AgBr/TiO_2/硅藻土复合材料对罗丹明B光催化降解的研究

以硅藻土为载体,钛酸四丁酯为钛源,采用溶胶-凝胶法和沉淀-沉积法,制备了异质结结构的Ag Br/TiO_2/硅藻土复合材料,对罗丹明B(Rh B)污染物光催化降解。通过X射线衍射(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)、紫外-可见漫反射光谱(UV-Vis DRS)对复合材料晶型结构、形貌、元素化合价态和吸光性能表征分析。考察了不同摩尔比Ag Br/TiO_2对复合材料光催化性能的影响,并探究了复合材料的稳定性。结果表明,纳米TiO_2为锐钛矿晶型,Ag Br和TiO_2之间的异质结提高了复合材料的光催化活性;Ag Br和TiO_2摩尔比为0.20时,复合材料光催化活性最好。经过8次循环使用后,对Rh B的降解率仍保持在85%以上。     

AgBr/TiO_2/硅藻土复合材料对罗丹明B光催化降解的研究

以硅藻土为载体,钛酸四丁酯为钛源,采用溶胶-凝胶法和沉淀-沉积法,制备了异质结结构的Ag Br/TiO_2/硅藻土复合材料,对罗丹明B(Rh B)污染物光催化降解。通过X射线衍射(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)、紫外-可见漫反射光谱(UV-Vis DRS)对复合材料晶型结构、形貌、元素化合价态和吸光性能表征分析。考察了不同摩尔比Ag Br/TiO_2对复合材料光催化性能的影响,并探究了复合材料的稳定性。结果表明,纳米TiO_2为锐钛矿晶型,Ag Br和TiO_2之间的异质结提高了复合材料的光催化活性;Ag Br和TiO_2摩尔比为0.20时,复合材料光催化活性最好。经过8次循环使用后,对Rh B的降解率仍保持在85%以上。     

三维Ag/TiO_2纳米网的制备及其光催化性能研究

采用阳极氧化法在钛网上制备了TiO_2纳米管阵列,并利用循环伏安法在纳米管表面沉积Ag,制备出Ag/TiO_2纳米复合材料。采用扫描电子显微镜、X-射线衍射仪、紫外-可见漫反射光谱等方法对复合材料的形貌、结构、光电性能进行了表征,并以2,4-二硝基苯酚为模型化合物考察了沉积Ag对复合材料光催化性能的影响。结果表明,沉积5圈Ag的Ag/TiO_2复合纳米材料光催化性能最佳,在模拟太阳光照射120 min后,2,4-二硝基苯酚可被完全降解。     

Ag/Ag3PO4/TiO2双异质结催化剂的制备及光催化性能研究

通过紫外光诱导将Ag纳米颗粒沉积在Ag_3PO_4/TiO_2上,构建了Ag/Ag_3PO_4/TiO_2双异质结催化剂,通过废水中残留非那西丁(PNT)降解实验探究其光催化性能。结果表明,在紫外光照射下,以Ag/Ag_3PO_4/TiO_2为催化剂,当Ag_3PO_4质量分数为10%、催化剂用量为0.5 g·L~(-1)、初始pH值为9.0、PNT初始浓度为20 mg·L~(-1)时,PNT的降解效果最好,降解率最高可达97%。光致发光光谱显示,Ag的沉积导致Ag_3PO_4/TiO_2的光催化性能明显增强,对光生电子的转移产生积极作用,对电子-空穴对的复合产生抑制作用。     

Ag纳米粒子改性MoS_2/暴露(001)面TiO_2二维复合材料及其可见光催化性能研究

以钛酸四丁酯、氢氟酸、钼酸钠、硫代乙酰胺和硝酸银为原料,利用水热法和光沉积法成功在二硫化钼(MoS_2)/暴露(001)面TiO_2二维复合材料上沉积了银纳米粒子(Ag)。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、紫外可见吸收(UV-vis)对样品的相组成、表面形貌、表面元素组成和光响应范围进行表征测试,并在可见光下考察了复合材料降解亚甲基兰(MB)的光催化性能。结果表明粒径约为20~30 nm的Ag颗粒成功负载在MoS_2/暴露(001)面的TiO_2纳米片上(MT-001),Ag纳米粒子的等离子共振效应有效的改善了MT-001纳米片的光催化性能,改性后复合材料对MB的最佳降解率为89.72%,为同等条件下纯TiO_2纳米片的1.55倍。     

Ag/TiO_2纳米片异质结薄膜的制备及清除NO_x的性能研究

采用微波辅助化学还原法制备Ag/TiO_2纳米片异质结薄膜光催化剂,通过XRD、SEM、UV-Vis、PL和光电流响应对其进行表征,并考察了其清除气相中氮氧化物(NOx)的性能。结果表明,Ag/TiO_2 NSF光催化剂对光的吸收利用好,光生载流子复合几率小,其光催化清除NO_x的活性比TiO_2 NSF高,其中1.0 Ag/TiO_2NSF的效果最好。     

沉淀-光还原法制备Ag@AgCl/TiO2及其光催化性能

首先采用沉淀法在TiO_2表面上沉积AgCl制得AgCl/TiO_2,然后在氙灯下照射90 min将AgCl部分光还原成Ag~0合成了Ag@AgCl/TiO_2光催化剂。对样品进行紫外-可见光漫反射光谱(UV-Vis DRS)和光致发光光谱(PL)测试,结果显示Ag@AgCl/TiO_2光催化剂的禁带宽度和光致发光强度明显降低,说明其具有较强的可见光吸收能力并且明显降低了光生电子-空穴的复合率。在可见光的照射下,Ag@AgCl/TiO_2复合光催化剂在30 min内对罗丹明B模拟污染物的降解率为99.5%。     

三维In_2S_3/TiO_2纳米复合材料的制备及光电性能

采用阳极氧化法在钛网基底上制备出TiO_2纳米管阵列,利用连续离子层吸附法(SILAR)将半导体In_2S_3沉积到TiO_2纳米管表面,制备In_2S_3/TiO_2纳米复合材料。利用扫描电子显微镜(SEM)、X-射线衍射仪(XRD)及紫外-可见漫反射光谱(DRS)对材料的形貌和结构进行表征,并通过荧光光谱仪以及光电信号对不同沉积圈数的In_2S_3/TiO_2纳米复合材料的光电性能进行测试。结果表明,制备的In_2S_3纳米颗粒均匀沉积在TiO_2纳米管上,并且不会堵塞纳米管的管孔。沉积不同圈数的In_2S_3/TiO_2纳米复合材料表现出不同的光电化学性质。     

壳聚糖/纳米TiO_2对淀粉复合膜性能的影响

以马铃薯淀粉为基材,壳聚糖和纳米TiO_2为增强相,研究壳聚糖和纳米TiO_2对马铃薯淀粉成膜性能的影响。通过溶液共混法将壳聚糖的乙酸溶液与马铃薯淀粉糊化液,按照4∶6的比例均匀混合,加入纳米Ti O2流延成膜,研究壳聚糖和纳米TiO_2对复合膜的阻氧性及透湿性的影响;用XRD、SEM表征复合膜的结构与形态。研究结果表明,马铃薯淀粉与壳聚糖、纳米TiO2组分成膜时具有良好的相容性;壳聚糖和纳米TiO_2能有效改善复合膜的水蒸气透过性和阻氧性;纳米TiO_2/壳聚糖/马铃薯淀粉复合膜较马铃薯淀粉单膜、马铃薯淀粉/壳聚糖复合膜、马铃薯淀粉/纳米TiO_2复合膜的阻氧性提高了43. 38%、7. 56%、19. 14%;水蒸气透过率降低了32. 41%、39. 18%、30. 89%。壳聚糖和纳米TiO_2添加到马铃薯淀粉液中共混制膜,能够增强复合膜的性能。     

Ag/TiO_2纳米复合材料的制备及抗菌性能研究

以二氧化钛为前驱体,采用纯有机均相沉积法制备不同Ag负载量的Ag/TiO_2纳米复合材料;采用XRD分析手段对纳米Ag/TiO_2复合材料进行表征,并研究了Ag/TiO_2复合材料的抗菌性能。采用菌落计数法探索载银量对大肠杆菌的抗菌性能的影响,得到最佳银负载量为2.5%,同时,表明该抗菌材料具有良好的抗菌持久性。     

Green Synthesis and Characterization of Silver/Chitosan/Polyethylene Glycol Nanocomposites without any Reducing Agent

This paper presents the green synthesis of silver nanoparticles (Ag NPs) in aqueous medium. This method was performed by reducing AgNO(3) in different stirring times of reaction at a moderate temperature using green agents, chitosan (Cts) and polyethylene glycol (PEG). In this work, silver nitrate (AgNO(3)) was used as the silver precursor while Cts and PEG were used as the solid support and polymeric stabilizer. The properties of Ag/Cts/PEG nanocomposites (NCs) were studied under different stirring times of reaction. The developed Ag/Cts/PEG NCs were then characterized by the ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy.     

Preparation of silver nanoparticles using chitosan suspensions

Silver/chitosan nanocomposites were prepared by using basic chitosan suspension as a stabilizer and as a reductant in the absence of other chemicals. The size and distribution of the resulting nanocomposite were strongly dependent on the concentration of chitosan and sodium hydroxide. UV-vis spectra and analytical electron microscopy (AEM) revealed the presence of silver/chitosan nanocomposites. In addition, Ag nanoparticles were obtained by annealing silver/composites at 600 °C. These nanoparticles were characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectrometry (EDS). The FESEM indicated that the size of a majority of the Ag nanoparticles ranged between 10 and 150 nm. A change in the nanoparticles to porous-like nanostructures was observed when the composite feeding amount was increased, the annealing time prolonged, and the reaction temperature elevated.     

Laser-Induced Silver Nanoparticles on Titanium Oxide for Photocatalytic Degradation of Methylene Blue

Silver nanoparticles doped on titanium oxide (TiO₂) were produced by laser-liquid interaction of silver nitrate (AgNO₃) in isopropanol. Characteristics of Ag/TiO₂ (Ag doped TiO₂) nanoparticles produced by the methods presented in this article were investigated by XRD, TEM, SEM, EDX, and UV-Vis. From the UV-Vis measurements, the absorption of visible light of the Ag/TiO₂ photocatalysts was improved (additional absorption at longer wavelength in visible light region) obviously. The photocatalytic efficiency of Ag/TiO₂ was tested by the degradation of methylene blue (MB) in aqueous solution. A maximum of 82.3% MB degradation is achieved by 2.0 wt% Ag/TiO₂ photocatalyst under 2 h illumination with a halogen lamp.     

Radiation synthesis, characterisation and antimicrobial application of novel copolymeric silver/poly(2-hydroxyethyl methacrylate/itaconic acid) nanocomposite hydrogels

Silver nanoparticles were fabricated via in situ reduction of silver nitrate embedded in swollen P(HEMA/IA) hydrogel, using gamma radiolysis method. Copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA), previously synthesised by gamma radiation for wound dressing application, were used as a carrier and a stabilising agent, while ethyl alcohol was used as a free radical scavenger. The influence of different P(HEMA/IA) hydrogels and silver salt concentrations on the size and distribution of nanoparticles was investigated. The Ag/P(HEMA/IA) nanocomposites were characterised by high resolution scanning electron microscopy, energy dispersive spectroscopy, wide-angle X-ray diffraction, UV-Vis spectroscopy and swelling measurements. Escherichia coli (Gram-negative bacterium), Staphylococcus aureus (Gram-positive bacterium) and Candida albicans (fungus) were used to prove the antimicrobial properties of Ag/P(HEMA/IA) nanocomposites. The inhibition kinetics of bacteria growth was investigated by measuring the colony-forming unit. The antimicrobial effectiveness of the Ag/P(HEMA/IA) hydrogel nanocomposite was demonstrated even at small silver concentrations. P(HEMA/IA) hydrogels containing nanosilver particles was found suitable to be used as wound dressing.     

负载有Ag纳米粒子的TiO2准一维复合材料制备及其SERS效应

采用紫外光还原法和种子法制得了不同含量Ag纳米粒子负载的锐钛矿型TiO2纳米带复合材料。用各种测试技术对产物的物相、形貌、Ag负载情况以及SERS性质进行了一系列表征。测试结果表明,以紫外光还原法获得的产物中Ag完全负载在TiO2纳米带表面,其粒径主要处在10～50 nm间,且Ag负载量随着还原次数增多而缓慢增加。在此基础上,以种子法制得的产物中Ag负载量则显著增大,覆盖率可达80 %以上。这种含Ag纳米复合材料具有检测吡啶分子的SERS活性,其Ag负载量越多,SERS效应越明显。     

Chitosan/poly(dimethylaminoethylmethacrylate-co-hydroxyethylacrylate) based semi-IPN hydrogels and silver nanocomposites: Synthesis,evaluation of amoxicillin release studies,and antibacterial studies

To fabricate new smart materials that can deliver both the pharmaceutically active molecules and metal nanoparticles, we have formulated chitosan-based semi-IPN hydrogels and their silver nanocomposites (Ag NCs) along with amoxicillin (AMX). Semi-IPN hydrogels and their Ag NCs were synthesized from chitosan, dimethylamino ethyl methacrylate and 2-hydroxyethyl methacrylate via simple-free radical polymerization method and reducing with NaBH₄. The resultant formulations were evaluated for in vitro release of AMX, anti-bacterial studies and DNA cleavage studies. The hydrogels with AMX-derived silver nanoparticles (Ag NPs) show better ability to cleave DNA and anti-microbial activity than individual AMX and Ag NPs.     

Preparation of Silver Nanoparticles/Pseudo-Thermoplastic Polyvinyl Alcohol (PT-PVA) Films by the Synchronous Chemical Reduction Method

To prevent the evident agglomeration of silver nanoparticles during processing, this study reduced silver nanoparticles in pseudo-thermoplastic polyvinyl alcohol (PT-PVA) water solutions using the synchronous chemical reduction method. The PT-PVA coating could protect the silver nanoparticles to avoid agglomeration, allowing the silver nanoparticles to disperse uniformly in the PT-PVA. According to the particle size, TEM and UV-Vis analyses, the reduction of silver nanoparticles in PT-PVA solutions produced silver nanoparticles/PT-PVA films that had small particle size without agglomeration. Conversely, silver nanoparticles were added directly into PT-PVA, tended to have obvious agglomeration during the preparation process.     

银纳米颗粒及其负载TiO2的制备与应用研究

采用液相化学还原法和溶胶-凝胶法,制备得到形貌各异的银颗粒及其负载的TiO2复合材料。透射电镜（TEM）结果显示,可以制备得到表面光滑,形状均匀一致的球形、三角形和四方形银纳米颗粒;X射线衍射（XRD）结果表明,银纳米颗粒晶体结构属于立方品系;利用傅立叶变换红外光谱仪（FT—IR）研究了聚乙烯吡咯啉酮（PVP）在生成不同形貌银纳米颗粒的化学反应中的作用机理;Ag／TiO2复合材料的X射线衍射能谱（XPS）结果表明,负载的银主要以零价态形式存在于TiO2的表面;研究了不同形貌银纳米颗粒的抗菌性能以及Ag／TiO2复合材料的光催化脱色亚甲基蓝的活性,结果表明,所制备的银纳米颗粒杀菌率均在99％以上;银负载到TiO2后,Ag／TiO2复合材料的光催化活性得到明显提高。其中,球形银负载的Ag／TiO2复合光催化剂活性最好。     

导电高分子PEDOT／PSS保护银纳米颗粒的制备与表征

利用导电高分子聚（3，4-二氧乙基噻吩）／聚（对苯乙烯磺酸）（PEDOT／PSS）作保护剂，制备了银纳米颗粒，用UV-Vis和TEM对其进行了表征．结果表明，选择合适量的PEDOT／PSS保护剂可以得到大小分布较窄银纳米颗粒．     

Preparation and Characterization of Gelatin Nanofibers Containing Silver Nanoparticles

Ag nanoparticles (NPs) were synthesized in formic acid aqueous solutions through chemical reduction. Formic acid was used for a reducing agent of Ag precursor and solvent of gelatin. Silver acetate, silver tetrafluoroborate, silver nitrate, and silver phosphate were used as Ag precursors. Ag⁺ ions were reduced into Ag NPs by formic acid. The formation of Ag NPs was characterized by a UV-Vis spectrophotometer. Ag NPs were quickly generated within a few minutes in silver nitrate (AgNO₃)/formic acid solution. As the water content of formic acid aqueous solution increased, more Ag NPs were generated, at a higher rate and with greater size. When gelatin was added to the AgNO₃/formic acid solution, the Ag NPs were stabilized, resulting in smaller particles. Moreover, gelatin limits further aggregation of Ag NPs, which were effectively dispersed in solution. The amount of Ag NPs formed increased with increasing concentration of AgNO₃ and aging time. Gelatin nanofibers containing Ag NPs were fabricated by electrospinning. The average diameters of gelatin nanofibers were 166.52 ± 32.72 nm, but these decreased with the addition of AgNO₃. The average diameters of the Ag NPs in gelatin nanofibers ranged between 13 and 25 nm, which was confirmed by transmission electron microscopy (TEM).