Cu@rGO纳米复合材料的制备及催化性能

采用一步还原法制备Cu@rGO纳米复合材料,通过透射电镜(TEM)、X射线衍射(XRD)、傅里叶红外光谱(FTIR)和X射线光电子能谱(XPS)等方法对Cu@rGO纳米复合材料的结构和形貌等进行了表征,并采用紫外-可见吸收光谱法(UV-Vis),以有机染料罗丹明B(RhB)为模拟污染物考察了其在NaBH4作用下的催化降解性能。结果表明,原料配比rGO:Cu=1:3时,制备的Cu@rGO复合材料中纳米铜呈类球型颗粒,具有极小的纳米尺寸(2.10nm)且粒径分布窄,染料降解实验表明rGO:Cu=1:3的Cu@rGO纳米复合材料对RhB催化降解效果显著,且经过6次循环使用后,其催化活性没有明显变化。     

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。     

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。     

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。     

CoO/CdS纳米复合材料的制备及其光催化降解亚甲基蓝的研究

采用物理气相沉积法制备CoO/CdS纳米复合材料,通过扫描电子显微镜(SEM)、X射线衍射仪(XRD)、X射线能谱仪(E DS)和紫外-可见分光光度计(UV-Vis)对其形貌、结构和光吸收性质进行表征,并以亚甲基蓝溶液的光催化降解为探针反应,在可见光下考察CoO/CdS纳米复合材料的光催化性能.结果表明,CoO/CdS纳米复合材料的光催化活性显著高于CdS纳米颗粒,100 min后亚甲基蓝降解率达到92.4％.     

Ag@AgCl/Mg-Al-LDHs复合光催化剂的制备及可见光催化活性

采用过饱和沉淀法制备了镁铝层状双金属氢氧化物(Mg-Al-LDHs)载体,再以Ag NO3和HCl通过沉积-沉淀法制得Ag Cl/Mg-Al-LDHs,光还原后得到了可见光响应和高活性的Ag@Ag Cl/Mg-Al-LDHs等离子体共振光催化剂。采用XRD,SEM,TG-DTG,FT-IR和BET等技术对催化剂的相结构和微观形貌等进行了表征。结果表明:Mg-AlLDHs因其较大的负载表面使得负载的Ag@Ag Cl纳米粒子颗粒变小、分散程度增强,这不仅增加了复合材料的活性位点,而且提高了负载Ag@Ag Cl纳米颗粒的光生电子-空穴对的氧化-还原能力,从而使得复合材料具有比Ag@Ag Cl更高的反应活性。在可见光条件下(λ420 nm),Ag@Ag Cl/Mg-Al-LDHs复合材料光催化降解亚甲基蓝(MB)的活性明显高于纯Ag@Ag Cl,当Ag@Ag Cl的负载量(质量分数)为16%时表现出最好的光催化活性,可见光照射10 mg/L MB溶液180 min的光解率达96.04%。     

碳微球负载Ag_3PO_4的合成与其光催化性能

以碳微球(CMSs)为载体,采用离子交换法制备了CMSs负载的磷酸银复合材料(CMSs/Ag3PO4)。对合成的CMSs/Ag3PO4复合材料的相组成、表面形貌和紫外-可见(UV-Vis)吸收光谱进行了表征,通过可见光催化降解甲基橙实验对所制备的CMSs/Ag3PO4复合材料的光催化活性进行了考察。结果表明:CMSs颗粒大小在100~200 nm,CMSs/Ag3PO4颗粒大小在200~250 nm;CMSs/Ag3PO4在可见光范围有强吸收,在可见光照射下,CMSs/Ag3PO4能有效地降解甲基橙,光照射60min对甲基橙的降解率可以达到92.5%;循环使用5次后,对甲基橙的降解率仍然保持为86.2%。     

Ag/Fe_3O_4磁性复合材料的生物合成及光催化性能研究

用金属还原菌Shewanella oneidensis MR-1在Fe_3O_4微球表面原位还原Ag+形成了Ag/Fe_3O_4磁性复合材料。采用HRTEM、XRD、VSM、XPS对Ag/Fe_3O_4的结构和性能进行表征。结果表明:银纳米颗粒(约15 nm)较为均匀分散在Fe_3O_4微球(约380 nm)表面;在可见光照射下,Ag/Fe_3O_4具有较高的催化活性,50 min内对亚甲基蓝的降解率可达96.3%,较未负载Ag的Fe_3O_4微球的降解率提高了20.3%。Ag/Fe_3O_4在室温下呈现超顺磁性,饱和磁强度为34.9 emu/g,在外加磁场条件下能快速从溶液中分离;且复合材料表现出较好的循环稳定性,6次循环后其催化活性无明显变化。     

Ag/AgBr/Bi_2MoO_6等离子体光催化剂的制备及其降解罗丹明B性能的研究

通过简单的溶剂热-原位沉积-光致还原法成功合成了一种新型等离子体光催化剂Ag/AgBr/Bi_2MoO_6。利用X射线衍射、X射线光电子能谱、扫描电镜、透射电镜和高分辨透射电镜、紫外-可见漫反射光谱和荧光光谱对Ag/AgBr/Bi_2MoO_6催化剂的物理性质和光物理性质进行表征和分析。研究了Ag/AgBr/Bi_2MoO_6复合材料对罗丹明B的光催化降解活性。结果表明,Ag/AgBr质量分数为30%时光催化性能最优,其复合材料的光催化效率是纯Bi_2MoO_6的6.4倍。Ag/AgBr/Bi_2MoO_6复合材料的高活性主要归因于协同作用诱导的光生电子-空穴对的有效分离。基于Ag纳米粒子表面的等离子体共振效应理论,探讨了Ag/AgBr的引入改善Bi_2MoO_6光催化活性可能的机理。     

g-C_3N_4/C/Ag复合材料的制备及其光催化性能的影响

为了提高石墨型氮化碳(g-C_3N_4)的光催化性能,通过水热还原法制备了g-C_3N_4/C/Ag纳米复合材料,并用扫描电子显微镜(SEM),X射线衍射仪(XRD)和高分辨率傅立叶变换红外(FTIR)光谱表征了产品的微观形貌和化学组成。产品的紫外可见光吸收光谱分析表明,加入的纳米银可以提高复合材料的光吸收范围和可见光的吸收强度。用制备得到的四种样品进行了亚甲基蓝的降解实验,发现当反应条件为180℃,反应时间为6 h时,得到的g-C_3N_4/C/Ag纳米复合材料的光催化降解性能最好。表明成功制备出了g-C_3N_4/C/Ag纳米复合材料,其光催化性能比g-C_3N_4更强。     

TiO<Subscript>2</Subscript> porous ceramic/Ag–AgCl composite for enhanced photocatalytic degradation of dyes under visible light irradiation

TiO₂ porous ceramic/Ag–AgCl composite was prepared by incorporating AgCl nanoparticles within the bulk of TiO₂ porous ceramic followed by reducing Ag⁺ in the AgCl particles to Ag⁰ species under visible light irradiation. The porous TiO₂ ceramic was physically robust and chemically durable, and the porous structure facilitated the implantation of AgCl NPs. Compared with the bare TiO₂ ceramic, TiO₂ porous ceramic/Ag–AgCl composite exhibited higher photocatalytic performance for the degradation of MO and RhB under visible light irradiation. The reaction rate constants k of MO and RhB degradation over TiO₂ porous ceramic/Ag–AgCl composite was respectively 6.25 times and 3.62 times higher than those recorded over the bare TiO₂ porous ceramic. The photocatalytic activity showed virtually no decline after four times cyclic experiments under visible light irradiation. Scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, photoluminescence spectra and X-ray photoelectron spectroscopy were used to characterize the TiO₂ porous ceramic/Ag–AgCl composite.     

可见光响应的壳-核结构Ag/AgCl光催化剂性能

利用光化学还原法制备了Ag/AgCl壳-核结构的复合纳米粒子,以亚甲基蓝为模型降解物,研究了其可见光催化性能。结果表明,壳-核结构的Ag/AgCl纳米材料具有表面等离子效应,提高了其对可见光吸收和光催化活性。在可见光照射下,亚甲基蓝溶液浓度为10 mg·L^-1,催化剂用量10 mg·L^-1,光照60 min,亚甲基蓝降解率达95%,COD去除率为92%。     

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.     

Synthesis and intercalation of silver nanoparticles in kaolinite/DMSO complexes

Ag nanoparticles were synthesized in the interlamellar space of a layered kaolinite. Disaggregation of the lamellae of the nonswelling kaolinite was achieved by the intercalation of dimethyl sulfoxide (DMSO). The kaolinite was suspended in aqueous AgNO₃ solution and the adsorbed Ag⁺ ions were reduced on the surface of kaolinite lamellae with NaBH₄ or UV light irradiation. The silver nanoparticles formed were characterized by X-ray diffraction (XRD), small angle X-ray scattering (SAXS), and transmission electron microscopy (TEM). We studied the effects of the two reduction methods on the size and the size distribution of Ag nanoparticles and how clay mineral structure is altered as a consequence of particle formation. It was established that the size of Ag nanoparticles depends on both silver content and the reduction method. Photoreduction of silver led to the formation of relatively large Ag nanoparticles (diameter 8–14 nm).     

CdS/TiO2复合纳米粒子的制备及其产氢性能研究

采用化学沉淀法制备了CdS包覆TiO2（CdS/TiO2）复合纳米粒子,利用XRD、TEM、SEM、UV-vis吸收光谱等对其进行了表征分析,并以可见光分解水制氢为探针反应考察了复合纳米粒子的活性。结果表明,CdS/TiO2 复合纳米粒子的颗粒大小约为40nm,TiO2 以锐钛矿型存在,CdS以六方相存在;复合纳米粒子的吸收光谱较TiO2 发生“红移”,大幅拓宽了对可见光区的吸收范围。光解水制氢实验表明,CdS/TiO2 复合纳米粒子具有良好的可见光释氢活性和光学稳定性。     

AgBr/ZnO复合材料光催化剂及其光催化性能

通过一步水热法制备了AgBr/ZnO复合光催化剂,并采用扫描电子显微镜、透射电子显微镜、X射线衍射仪、X射线光电子能谱仪、紫外–可见光漫反射光谱仪和光致发光光谱仪对样品进行表征,分析了AgBr/ZnO体系的合成对材料光催化性能的影响。以罗丹明B溶液为目标污染物,研究复合催化剂的光催化活性。结果表明:在制备的复合样品中,Ag Br与ZnO摩尔比为1:5时(AgBr/ZnO-2)光催化活性最好,在可见光照射下,60 min对罗丹明B的降解率可达98.98%,相比于ZnO光催化活性明显提升,降解速率常数提升了11.08倍;与商用TiO2(P25)相比,降解速率常数提升了10.14倍,这主要归因于Ag Br/ZnO拥有比ZnO更低的电子空穴复合概率,且复合催化剂的光学吸收带边发生红移,从而增强了对可见光的吸收。     

Studies on the synthesis of electrospun PAN‐Ag composite nanofibers for antibacterial application

We have successfully synthesized polyacrylonitrile (PAN) nanofibers impregnated with Ag nanoparticles by electrospinning method at room temperature. Briefly, the PAN‐Ag composite nanofibers were prepared by electrospinning PAN (10% w/v) in dimethyl formamide (DMF) solvent containing silver nitrate (AgNO₃) in the amounts of 8% by weight of PAN. The silver ions were reduced into silver particles in three different methods i.e., by refluxing the solution before electrospinning, treating with sodium borohydride (NaBH₄), as reducing agent, and heating the prepared composite nanofibers at 160°C. The prepared PAN nanofibers functionalized with Ag nanoparticles were characterized by field emission scanning electron microscopy (FESEM), SEM elemental detection X‐ray analysis (SEM‐EDAX), transmission electron microscopy (TEM), and ultraviolet‐visible spectroscopy (UV‐VIS) analytical techniques. UV‐VIS spectra analysis showed distinct absorption band at 410 nm, suggesting the formation of Ag nanoparticles. TEM micrographs confirmed homogeneous dispersion of Ag nanoparticles on the surface of PAN nanofibers, and particle diameter was found to be 5–15 nm. It was found that all the three electrospun PAN‐Ag composite nanofibers showed strong antibacterial activity toward both gram positive and gram negative bacteria. However, the antibacterial activity of PAN‐Ag composite nanofibers membrane prepared by refluxed method was most prominent against S. aureus bacteria. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Hierarchically plasmonic photocatalysts of Ag/AgCl nanocrystals coupled with single-crystalline WO(3) nanoplates

The hierarchical photocatalysts of Ag/AgCl@plate-WO(3) have been synthesized by anchoring Ag/AgCl nanocrystals on the surfaces of single-crystalline WO(3) nanoplates that were obtained via an intercalation and topochemical approach. The heterogeneous precipitation process of the PVP-Ag(+)-WO(3) suspensions with a Cl(-) solution added drop-wise was developed to synthesize AgCl@WO(3) composites, which were then photoreduced to form Ag/AgCl@WO(3) nanostructures in situ. WO(3) nanocrystals with various shapes (i.e., nanoplates, nanorods, and nanoparticles) were used as the substrates to synthesize Ag/AgCl@WO(3) photocatalysts, and the effects of the WO(3) contents and photoreduction times on their visible-light-driven photocatalytic performance were investigated. The techniques of TEM, SEM, XPS, EDS, XRD, N(2) adsorption-desorption and UV-vis DR spectra were used to characterize the compositions, phases and microstructures of the samples. The RhB aqueous solutions were used as the model system to estimate the photocatalytic performance of the as-obtained Ag/AgCl@WO(3) nanostructures under visible light (λ≥ 420 nm) and sunlight. The results indicated that the hierarchical Ag/AgCl@plate-WO(3) photocatalyst has a higher photodegradation rate than Ag/AgCl, AgCl, AgCl@WO(3) and TiO(2) (P25). The contents and morphologies of the WO(3) substrates in the Ag/AgCl@plate-WO(3) photocatalysts have important effects on their photocatalytic performance. The related mechanisms for the enhancement in visible-light-driven photodegradation of RhB molecules were analyzed.     

碳量子点修饰g-C3N4/SnO2复合材料光催化性能

以四氯化锡五水合物、乙二醇和氨水为原料,在微波辅助水热条件下快速合成氧化锡纳米颗粒,以尿素 为前体在马弗炉中退火得到g-C₃N₄,使用柠檬酸和乙二胺为原料水热合成碳量子点。室温下,将碳量子点/ g-C₃N₄/SnO₂在通风橱中进行搅拌得到碳量子点负载的氮化碳/氧化锡复合材料。通过透射电子显微镜（TEM）、 X射线衍射（XRD）、氮气吸附-解吸等温线（BET）、紫外-可见分光光度计（UV-vis）、电子自旋（顺磁）共振波谱仪（ESR）对复合材料的形貌、结构特征、吸光度和光催化过程中的活性物质等进行表征和分析,并通过在紫外光下降解罗丹明B（RhB）测试样品的光催化性能。试验结果表明,紫外-可见分光光谱吸收边缘的红移说明碳量子点负载后能提高复合材料在可见光区域的响应,光催化试验表明碳量子点负载能提高g-C₃N₄/SnO₂复合材料的光催化性能,当碳量子点负载量为7%时复合材料的降解效率最高,在3h内对RhB的降解效率为97%。此外,微波辅助水热法能在短时间内大量合成氧化锡纳米颗粒,且氧化锡纳米颗粒具有较小的晶粒尺寸（8.5nm）,可以高效制备并应用于环保领域。     

Ag NPs改性鱼鳞明胶-琼脂复合膜的制备及性能表征

利用鱼鳞明胶作为还原剂和稳定剂制备银纳米颗粒（silver nanoparticles, Ag NPs），研究Ag NPs添加量（0.04wt%-0.2wt%）对鱼鳞明胶-琼脂复合膜的理化性能和抗菌性能的影响。通过透射电子显微镜和X射线粉末衍射对合成的Ag NPs进行表征，结果表明制得Ag NPs为球形形貌，平均粒径为9.3 ?1.8 nm。随着Ag NPs添加量的增加，鱼鳞明胶-琼脂复合膜的色泽变黄渐深，透明度下降，对紫外和可见光的吸收增强，同时，复合膜的断裂延展性、水蒸气阻隔性能和耐水性能显著增强，而厚度和抗拉强度却无明显变化。FTIR和热重分析结果表明，Ag NPs与膜基质间存在化学相互作用，并在一定程度上改善了复合膜的热稳定性。抑菌环实验结果显示，复合膜可以在0.04wt%-0.2wt%较低的银浓度下实现良好的抗菌效果。研究结果将为鱼鳞明胶可降解抗菌包装材料的开发提供新思路。