降解率最高可达98.00%。     

Biomolecule-assisted solvothermal synthesis and enhanced visible light photocatalytic performance of Bi<Subscript>2</Subscript>S<Subscript>3</Subscript>/BiOCl composites

Novel Bi₂S₃/BiOCl photocatalysts were successfully synthesized via a facile biomolecule-assisted solvothermal method and biomolecule L-cysteine was used as the sulfur source. The structures, morphology, and optical properties of the synthesized samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, transmission electron microscopy (TEM), and UV-vis diffuse reflectance spectroscopy (DRS). The presence of Bi₂S₃ in the Bi₂S₃/BiOCl composites could not only improve the optical properties but also enhance the photocatalytic activities for the degradation of Rhodamine B (RhB) under visible-light irradiation (λ > 420 nm) as compared with single Bi₂S₃ and BiOCl. Especially, the sample displayed the best performance of the photodegradation when the feed molar ratio of BiCl3 and L-cysteine was 2.4:1, which was about 10 times greater than that of pure BiOCl. The enhanced photocatalytic activities could be ascribed to the effective separation of photoinduced electrons and holes and the photosensitization of dye. Moreover, the possible photodegradation mechanism was also proposed, and the results revealed that the active holes (h⁺) and superoxide radicals (?O₂ ^?) were the main reactive species during photocatalytic degradation.     

铬银共掺杂改性纳米TiO2光催化剂及其光催化性能研究

以钛酸四丁酯为原料,利用溶胶凝胶法制备了Cr/Ag共掺杂的TiO2纳米材料.采用XRD、SEM、EDS等测试分析技术对掺杂纳米TiO2粉体进行了表征;以甲基橙为降解物,在太阳光照射条件下研究了掺杂对光催化活性的影响.研究结果表明:掺杂后的纳米TiO2的光催化性能明显提高,优于纯TiO2.当共掺杂的比例为Cr 1.0%/Ag 0.5%时,样品的效果最佳,对甲基橙的3h降解率达到97.63%.