Fe3+掺杂TiO2/凹凸棒复合光催化剂的制备和光催化活性

用酸催化溶胶-凝胶法制备了Fe³⁺掺杂TiO₂/凹凸棒（Fe³⁺-TiO₂/ATP）复合光催化剂,对其结构、微观形貌、光吸收性能和可见光下的光催化性能进行了表征。XRD和TEM测试结果表明,Fe³⁺-TiO₂/ATP具有较好的热稳定性,经450 ℃热处理后的ATP晶体结构基本保持不变,锐钛矿TiO2均匀的分布在ATP表面,TiO2颗粒之间无团聚,且平均粒径小于纯TiO₂。UV-Vis-DRS测试结果表明,Fe³⁺的掺杂可明显增强复合光催化剂对可见光的吸收,光响应范围拓展到了整个紫外-可见光区。在可见光下,Fe³⁺-TiO₂/ATP复合光催化剂对亚甲基蓝具有很好的催化降解活性。Fe³⁺-TiO₂/ATP的反应速率常数分别为TiO₂/ATP、P25和纯TiO2的1.37、4.83和6.51倍。复合光催化剂的沉降性能优于纯TiO2和P25,易于分离。     

Ag负载CdMoO4光催化剂的制备及其催化性能

采用硼氢化钠还原法制备了Ag负载CdMoO₄光催化剂。运用X射线粉末衍射（XRD）、扫描电镜（SEM）和透射电镜（TEM）等测试手段对催化剂的组成和结构进行了表征;采用紫外-可见漫反射光谱（UV-Vis DRS）和X射线光电子能谱（XPS）等技术对催化剂的光响应和表面状态进行了分析,考察了不同Ag负载量对CdMoO₄紫外光降解罗丹明B和可见光选择性氧化苯甲醇性能的影响。结果表明,与CdMoO₄相比,Ag/CdMoO₄具有更高的光催化活性。利用活性物种捕获实验探讨其光催化降解过程的反应机理,实验结果显示O₂^-·和·OH是光催化降解过程的主要活性物种。     

Realizing high hydrogen evolution activity under visible light using narrow band gap organic photocatalysts

The design and synthesis of conjugated semiconducting polymers for photocatalytic hydrogen evolution have engendered intense recent interest. However, most reported organic polymer photocatalysts show a relatively broad band gap with weak light absorption ability in the visible light region, which commonly leads to a low photocatalytic activity under visible light. Herein, we synthesize three novel dithieno[3,2-b:2′,3′-d]thiophene-S,S-dioxide (DTDO) containing conjugated polymer photocatalysts by a facile C–H arylation coupling polymerization reaction. The resulting polymers show a broad visible light absorption range up to 700 nm and a narrow band gap down to 1.81 eV due to the introduction of the DTDO unit. Benefiting from the donor–acceptor polymer structure and the high content of the DTDO unit, the three-dimensional polymer PyDTDO-3 without the addition of a Pt co-catalyst shows an attractive photocatalytic hydrogen evolution rate of 16.32 mmol h⁻¹ g⁻¹ under visible light irradiation, which is much higher than that of most reported organic polymer photocatalysts under visible light.

Narrow band gap conjugated polymer photocatalysts containing dithieno[3,2-b:2′,3′-d]thiophene-S,S-dioxide show an attractive photocatalytic hydrogen evolution rate of 16.32 mmol h⁻¹ g⁻¹ under visible light irradiation.     

Ag负载CdMoO4光催化剂的制备及其催化性能

采用硼氢化钠还原法制备了Ag负载Cd Mo O4光催化剂。运用X射线粉末衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)等测试手段对催化剂的组成和结构进行了表征;采用紫外-可见漫反射光谱(UV-Vis DRS)和X射线光电子能谱(XPS)等技术对催化剂的光响应和表面状态进行了分析,考察了不同Ag负载量对Cd Mo O4紫外光降解罗丹明B和可见光选择性氧化苯甲醇性能的影响。结果表明,与Cd Mo O4相比,Ag/Cd Mo O4具有更高的光催化活性。利用活性物种捕获实验探讨其光催化降解过程的反应机理,实验结果显示O2-·和·OH是光催化降解过程的主要活性物种。     

Poly(N-isopropylacrylamide) thermoresponsive cross-linked conjugates containing polymeric soybean oil and/or polypropylene glycol

Synthesis, characterization and solution properties of a new series of the PNIPAM-soybean oil and/or polypropylene glycol, PPG, conjugates (conjugates also referred to as co-networks) have been described. For this purpose free radical polymerization of NIPAM monomer was initiated by macroinitiators based on PSB and/or PPG in order to obtain PSB-g-PNIPAM, PPG-g-PNIPAM and PSB-g-PPG-g-PNIPAM cross-linked graft copolymers. The autooxidation of soybean oil under air at room temperature rendered waxy soluble polymeric soybean oil peroxide associated with cross-linked parts. The soluble polymeric oil macro-peroxide isolated from the cross-linked part was used to initiate the free radical polymerization of NIPAM to give PSB-g-PNIPAM cross-linked copolymer. To obtain PPG-macromonomeric initiator, PPG-MIM, PPG-bis amino propyl ether with Mn 400 (or 2000) Dalton was reacted with 4,4′-azo bis cyanopentanoyl chloride and methacryloyl chloride, respectively. PPG-MIM also initiated the free radical polymerization of NIPAM at 80 °C to yield PPG-g-PNIPAM cross-linked thermoresponsive product. In order to obtain PSB-g-PPG-g-PNIPAM cross-linked triblock copolymer, NIPAM was polymerized by using the mixture of two macroinitiators, PSB and PPG-MIM. PSB contents in the graft copolymers were calculated via elemental analysis of nitrogen in graft copolymers. Thermal analysis, SEM, FTIR and ¹H NMR techniques were used in the characterization of the products. The effect of polymeric soybean oil, PSB, and/or PPG on the thermal response rate of poly(N-isopropylacrylamide, PNIPAM, cross-linked-graft copolymers swollen in water has been investigated by means of swelling-deswelling and drug release behaviors against to temperature change. Lower critical solution temperatures (LCST) of the cross-linked PNIPAM conjugates (conjugates also referred to as co-networks) were determined from the curves of swelling degrees versus solution temperatures. The response temperature of the hydrophobically modified PNIPAM conjugates was reduced to 27 °C, 23 °C and 27 °C for PSB-g-PNIPAM, PPG-g-PNIPAM and PSB-g-PPG-g-PNIPAM, respectively. We have found that the graft copolymers were not pH-responsive. In addition, higher pH ranges cause the hydrolysis of the PSB ester linkages, quickly and makes the cross-linked graft copolymers soluble.The fastest shrinking of the gels was observed by loosing water between 65% and 98% at 50 °C.Methyl orange (MO), was used as a model drug, loaded into cross-linked graft copolymers to examine and compare the effects of controlled release at lower and higher temperatures of lower critical solution temperature (LCST).     

Photocatalytic Degradation of Palm Oil Mill Effluent (POME) Waste Using BiVO4 Based Catalysts

Disposal of palm oil mill effluent (POME), which is highly polluting from the palm oil industry, needs to be handled properly to minimize the harmful impact on the surrounding environment. Photocatalytic technology is one of the advanced technologies that can be developed due to its low operating costs, as well as being sustainable, renewable, and environmentally friendly. This paper reports on the photocatalytic degradation of palm oil mill effluent (POME) using a BiVO₄ photocatalyst under UV-visible light irradiation. BiVO₄ photocatalysts were synthesized via sol-gel method and their physical and chemical properties were characterized using several characterization tools including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), surface area analysis using the BET method, Raman spectroscopy, electron paramagnetic resonance (EPR), and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). The effect of calcination temperature on the properties and photocatalytic performance for POME degradation using BiVO₄ photocatalyst was also studied. XRD characterization data show a phase transformation of BiVO₄ from tetragonal to monoclinic phase at a temperature of 450 °C (BV-450). The defect site comprising of vanadium vacancy (V_v) was generated through calcination under air and maxima at the BV-450 sample and proposed as the origin of the highest reaction rate constant (k) of photocatalytic POME removal among various calcination temperature treatments with a k value of 1.04 × 10⁻³ min⁻¹. These findings provide design guidelines to develop efficient BiVO₄-based photocatalyst through defect engineering for potential scalable photocatalytic organic pollutant degradation.     

Self-assembled metallasupramolecular cages towards light harvesting systems for oxidative cyclization

Designing artificial light harvesting systems with the ability to utilize the output energy for fruitful application in aqueous medium is an intriguing topic for the development of clean and sustainable energy. We report here facile synthesis of three prismatic molecular cages as imminent supramolecular optoelectronic materials via two-component coordination-driven self-assembly of a new tetra-imidazole donor (L) in combination with 180°/120° di-platinum(ii) acceptors. Self-assembly of 180° trans-Pt(ii) acceptors A1 and A2 with L leads to the formation of cages Pt₄L₂(1a) and Pt₈L₂(2a) respectively, while 120°-Pt(ii) acceptor A3 with L gives the Pt₈L₂(3a) metallacage. PF₆⁻ analogues (1b, 2b and 3b) of the metallacages possess a high molar extinction coefficient and large Stokes shift. 1b–3b are weakly emissive in dilute solution but showed aggregation induced emission (AIE) in a water/MeCN mixture as well as in the solid state. AIE active 2b and 3b in aqueous (90% water/MeCN mixture) medium act as donors for fabricating artificial light harvesting systems via Förster resonance energy transfer (FRET) with organic dye rhodamine-B (RhB) with high energy efficiency and good antenna effect. The metallacages 2b and 3b represent an interesting platform to fabricate new generation supramolecular aqueous light harvesting systems with high antenna effect. Finally, the harvested energy of the LHSs (2b + RhB) and (3b + RhB) was utilized successfully for efficient visible light induced photo-oxidative cross coupling cyclization of N,N-dimethylaniline (4) with a series of N-alkyl/aryl maleimides (5) in aqueous acetonitrile with dramatic enhancement in yields compared to the reactions with RhB or cages alone.

Synthesis of Pt(ii) based metallacages as aggregation induced emissive supramolecular architectures for fabricating artificial light harvesting systems for cross coupling cyclization under visible light is achieved.     

Boosting the photocatalytic nitrogen reduction to ammonia through adsorption-plasmonic synergistic effects

Ammonia is one of the most essential chemicals in the modern society but its production still heavily relies on energy-consuming Haber-Bosch processes. The photocatalytic reduction of nitrogen with water for ammonia production has attracted much attention recently due to its synthesis under mild conditions at room temperature and atmospheric pressure using sunlight. Herein, we report a high-performance Au/MIL-100(Cr) photocatalyst, comprising MIL-100(Cr) and Au nanoparticles in photocatalytic nitrogen reduction to ammonia at ambient conditions under visible light irradiation. The optimized photocatalyst (i.e., 0.10Au/MIL-100(Cr)) achieved the excellent ammonia production rate with 39.9 µg g_cat^?1 h^?1 compared with pure MIL-100(Cr) (2.73 µg g_cat^?1 h^?1), which was nearly 15 times that on pure MIL-100(Cr). The remarkable activity could be attributed to the adsorption-plasmonic synergistic effects in which the MIL-100(Cr) and Au are responsible to the strong trapping and adsorption of N₂ molecules and photo-induced plasmonic hot electrons activating and decomposing the N₂ molecules, respectively. This study might provide a new strategy for designing an efficient plasmonic photocatalyst to improve the photocatalytic performance of N₂ fixation under visible light irradiation.     

Ag@AgCl修饰的锐钛矿相TiO2纳米管的制备及其光催化性能

首先采用水热合成法和双氧水处理制备了具有锐钛矿相的TiO2纳米管,然后通过沉淀和光化学反应将Ag@AgCl纳米粒子负载于其上,从而制得TiO2纳米管负载的表面等离子体光催化剂.结果表明,经Ag@AgCl纳米粒子修饰后,锐钛矿相TiO2纳米管因表面等离子共振效应而对可见光具有明显的响应,光生电子-空穴对更容易分离,因而T...     

可见光照射下SiW12O404-/Resin光催化剂活化可见光照射下SiW12O404-/Resin光催化剂活化H2O2降解染料的研究

将杂多酸(SiW₁₂O₄₀^4-)负载到阴离子交换树脂上, 得到SiW₁₂O₄₀^4-/Resin (SWR)固相光催化剂, 在可见光的照射下, 可以有效地活化H₂O₂降解染料. 以罗丹明B (Rhodamine B, RhB)为模型化合物, 研究了不同条件下RhB的降解动力学, 以及降解过程中其UV-vis光谱及体系的总有机碳(Total Organic Carbon, TOC)变化情况, 结果表明RhB的共轭芳环结构被破坏, 矿化率为24.2%. 其它染料如孔雀绿(Malachite Green, MG)和吖啶橙(Acridine Orange, AO)等也可以被降解和矿化. 催化剂的循环实验表明SWR固相光催化剂易于分离, 并且具有良好的稳定性, 可以重复利用.     

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.     

A Novel Visible Light-Driven p-Type BiFeO3/n-Type SnS2 Heterojunction Photocatalyst for Efficient Charge Separation and Enhanced Photocatalytic Activity

This present investigation focused on novel p-type bismuth ferrite (BiFeO₃)/n-type tin sulfide (SnS₂) heterostructure photocatalyst has been favorably attained via a facile two-step process followed by co-precipitation approach for enhances the photocatalytic activity through the degradation of Methylene Blue (MB) and Rhodamine B (RhB) organic dyes under visible-light illumination. Structural, optical, and photocatalytic behavior of the prepared BiFeO₃ and BiFeO₃/SnS₂ photocatalysts are carefully explored. The photocatalytic efficiency of BiFeO₃/SnS₂ nanocatalyst was calculated to be 83%, 78% for MB and RhB, respectively, within 120 min illumination whereas the pure BiFeO₃ nanoparticle was 58% and 56% for MB and RhB. This prominent enhancement of visible light photocatalytic activity can be ascribed to the separation as well as the transfer of photogenerated charge carriers, successful exploitation of visible light absorption and donates the enlarged number of photocatalytic active sites by the formation of BiFeO₃/SnS₂ p-n heterojunction.

     

Photoelectrochemical Properties of Annealed Anodic TiO2 Layers Covered with CuOx

In this work, we present a systematic study on the influence of Cu²⁺ ion concentration in the impregnation solution on the morphology, structure, optical, semiconducting, and photoelectrochemical properties of anodic CuO_x-TiO₂ materials. Studied materials were prepared by immersion in solutions with different concentrations of (CH₃COO)₂Cu and subjected to air-annealing at 400 °C, 500 °C, or 600 °C for 2 h. The complex characterization of all studied samples was performed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), reflectance measurements, Mott–Schottky analyses, and photocurrent measurements. It was found that band gap engineering based on coupling CuO with TiO₂ (E_g~3.3 eV) is an effective strategy to increase the absorption in visible light due to band gap narrowing (CuO_x-TiO₂ materials had E_g~2.4 eV). Although the photoactivity of CuO-TiO₂ materials decreased in the UV range due to the deposition of CuO on the TiO₂ surface, in the Vis range increased up to 600 nm at the same time.     

Amino-Functionalized Titanium Based Metal-Organic Framework for Photocatalytic Hydrogen Production

Photocatalytic hydrogen production using stable metal-organic frameworks (MOFs), especially the titanium-based MOFs (Ti-MOFs) as photocatalysts is one of the most promising solutions to solve the energy crisis. However, due to the high reactivity and harsh synthetic conditions, only a limited number of Ti-MOFs have been reported so far. Herein, we synthesized a new amino-functionalized Ti-MOFs, named NH₂-ZSTU-2 (ZSTU stands for Zhejiang Sci-Tech University), for photocatalytic hydrogen production under visible light irradiation. The NH₂-ZSTU-2 was synthesized by a facile solvothermal method, composed of 2,4,6-tri(4-carboxyphenylphenyl)-aniline (NH₂-BTB) triangular linker and infinite Ti-oxo chains. The structure and photoelectrochemical properties of NH₂-ZSTU-2 were fully studied by powder X-ray diffraction, scanning electron microscope, nitro sorption isotherms, solid-state diffuse reflectance absorption spectra, and Mott–Schottky measurements, etc., which conclude that NH₂-ZSTU-2 was favorable for photocatalytic hydrogen production. Benefitting from those structural features, NH₂-ZSTU-2 showed steady hydrogen production rate under visible light irradiation with average photocatalytic H₂ yields of 431.45 μmol·g⁻¹·h⁻¹ with triethanolamine and Pt as sacrificial agent and cocatalyst, respectively, which is almost 2.5 times higher than that of its counterpart ZSTU-2. The stability and proposed photocatalysis mechanism were also discussed. This work paves the way to design Ti-MOFs for photocatalysis.     

Enhanced photocatalytic hydrogen production under visible light of an organic-inorganic hybrid material based on enzo[1,2-b:4,5-b']dithiophene polymer and TiO2

Titanium dioxide (TiO₂) has been limited in photocatalysis due to its wide band gap (3.2 eV) and limited absorption in the ultraviolet range. Therefore, organic components have been introduced to hybrid with TiO₂ for enhanced photocatalytic efficiency under visible light. Here, we report that benzo[1,2-b:4,5-b']dithiophene polymer was an ideal organic material for the preparation of a hybrid material with TiO₂. The energy band gap of the resulting hybrid material decreased to 2.9 eV and the photocatalytic hydrogen production performance reached 745.0 µmol g^?1 h^?1 under visible light irradiation. Meanwhile, the material still maintained the stability of hydrogen production performance after 40 h of photocatalytic cycles. The analysis of the transient current response and electrochemical impedance revealed that the main reasons for the enhanced water splitting of the hybrid materials were the faster separation of electron hole pairs and the lower recombination of photocarrier ions. Our findings suggest that polythiophene is a promising organic material for exploring hybrid materials with enhanced photocatalytic hydrogen production.     

Synthesis of BiVO4-GO-PVDF nanocomposite: An excellent,newly designed material for high photocatalytic activity towards organic dye degradation by tuning band gap energies

BiVO_4-GO-PVDF (PVDF = Polyvinylidene Difluoride) photocatalyst is successfully synthesized by ultrasonication method and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques. Morphology of BiVO₄-GO-PVDF looks like a human embryo embedded inside an amniotic sac. Photocatalytic performance of BiVO₄-GO-PVDF for decolorization of methylene blue is investigated. BiVO₄-GO-PVDF system reveals enhanced photocatalytic activity degradation of methylene blue (MB), Rhodamine B (RhB) & Safranin-O (SO) in water under visible light irradiation as compared to the pure BiVO₄ catalyst, BiVO₄ & PTFE decorated on the graphene sheet. The experimental result reveals that the covering of graphene sheets in this composite catalyst enhances photocatalytic performance under visible light. This enhanced activity is mainly attributed to effective quenching of the photogenerated electron-hole pairs confirmed by photoluminescence spectra. Trapping experiments of radicals and holes were conducted to detect reactive species generated in the photocatalytic system, experimental results revealed that direct hole oxidation reaction is obviously dominant during photocatalytic reactions on the BiVO₄-GO-PVDF system.     

Fabrication of polymeric micelles with core–shell–corona structure for applications in controlled drug release

Thermo-responsive polymeric micelles of poly (ethylene glycol)-b-poly(2-hydroxyethyl methacrylate-g-lactide)-b-poly(N-isopropylacrylamide) (PEG-P(HEMA-PLA)-PNIPAM) with core–shell–corona structure were fabricated for applications in controlled drug release. The graft copolymer of PEG-P(HEMA-PLA)-PNIPAM was self-assembled into core–shell micelles with a densely PLA core and mixed PEG/PNIPAM shells at 25 °C in aqueous media. By increasing the temperature above the lower critical solution temperature of PNIPAM, these core–shell micelles could be converted into core–shell–corona micelles because of the collapse of PNIPAM block on the PLA core as the inner shell and the soluble PEG block stretching outside as the outer corona. Anticancer drug doxorubicin (DOX) was loaded in the polymeric micelles as a model drug. Compared with polymeric micelles formed by liner PEG-b-PLA-b-PNIPAM triblock copolymer, these polymeric micelles exhibited higher loading capacity, and release of DOX from the polymeric micelles with core–shell–corona structure was well-controlled.     

InOOH纳米晶的控制合成及其液相光催化性能

以硝酸铟作为前驱体,在蒸馏水和乙二胺的混合溶剂中制备出了InOOH纳米晶,详细地考察了反应溶剂及温度对终产物的影响。利用X射线粉末衍射(XRD)、紫外-可见漫反射光谱(UV-Vis DRS)、扫描电子显微镜(SEM)和透射电镜(TEM)对样品的晶相结构、光吸收性质及其形貌进行了详细的表征。考察了样品在紫外光下及可见光下对液相中的染料罗丹明B(RhB)的光催化降解性能。发现InOOH在紫外光下可以彻底分解RhB,而在可见光下只能使RhB脱色。InOOH在紫外光和可见光下对RhB的分解遵循两种不同的反应机制。     

Synthesis,characterization and the rapid response property of the temperature responsive PVP-g-PNIPAM hydrogel

In this study, a poly(N-vinylpyrrolidone)-graft-poly(N-isopropylacrylamide) hydrogel (PVP-g-PNIPAM) was synthesized through the “grafting from” process. Grafting of temperature responsive poly(N-isopropylacrylamide) (PNIPAM) brushes was carried out from the poly(N-vinylpyrrolidone) (PVP) synthesized with free radical polymerization and functionalized with ATRP initiator, PVP–Br, which was performed through a bromination reaction between pendant allylic groups of the PVP and N-bromosuccinimide (NBS). The structure of the initiator and PVP-g-PNIPAM was characterized by ultraviolet and visible (UV/Vis) absorption, nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared (FTIR) measurements. Scanning electron microscope (SEM) morphology measurement displayed some dendritic grafted chains dangling onto the pore wall of the hydrogel.The characteristic in response to the change in environmental temperature was investigated by the fluorescence anisotropy and UV/Vis transmittance measurements. The results showed that the PVP-g-PNIPAM hydrogel exhibited rapid response to the change in environmental temperature due to free and mobile graft chains compared with the P(VP-co-NIPAM) hydrogel, which was prepared by free radical copolymerization in this work.     

ZnO修饰提升花状BiOBr的可见光催化降解罗丹明B性能

以Bi(NO₃)₃·5H₂O、Zn(CH₃COO)₂·2H₂O和NaBr为前驱体,采用简单溶剂热法制备BiOBr/ZnO三维花状微纳米复合材料。采用X射线衍射、扫描电子显微镜、X射线光子能谱、N₂吸附-脱附、光致发光和电子顺磁共振等分析技术对其理化性质进行了表征。通过可见光催化降解罗丹明B(RhB)的实验测试了复合材料的光催化性能。结果表明ZnO含量为5%的BiOBr/ZnO光催化活性最优,RhB降解率在50 min后达到98.3%,其降解速率常数是纯ZnO和BiOBr的6.3倍和3.4倍,并且具有较高的稳定性。复合材料光催化性能增强的可能原因为ZnO的引入增强了可见光的吸收和光生载流子的电荷分离效率。