微量Ag_3PO_4改性g-C_3N_4的可见光催化活性研究

采用一种简易方法制备了较低Ag3PO4含量的Ag3PO4/g-C3N4复合可见光催化剂,采用X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、紫外可见漫反射光谱(UV-vis DRS)、荧光光谱(PL)和X射线光电子能谱(XPS)等对Ag3PO4/gC3N4进行了系统分析与表征。通过在Ag3PO4/g-C3N4存在条件下甲基橙的光降解反应,考察该催化剂的可见光催化活性。结果表明,所制备的复合材料中确实存在Ag3PO4,Ag3PO4的引入对gC3N4晶型结构没有明显的影响,但显著提高了其在可见光区的吸收能力和光生电子/空穴对的分离效率,提高了其可见光催化活性。     

Depositing Ag3PO4 on WO3 hollow microspheres at room temperature for rapid photocatalytic degradation of Rhodamine B

A series of WO₃ hollow microspheres decorated with Ag₃PO₄ nanoparticles (APW) composites with Ag₃PO₄:WO₃ mass percentage of 20% (20APW), 30%(30APW), 40%(40APW) and 50% (APW) were successfully synthesized, characterized and tested for the degradation of the Rhodamine B(RhB) under 300 ?W xenon lamp radiation. The photocatalytic results showed that the photocatalytic degradation performances of WO₃ hollow microspheres decorated with Ag₃PO₄ nanoparticles on RhB were significantly enhanced, which were much higher than that of individual Ag₃PO₄ and WO₃. Especially for 40APW, RhB can be completely degraded within 10 ?min. The order of degradation efficiency is 20APW<50APW< 30APW<40APW. The rate constant of 40APW (0.3902 min^?1) is about 81.3 times that of WO₃ (0.0048 min^?1). The diffuse reflection, photoluminescence and electrochemical impedance tests showed that the formation of Ag₃PO₄/WO₃ composite structure broadened the light absorption range, reduced the recombination rate of photogenerated electrons and holes, and decreased the resistance to charge transfer, which are beneficial to the improvement of photocatalytic performance. The capture agent experiments were carried out with 40APW, which specified the primary role of h⁺ and ?O₂^? in the degradation of RhB. The formation of heterojunction between Ag₃PO₄ and WO₃ that effectively separates photogenerated electrons and holes are contributed to the enhancement of photocatalytic properties of APW composites.     

可见光催化剂Ag_3VO_4的制备、表征及其光催化性能的研究

通过化学沉淀的方法来制备光催化剂Ag3VO4,用紫外-可见光谱、X射线衍射和荧光光谱对其进行表征.通过光催化还原Cr6+和光催化氧化甲基橙的效率来评价该催化剂的活性.实验研究了不同的制备条件对Ag3VO4催化活性的影响.实验结果表明,在可见光下,在过量银条件下制备的Ag3VO4有较好的光催化氧化活性和光催化还原活性,且其紫外-可见吸收光谱有较大程度的红移,提高了对光的利用率.实验同时还研究了在过量银条件下制备出的Ag3VO4的稳定性和循环次数.同时对影响Ag3VO4的光催化活性的机理还进行了探讨.     

Ag/TiO_2/AC光催化氧化NO性能研究

以活性炭(AC)为载体,采用溶胶-凝胶法和浸渍法制备新型光催化剂Ag/TiO_2/AC,利用SEM、XRD、BET和UV-Vis光谱等手段对样品进行了表征,并以模拟烟气中的NO为对象,进行光催化氧化性能测试。结果表明,Ag/TiO_2/AC的比表面积为895.21 m~2/g,且对光响应波长已扩展到可见光区,该催化剂在光催化氧化NO反应中具有优异的活性,NO的氧化率高于60.5%。     

混合溶剂热法合成Ag／AgBr复合物及其光催化性质

以AgN03,KBr为原料,运用混合溶剂热法合成了Ag／AgBr光催化剂,利用X射线衍射（XRD）、透射电子显微镜（TEM）、扫描电镜（SEM）、电子衍射能谱（EDS）、紫外-可见（UV—Vis）光谱等技术对样品进行了表征。以甲基橙（MO）,甲基蓝（Mb）,罗丹明B（RhB）为目标降解物,考察了该光催化剂在可见光辐射下（λ〉420nm）的光催化性能。并且进行了不同的合成方法、尿素与十二烷基苯磺酸钠（SDBS）的不同用量、乙二醇与乙醇的不同体积比对Ag／AgBr样品光催化性能的影响。结果表明：混合溶剂热法合成样品的光催化活性要高于水热法合成的样品,尿素与SDBS的添加量分别为10mmol和0．2g,乙二醇与乙醇的体积比为3：1时,复合物Ag／AgBr表现出最佳的光催化性能。     

Synthesis of BiOCl photocatalyst by a low-cost,simple hydrolytic technique and its excellent photocatalytic activity

A novel photocatalyst, bismuth oxychloride (BiOCl) micro-nano particles with a fine ferrite plate structure, was prepared by a low-cost, simple hydrolytic method. The as-prepared BiOCl was characterized by scanning electron microscopy (SEM), thermogravimetric analysis-differential thermal analysis (TGA-DTA), X-ray diffraction (XRD), and UV-vis diffuse reflectance spectra (DRS). The effects of preparation conditions such as sodium dodecyl benzene sulfonate (SDBS) dispersant, HCl concentration, and heat treatment temperature on BiOCl performances were investigated. Moreover, its photocatalytic activity was evaluated on the degradation of methylene orange (MO) and was compared with that of TiO₂ (P25). The experimental results confirmed that BiOCl micro-nano particles prepared with SDBS, the HCl concentration of 1.5 mol/L, and the heat treatment temperature of 80℃ exhibited the best performance for the photodegradation of MO solution, and they showed good stability and better photocatalytic activity than P25 photocatalyst.     

Ag/TiO2光催化剂的表面性能表征

采用光催化还原法将 Ag沉积于 Ti O2 膜表面制备出负载型 Ag/Ti O2 光催化剂 ,通过 SEM、EDS检测出 Ti O2 表面上 A g元素的存在 ,由 TEM显示 Ag颗粒分散的均匀性 ,XPS图谱证实了 Ag是按光催化还原反应机理以单质形式存在 ,对低浓度甲基橙溶液光催化降解结果表明 ,沉积的单质 Ag对 Ti O2 光催化剂的降解活性有很大的提高作用。     

Magnetically separable and visible light-active Ag/NiCo_2O_4 nanorods prepared by a simple route for superior photodegradation of atrazine in water

Atrazine(ATZ) is a known herbicide used in agriculture and caused many concerns according to its toxicity.Herein,we have prepared NiCo_2 O_4 nanorods that can work as a photocatalyst under visible light exposure by Ag loading through a simple route.The characterizations revealed the role of Ag for improving the structural,optical and optoelectronic properties of the produced photocatalyst.The Ag loading with 5 wt% confirms the minimization of the bandgap from 3.6 down to 2.57 eV with enhanced visible light absorption and sustaining the magnetic properties.The Ag/NiCo_2 O_4 nanorods showed a superior photodegradation of ATZ within 20 min at2.0 g L~(-1) with excellent recyclability.The enhancement of the photocatalytic activity is referred to the local surface plasmon resonance of Ag-loaded photocatalyst.This reduces the electron-hole recombination and outperforms the unloaded sample.This work is highlighting the application of magnetically separable spinel photocatalysts for the removal of herbicides and water remediation.     

<Emphasis Type="Italic">Ab initio</Emphasis> study of the effects of Ag/Mn doping on the electronic structure of LiFePO<Subscript>4</Subscript>

Based on density functional theory （DFT） of the first-principle for the cathode materials of lithium ion battery, the electronic structures of Li（Fe1-x）PO4 （Me = Ag/Mn, x = 0-0.40） are calculated by plane wave pseudo-potential method using Cambridge serial total energy package （CASTEP） program. The calculated results show that the Fermi level of mixed atoms Fe1-xAgx moves into its conduction bands （CBs） due to the Ag doping. The Li（Fe1-xAgx）PO4 system displays the periodic direct semiconductor characteristic with the increase of Ag-doped concentration. However, for Fe1-xMnx mixed atoms, the Fermi level is pined at the bottom of conduction bands （CBs）, which is ascribed to the interaction between Mn（3d） electrons and Fe（4s） electrons. The intensity of the partial density of states （PDOS） near the bottom of CBs becomes stronger with the increase of Mn-doped concentration. The Fermi energy of the Li（Fe1-xMnx）PO4 reaches maximum at x = 0.25, which is consistent with the experimental value of x = 0.20. The whole conduction property of Mn-doped LiFePO4 is superior to that of Ag-doped LiFePO4 cathode material, but the structural stability is reverse.     

Preparation and photocatalytic properties of ilmenite NiTiO<Subscript>3</Subscript> powders for degradation of humic acid in water

The powders of ilmenite structure NiTiO₃ were prepared by a modified Pechini process using tetrabutyl titanate and nickel acetate as raw materials, and using citric acid and ethanol as a chelating agent and a solvent respectively. The powder samples were characterized by thermogravimetric and differential thermal analysis (TG-DTA) and X-ray diffraction (XRD). The photocatalytic activity of NiTiO₃ under the irradiation of ultraviolet rays (UV) light was evaluated by degrading humic acid (HA) in water as a probe reaction. The possible photodegradation mechanism was studied by the examination of active species ·OH, ·O₂⁻, and holes (h⁺) through adding scavengers. The TG-DTA and XRD results indicated that the good crystal structure of ilmenite phase NiTiO₃ could be obtained when the Ni-Ti citrate complex was calcined at 600°C. The photocatalytic activity experiments indicated that NiTiO₃ had favourable photocatalytic activity under the irradiation of UV light, and the photocatalytic degradation rate of HA reached 95.3% after a 2.5 h reaction with the photocatalyst calcined at 600°C and a photocatalyst dosage of 0.4 g/L. The possible photocatalytic mechanism was deduced that holes (h⁺) and ·OH radicals are the major reactive active species in the photocatalytic reaction, and dissolved oxygen plays a weak role in the degradation of HA.     

PVP-assisted laser ablation growth of Ag nanocubes anchored on reduced graphene oxide(rGO) for efficient photocatalytic CO_2 reduction

Metallic nanoparticles loaded graphene nanocomposites have been widely studied for various scientific and technological applications. In this study, a facile method was reported to realize a straightforward growth of shape and size-controllable of metallic nanoparticles, and the subsequent hybridization with graphene in solution by strategically coupling wet-chemical route and laser ablation. By mixing graphene oxide(GO) with a tunable concentration level of polyvinylpyrrolidone(PVP) in aqueous solution, Ag nanocubes with a face-centered cubic crystal structure were generated by pulsed laser ablation and then mounted on GO nanosheets with the assistance of PVP. The preferential adsorption of PVP to Ag(100) crystal face led to the production of Ag nanocubes with exposed(100) facet. The result showed that the morphological yield of spherical particles decreased with the increase in PVP concentration. X-ray diffraction(XRD) and UV–visible spectroscopy analyses confirmed that GO was partially reduced. In the reduction of CO_2 gas, the photocatalytic conversion rate could achieve 133.1 μmol g~(-1) h~(-1) in 6 hrs for cubic Ag-loaded reduced GO composites.     

羟基磷灰石负载磷酸银光催化降解染料的研究

采用溶液离子交换法成功制备了羟基磷灰石负载的Ag3PO4复合光催化剂 (Ag3PO4/HA). 对XRD、TEM 对制备出的催化剂进行表征,研究了有光和无光条件下对亚甲基蓝的降解性能,结果表明,Ag3PO4/HA降解性能良好,对银离子的利用效率较纯Ag3PO4高, Ag3PO4/HA的投加剂量,银负载量以及亚甲基蓝溶液的质量浓度对光催化降解效果有很大的影响.     

光还原法制备Ag/Bi2WO6可见光催化剂及其性能研究

利用离子液体辅助醇热法制备了具有较高活性的Bi_2WO_6可见光催化剂,并进一步采用光还原法将Ag纳米粒子负载到Bi_2WO_6催化剂表面.利用Ag良好的导电性以及表面plasma效应,有效增强了催化剂的可见光吸收,降低了光生载流子复合的几率,显著提高了污染物降解的光催化活性.同时确定了最佳Ag含量和反应条件.     

Theoretical investigation of Ag_n@(ZnS)_(42)(n=6-16) using first principles:Structural,electronic and optical properties

Ag@ZnS nanoparticles display enhanced photocatalytic efficiency and good photoelectric properties compared to their single-component counterparts in the process of forming a core-shell structure using an Ag cluster as the inner core of a ZnS outer shell.In this study,first-principles calculations were used to investigate the structural,electronic,and optical properties of Ag_n@(ZnS)_(42)(n=6-16)core-shell nanocomposites.The calculated results show significant even-odd oscillations in the structural stability,that is,Ag@ZnS nanostructures with an even number of Ag_n core atoms are relatively more stable than those with an odd number of core atoms.The secondorder differences in the total energies(Δ_2E)and the core-shell interaction energy E_(cs) indicate that a Ag_(12)@(ZnS)_(42)nanostructure is the most stable configuration.A significant red shift was found in Ag_n@(ZnS)_(42)nanoparticles in the absorption spectrum compared with a(ZnS)_(48) nanostructure,which is likely attributed to the strong electron interactions between the Ag core and the ZnS shell.     

Synthesis of AgI/Bi2MoO6 nano-heterostructure with enhanced visible-light photocatalytic property

A novel nano-heterostructure of Ag I/Bi_2MoO_6 photocatalyst was successfully synthesized via a facile depositionprecipitation method. The samples were systematically characterized by X-ray diffraction, scanning and transmission electron microscopy, X-ray photoemission spectroscopy, UV–Vis absorption spectroscopy, and photoluminescence spectra. While sole Bi_2MoO_6 or Ag I showed poor activity toward photocatalytic rhodamine B degradation, the nano-heterostructure was found with superior performance. The AgI/Bi_2MoO_6 composite with an optimal content of 20 wt% Ag I exhibited the highest photocatalytic degradation rate. Rhodamine B was totally degraded within 75 min visible-light irradiation. Moreover, the hybrid photocatalyst also showed a fairly good stability for several-cycle reuse. This study indicates that the AgI/Bi_2MoO_6 nano-heterostructure can be used as an effective candidate for photocatalytic degradation of organic pollutants.     

表面改性对含钛炉渣光催化性能的影响

以攀钢含钛高炉废渣为原料,掺杂不同比例稀硫酸,采用高能球磨复合无机改性低温煅烧的方法,合成了具有钙钛矿型的表面改性含钛炉渣催化剂(SMTBBFS).用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis)和热重(TG)分析对SMTBBFS催化剂进行了表征,确定其具有钙钛矿结构;煅烧后出现明显团聚现象,粉体的颗粒形态均为不规则块状;在紫外-可见区域具有较强的光吸收能力.由Cr(Ⅵ)的光催化还原率来评价稀硫酸不同掺杂比例对SMTBBFS催化剂光催化活性的影响.结果表明:硫酸掺杂比例为2.5%时,SMTBBFS催化剂由于存在较高的CaTiO3/TiO2晶相比、吸附容量以及适宜的表面酸性,而具有较高的光催化活性.     

新型AgBr/GO复合催化剂的制备及其可见光催化还原CO2性能的初步研究

 采用液相合成法,在十三烷基三甲基溴化铵（CTAB）辅助下制备具有可见光效应的AgBr/GO复合材料,并考察其在可见光下催化还原CO₂制备碳氢化合物的可行性及催化性能。XRD和TEM结果表明：AgBr纳米颗粒均匀地分散在GO载体表面,有利于光诱导下产生的电荷在AgBr与GO界面间的有效传递。可见光照射下,AgBr/GO复合催化剂还原CO₂生成的甲烷、甲醇、CO和乙醇的产量分别是106.11、64.20、26.53和10.96 μmol·g^-1,明显高于AgBr的催化活性。AgBr/GO在重复使用5次后其光催化还原CO₂的活性基本保持不变,因此AgBr/GO是一种高效的、光化学性质稳定的催化剂。     

八角中茴香油与莽草酸的提取和分离纯化

研究了用柱层析提取法从八角中提取、分离、纯化和制备高品质茴香油和高纯度莽草酸的方法.干燥的八角粉末过筛（250m～850m）,用85%乙醇柱层析提取法提取,收集材料干质量2.4倍体积的提取液,两者的提取率均超过93%.提取液减压蒸馏回收乙醇,分离油相和水相.油相经活性炭吸附等方法精制成高品质茴香油,总回收率93.2%,得率6.6%;水相经减压蒸干,用乙醇和石油醚处理除去杂质后,用乙醇结晶,得到纯度大于99%的莽草酸,总回收率为73.3%,得率为5.8%.     

复合光催化剂AgCl/AgBr降解水中四溴双酚A的研究

通过简单易行的沉淀工艺制造了具有优异光催化性能的AgCl/AgBr复合光催化剂. X射线衍射（XRD），扫描电子显微镜（SEM），能量色散X射线光谱（EDX）和紫外可见漫反射光谱对该材料的结晶结构、形貌特征和光吸收特性进行了表征，并且在可见光驱动下降解水中四溴双酚A (TBBPA). 结果表明，AgCl/AgBr具有优异的光催化活性，反应30 min后的降解率达98.49%，最后探讨了AgCl/AgBr复合材料可能的光催化机理,发现 ?OH和 ?O2 ? 是主要活性物质,并且在反应过程中有效地阻止了电子空穴对的复合,使材料表现出优异的光催化性能.     

Ag／TiO2中空纳米纤维结构材料的太阳光催化性能

利用一种模板辅助的两步法制备银修饰的TiO2中空纤维光催化纳米结构材料（Ag／TiO2）,借助于扫描电子显微镜（SEM）,X光电子能谱（XPS）,X线衍射（XRD）,uVvis光谱,Zeta电位等技术以及亚甲基蓝（MB）在不同光源条件下的降解脱色对目标材料结构、性能等进行了表征．结果表明：在空气气氛和适当温度下处理前驱材料（Ag＋-Ti4＋／CF）可以同时实现模板（CF）的去除,Ti4＋→TiO2和Ag＋→Ag的原位转化;材料的纳米纤维结构化和适量Ag（0．20％,质量分数）的引入有利于其太阳光催化性能的提高;该纤维材料易于分离,再利用．该纳米纤维结构材料良好的太阳光催化性能是众多因素协同作用的结果．