铈硅包覆金红石型钛白粉及光催化性研究

采用溶胶-凝胶法,制备了铈硅包覆金红石型钛白粉,通过正交实验考察了浆液浓度、分散剂用量和两种包膜剂含量对铈硅包覆金红石型钛白粉性能的影响。采用Nano-ZS型粒度仪、扫描电镜（SEM）、透射电镜（TEM）和能谱（EDS）等测试手段,对金红石型钛白粉的Zeta电位、表面形貌和元素进行了表征。结果表明：在水浴温度为80 ℃左右、转速为600 r/min、浆液质量浓度为400 g/L、分散剂质量分数为0.1%、二氧化铈质量分数为3%、二氧化硅质量分数为4%的条件下,金红石型钛白粉表面包覆了两层均匀而致密的二氧化硅和二氧化铈膜;罗丹明B光催化降解实验证实,铈硅包覆明显改善了金红石型钛白粉的光催化屏蔽性。     

MOFs诱导中空Co3O4/CdIn2S4合成及光催化CO2还原性能研究

光催化二氧化碳转化技术,不仅可以利用取之不尽用之不竭的太阳光能,而且可将二氧化碳转化为高附加值的碳基燃料,受到研究者们的广泛关注。实验设计合成了新颖的中空结构的Co₃O₄/CdIn₂S₄异质结光催化剂。两种半导体的高效耦合作用极大地促进了光生载流子分离,同时形成更多暴露活性位点。基于异质结独特的结构优势,表现出高效的CO₂还原性能,5% Co₃O₄/CdIn₂S₄ 的CO生成速率达74 μmol·g^-1·h^-1,与单体CdIn₂S₄相比,不仅活性得到很大提升,同时CO选择性达到100%。     

A unique Cu2O/TiO2 nanocomposite with enhanced photocatalytic performance under visible light irradiation

A unique Cu₂O/TiO₂ nanocomposite with high photocatalytic activity was synthesized via a two-step chemical solution method and used for the photocatalytic degradation of organic dye. The structure, morphology, composition, optical and photocatalytic properties of the as-prepared samples were investigated in detail. The results suggested that the Cu₂O/TiO₂ nanocomposite is composed of hierarchical TiO₂ hollow microstructure coated by a great many Cu₂O nanoparticles. The photocatalytic performance of Cu₂O/TiO₂ nanocomposite was evaluated by the photodegradation of methylene blue (MB) under visible light, and compared with those of the pure TiO₂ and Cu₂O photocatalysts synthesized by the identical synthetic route. Within 120 min of reaction time, nearly 100% decolorization efficiency of MB was achieved by Cu₂O/TiO₂ photocatalyst, which is much higher than that of pure TiO₂ (26%) or Cu₂O (32%). The outstanding photocatalytic efficiency was mainly ascribed to the unique architecture, the extended photoresponse range and efficient separation of the electron-hole pairs in the Cu₂O/TiO₂ heterojunction. In addition, the Cu₂O/TiO₂ nanocomposite also retains good cycling stability in the photodegradation of MB.     

Plasmonic Au nanoparticles supported on both sides of TiO2 hollow spheres for maximising photocatalytic activity under visible light

A strategy of intensifying the visible light harvesting ability of anatase TiO₂ hollow spheres (HSs) was developed, in which both sides of TiO₂ HSs were utilised for stabilising Au nanoparticles (NPs) through the sacrificial templating method and convex surface-induced confinement. The composite structure of single Au NP yolk-TiO₂ shell-Au NPs, denoted as Au@Au(TiO₂, was rendered and confirmed by the transmission electron microscopy analysis. Au@Au(TiO₂ showed enhanced photocatalytic activity in the degradation of methylene blue and phenol in aqueous phase under visible light surpassing that of other reference materials such as Au(TiO₂ by 77% and Au@P25 by 52%, respectively, in phenol degradation.     

Generation of hydrogen under visible light irradiation with enhanced photocatalytic activity of Bi2WO6/Cu1.8Se for organic pollutants under Vis‐NIR light reign

To make better use of solar light, a new Bi₂WO₆/Cu_1.8Se photocatalyst active to visible and near‐infrared light has been synthesized by a facile hydrothermal method. The composites were characterized by X‐ray diffractometry (XRD), scanning electron microscopy (SEM), UV‐vis diffuse reflectance spectroscopy (DRS), and photoluminescene (PL). The photocatalytic activities of Bi₂WO₆/Cu_1.8Se are evaluated by degrading Congo red solution and hydrogen generation from water. It was found that the molar percentage of Cu_1.8Se had great effects on the morphology and photocatalytic property of the Bi₂WO₆/Cu_1.8Se heterojunctions, and the composite with suitable molar amount of Cu_1.8Se exhibits much enhanced photocatalytic activity for Congo red degradation under visible and near‐infrared light irradiation and for hydrogen generation under visible light compared to Bi₂WO₆. The significant improvement photocatalytic activity of the composite could be attributed to its good light absorption, suitable band gap structure, and effective separation of photogenerated electron‐hole pairs of Bi₂WO₆/Cu_1.8Se heterojunction. This work presents an efficient multifunction photocatalyst owning the activity both for water splitting under visible light and for organic contaminants decomposition under visible‐near‐infrared light.     

Interface engineering for enhancing electrocatalytic oxygen evolution reaction of CoS/CeO2 heterostructures

To realize renewable energy conversion,it is important to develop low-cost and high-efficiency electrocatalyst for oxygen evolution reaction.In this communication,a novel bijunction CoS/CeO₂ electrocatalyst grown on carbon cloth is prepared by the interface engineering.The interface engineering of CoS and CeO₂ facilitates a rapid charge transfer from CeO₂ to CoS.Such an electrocatalyst exhibits outstanding electrocatalytic activity with a low overpotential of 311 mV at 10 mA·cm?2 and low Tafel slope of 76.2 mV·dec?1,and is superior to that of CoS(372 mV)and CeO₂(530 mV)counterparts.And it has long-term durability under alkaline media.     

Novel NiTiO3/Ag3VO4 composite with enhanced photocatalytic performance under visible light

A novel NiTiO₃/Ag₃VO₄ composite with type-II band alignment was prepared using a modified Pechini/precipitation method. The FESEM image of the NiTiO₃/Ag₃VO₄ heterostructure reveals the dispersion of small NiTiO₃ particles on the Ag₃VO₄ surfaces, indicating the close interfacial connection between NiTiO₃ and Ag₃VO₄. The heterojunction shows remarkably higher photocatalytic activity than pure NiTiO₃ and Ag₃VO₄ due to an increase in light harvesting efficiency and an efficient electron–hole separation being induced by the suitably matching conduction and valence band levels. Based on the VB-XPS and UV–vis DRS results, a possible electron–hole transfer mechanism at the NiTiO₃/Ag₃VO₄ interface is proposed.     

Alkali-free synthesis of a novel heterostructured CeO2-TiO2 nanocomposite with high performance to reduce Cr(VI) under visible light

In this study, a novel CeO₂-TiO₂ nanocomposite denoted as CeO₂-3TiO₂ was successfully synthesized via a facile one pot hydro-thermal method without alkali. It exhibits high photocatalytic reduction reactivity toward Cr(VI) under visible light. The photocatalytic reactivity of CeO₂-3TiO₂ is 18 times higher than that of pure CeO₂, 28 times higher than pure TiO₂, 15 times higher than the sample of simply mixed CeO₂ and TiO₂. The solution with Cr(VI) initial concentration of 2780 ppb can be fast photoreduced by CeO₂-3TiO₂ in 60 min under visible light to meet the criterion of U.S. Environmental protection Agency. Characterization results indicate CeO₂-3TiO₂ has the good crystal form of heterojunction structure, narrow pore size distribution, narrow energy gap and high photogenerated electron-hole separation efficiency. Based on the experimental results, a speculated photocatalytic mechanism was proposed.     

CuGaO2/TiO2 heterostructure nanosheets: Synthesis,enhanced photocatalytic performance,and underlying mechanism

Effective separation and fast transport of photogenerated carriers are vital links determining the photocatalytic performance. Heterostructure constructed by two complementary semiconductors is a feasible strategy to achieve this goal. By one-pot hydrothermal method, 0D-TiO₂ nanoparticles are loaded onto 2D-CuGaO₂ nanosheets, forming a mixed dimension, closely combined heterostructure. The photocurrent density of CuGaO₂/TiO₂ heterostructure is ∼16.6 μA/cm², which is 1.24 times higher than that of pristine CuGaO₂ nanosheets (∼13.4 μA/cm²) and 15 times higher than that of TiO₂ (∼1.1 μA/cm²). In the tetracycline hydrochloride degradation experiment, the degradation efficiency of tetracycline hydrochloride by CuGaO₂/TiO₂ heterostructure reached 99% within 90 min, which was 1.2 times the degradation efficiency of CuGaO₂ nanoparticles (82%) and 20.2 times the degradation rate of TiO₂ (4.9%). A series of experimental characterizations combined with density functional theory calculations revealed that it is the built-in electric field in the CuGaO₂/TiO₂ interface region that drives the photogenerated electron–hole pairs to travel in the opposite direction, thus inhibiting their recombination. Furthermore, the energy band offset of the CuGaO₂/TiO₂ interface makes it easier for the photogenerated holes and electrons to gather onto the valence band of the CuGaO₂ nanosheets and the conduction band of the TiO₂ nanoparticles, respectively. Therefore, appropriate interface lattice matching, suitable configuration of band gap and band edge positions, and strong opposite drive of interface electric field enable CuGaO₂/TiO₂ heterostructure to achieve wide spectral response and effective separation of photogenerated electron–hole pairs at the same time.     

Solution combustion synthesis of novel PrFeO3/CeO2 nanocomposite with enhanced photo-Fenton activity under visible light

In this study, we successfully synthesized PrFeO₃/CeO₂-based nanocomposites with different mass contents of СeO₂ (0–18 wt%) via solution combustion with subsequent heat treatment in air. The results of EDXS and PXRD confirmed the presence of two phases in nanocomposites: a PrFeO₃ orthorhombic phase with an average crystallite size of 13.6–36.6 nm and a СeO₂ cubic phase in the form of an ultradisperse phase with an average particle size of 7.4–11.5 nm depending on the mass content of СeO₂. We characterized the morphology, porosity, and specific surface structure of the powders by scanning electron microscopy, transmission electron microscopy, and adsorption–structural analysis, which established the foam-like morphology of nanopowders with a predominantly mesoporous structure. The specific surface area varied in the range of 8.8–19.4 m²/g for different СeO₂ contents. We studied the optoelectronic properties of the nanocomposites with UV–visible diffuse reflection spectroscopy, which determined the values of the band gap of the PrFeO₃ phase actively absorbing radiation in the visible region (2.07–2.13 eV). Based on the adsorption–photocatalytic properties of the obtained nanocomposites, we established the presence of a synergistic effect from the addition of CeO₂ to PrFeO₃. We studied the adsorption capacity of the samples during the adsorption of methyl violet, and we analyzed the resulting adsorption isotherm in accordance with the Freundlich model. The obtained results indicated increased dye adsorption in the presence of CeO₂, with the maximum value of K_f = 45.7 observed at 15 wt%. We studied the photocatalytic Fenton-like activity of nanopowders during the degradation of methyl violet under the influence of visible light. We established he presence of a positive effect of CeO₂ additive. At 9 wt% content, the maximum photocatalytic reaction rate constant was reached at 0.056 min⁻¹, which was previously unavailable for analogical Fenton-like photocatalysts based on REE orthoferrites. Based on the conducted studies, we propose a possible mechanism of the photo-Fenton-like decomposition of organic pollutants in the presence of PrFeO₃/CeO₂ under the influence of visible light. The obtained nanocomposite materials were also characterized by high cyclic stability and the potential for magnetically controlled separation from the reaction solution, showing their potential as a basis for photocatalysts in wastewater treatment from dyes and other organic pollutants.     

CeO2-ZnO/KIT-6催化剂在光催化吸附脱硫中的应用

光催化吸附脱硫技术在油品脱硫领域引起了极大的关注,具有高光催化活性和有机硫化物吸附能力的双功能材料的开发是关键。首次合成了3D介孔二氧化铈-氧化锌/KIT-6（CeO₂-ZnO/KIT-6）催化剂,并应用于二苯并噻吩（DBT）的光催化吸附脱硫。通过X射线衍射（XRD）、氮气吸附-脱附和透射电子显微镜（TEM）等手段对催化剂进行表征,并研究了催化剂在光照下对DBT的转化性能。实验结果表明,在没有额外添加氧化剂（例如氧气、过氧化氢或有机氧化剂）的情况下,CeO₂-ZnO/KIT-6具有很好的光催化脱硫能力,当二氧化铈质量分数为10%、氧化锌质量分数为15%时,催化剂CeO₂-ZnO/KIT-6对DBT的转化率可达90%,最大吸附量（以硫计）为8.1 mg/g。无氧化剂体系对于燃料的后续处理非常有利,并且可以明显降低脱硫成本。     

CoPcS/Bi_2WO_6复合材料的制备及其光催化性能

采用超声复合方法制备了磺化酞菁钴/钨酸铋纳米复合材料,以四环素为降解对象,考察了CoPcS/Bi2WO6复合材料的光催化性能。结果表明,当磺化酞菁钴的掺杂质量为1%时,CoPcS/Bi2WO6对四环素具有较好的光催化活性,反应60 min后,降解率可达80%左右。     

BiOCl/g-C3N4异质结催化剂可见光催化还原CO2

以KCl、Bi（NO₃）₃和类石墨氮化碳（g-C₃N₄）为前体,采用水热法成功制备了BiOCl/g-C₃N₄异质结光催化剂,并进行可见光催化还原CO₂,考察了催化剂的活性及稳定性,同时研究BiOCl：g-C₃N₄（摩尔比）、催化剂用量和光照强度对光催化还原CO₂的影响。结果表明,在水蒸气的存在下,BiOCl/g-C₃N₄较纯BiOCl和g-C₃N₄具有更高的光催化还原CO₂活性,在催化剂用量为0.1 g,光照强度为2.413×10^-6 einstein·min^-1·cm^-2,BiOCl：g-C₃N₄摩尔比为1：1的异质结催化剂显示了最高的光催化还原CO₂活性,且可见光催化剂在5次套用实验后其活性基本不变。基于X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、X射线光电子能谱（XPS）、比表面积测试（BET）和紫外-可见（UV-vis）吸收光谱表征,可以推断BiOCl和g-C₃N₄之间形成的p-n结能有效分离光生电子和空穴,是增强光催化剂活性的主要原因。     

可见光下Cu2O/TiO2催化臭氧氧化头孢曲松钠性能研究

抗生素是治疗各种传染病的常用药物,但残留在水环境中的抗生素会对生态系统造成威胁。因此,探索去除水环境中抗生素的有效方法具有重要意义。由于光催化臭氧氧化技术可以高效降解和矿化水体中的污染物,该技术受到广泛关注。本工作通过浸渍-化学还原法制备Cu₂O/TiO₂复合材料并将其作为可见光催化臭氧氧化头孢曲松钠(CRO)的催化剂。利用X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、比表面积分析仪(BET)和紫外-可见漫反射光谱仪(UV-Vis DRS)对Cu₂O/TiO₂形貌结构和光学性能进行表征,考察了Cu₂O/TiO₂配比、Cu₂O/TiO₂投加量、臭氧浓度、头孢曲松钠初始浓度、溶液初始pH值等因素对可见光催化臭氧氧化头孢曲松钠的影响。结果表明,Cu₂O对TiO₂的掺杂改性使材料孔容和平均孔径增大,能带宽度减小,...     

钒酸铋的制备及可见光降解罗丹明B的研究

以偏钒酸铵和碳酸铋为原料,用NaOH调节体系pH,水热法合成钒酸铋（BiVO₄）光催化剂。利用XRD和UV-Vis漫反射对样品的晶型结构和光吸收特性进行表征分析。以罗丹明B为目标降解物,卤素灯（λ＞400 nm）为光源,探讨水热温度、水热时间对合成BiVO₄催化剂的可见光催化活性影响。结果表明,在水热温度为200 ℃、水热时间为8 h的条件下合成的钒酸铋光解效率最高。实验还研究了罗丹明B水溶液pH、催化剂投加量对光催化罗丹明B降解率的影响。结果表明,在罗丹明B水溶液pH为3、初始质量浓度为10 mg/L、每60 mL溶液催化剂投加量为0.4 g时能达到较好的光催化效果,反应2 h后降解率可达97%。     

Au nanoparticles-doped g-C3N4 nanocomposites for enhanced photocatalytic performance under visible light illumination

Surface and bandgap engineering of graphitic carbon nitride (g-C₃N₄) could be vital in enhancing photocatalytic performance by suppressing the recombination rate of photogenerated electron-hole pairs. The present report investigated the doping effects of various wt.% (0.2–5.0%) of gold nanoparticles (Au NPs) to g-C₃N₄ (Au/g-C₃N₄) for the enhancement of the photocatalytic efficiency of g-C₃N₄ nanocomposites. A straightforward and cost-effective synthesis methodology has been applied for the desired nanocomposites. Relevant characterization tools such as XRD, XPS, TEM, FTIR, and UV–Vis were utilized to analyze various physicochemical properties. The TEM images clearly show that spherical Au NPs were homogeneously distributed into the thin carbon nitride graphitic layers, confirming the successful doping of Au. The higher-magnification TEM image confirms that the sizes of the Au NPs varied from 15 to 25 nm. The photoactivity of the newly designed Au/g-C₃N₄ nanocomposites has been evaluated for the degradation of both methylene blue dye and the drug gemifloxacin mesylate, and their efficiencies were compared with that of bare g-C₃N₄. Our findings revealed that Au/g-C₃N₄ nanocomposites with various Au contents had superior photocatalytic activity compared to bare g-C₃N₄. However, the 1%Au/g-C₃N₄ nanocomposite could be considered the optimum photocatalyst, producing 95.13% destruction of the target dye molecule in 90 min, in contrast to the 69% achieved with bare g-C3N4, under the clean energy of visible light illumination. Additionally, the photodegradation rate of the 1%Au/g-C₃N₄ nanocomposite is 2.69 times higher than the rate of bare g-C₃N₄. This report might open a new gateway towards a straightforward and cost-effective synthesis approach for Au/g-C₃N₄ nanocomposites and provides a smooth and robust platform for the utilization of this new nanocomposite for environmental remediation processes.