ZnO/CdS/Ag复合光催化剂的制备及其催化和抗菌性能

先用水热反应合成六方晶相CdS多层级花状微球并在其表面生长ZnO纳米棒形成均匀的ZnO/CdS复合结构,然后用光还原法将Ag纳米颗粒负载于ZnO纳米棒制备出ZnO/CdS/Ag三元半导体光催化剂,对其进行扫描电镜和透射电镜观察、光电性能测试、活性基团捕获实验以及光催化降解和抗菌性能测试,研究其对亚甲基蓝(MB)的降解和抗菌性能。结果表明：ZnO纳米棒均匀生长在CdS微球表面,CdS晶体没有明显裸露,Ag纳米粒子负载在ZnO纳米棒的表面;ZnO/CdS/Ag三元复合光催化剂有良好的可见光响应、较低的阻抗和较高的光电流密度;ZnO/CdS/Ag复合光催化剂能同时产生羟基和超氧自由基等活性氧基团;ZnO/CdS/Ag三元复合光催化剂对亚甲基蓝(MB)的30 min降解率高于90%;0.25 mg/mL的ZnO/CdS/Ag对革兰氏阴性菌(大肠杆菌)的灭菌率高于96%,对革兰氏阳性菌(金黄色葡萄球菌)能完全灭除。     

PVP为偶联剂制备核壳型PS/CdS纳米复合粒子及表征

以聚乙烯吡咯烷酮(PVP)为偶联剂,利用超声化学法制备了PS/CdS核壳型复合纳米粒子。为了深入理解核壳型纳米粒子的界面行为和形成机制,详细考察了PVP加入与否及用量、前体加入顺序、Cd2+与S2-摩尔比和反应时间等实验参数对核壳复合材料结构的影响。结果表明,适量PVP可改善CdS纳米粒子与PS聚合物基体间的亲和性,增强壳与核之间的相互作用,成功地将PS与CdS复合成单分散的、壳层完整且厚度可控的三维核壳型PS/CdS纳米复合粒子;且复合物比纯CdS粒子具有更高的可见光响应活性。     

介孔氧化硅/氧化铈核壳双相复合颗粒的制备及其光催化降解活性

将CeO₂纳米粒子负载在介孔氧化硅(W-mSiO₂)支撑体上,制备了核壳结构的W-mSiO₂/CeO₂双相光催化复合颗粒。用X射线衍射、扫描电镜、透射电镜、氮气吸脱附、STEM-EDX mapping、Raman光谱、荧光光谱、紫外-可见漫反射光谱等手段分析样品的结构和性质,考察了复合光催化材料对亚甲基蓝(MB)的光催化降解反应活性。结果表明,复合颗粒中介孔氧化硅内核的尺寸为180~200 nm、比表面积高达1627 m²/g,包覆层(厚度约20 nm)由大量尺寸为数纳米的氧化铈粒子组成。介孔内核对MB有较强的吸附能力,使之富集在CeO₂活性粒子周围,从而提高了复合颗粒对MB的光催化降解效果。对壳层CeO₂纳米粒子进行Er³⁺掺杂改性并在非氧化性气氛(氮气)中保护煅烧,有助于进一步提高复合颗粒对MB的光催化降解活性。     

核壳结构CdS/ZnS荧光量子点的制备与荧光性能研究

以氧化镉为镉源、硫单质为硫源、油酸为配体、在十八烯体系中合成单分散的CdS纳米颗粒,研究了配体浓度对纳米微粒的生长动力学、颗粒尺寸分布的影响.采用乙基黄原酸锌作为Zn、S源的反应前体,采用逐滴滴加的方法制备了具有核壳结构的CdS/ZnS量子点,吸收光谱和荧光光谱表明CdS/ZnS纳米粒子比单一的CdS纳米粒子具有更优异的发光特性.透射电子显微镜、X射线粉末衍射、X射线光电子能谱、选区电子衍射证明ZnS在CdS表面进行了有效包覆.所制备核壳结构纳米粒子具有较好的尺寸分布,荧光发射峰半高峰宽为18～20nm,荧光量子产率达40%.     

中空CdS/ZnS纳米核壳材料的制备及其光催化性能探究

采用化学浴法制备聚苯乙烯(PS)/CdS纳米核壳材料,在超声波的作用下采用化学浴法制备PS/CdS/ZnS纳米核壳材料,最后溶液刻蚀除去中心模板,得到中空的CdS/ZnS核壳材料。利用SEM、TEM、EDX、XRD和UV-Vis等测试手段对样品的形貌、成分、粒度、微观结构和吸光度等进行了表征。结果表明:该方法制备的CdS/ZnS纳米材料具有空心双壳层结构,颗粒大小均匀,内壳层厚度为85~100nm,外壳层厚度约为40nm,在可见光下具有良好的稳定催化效能,能够多次回收循环利用。     

Cu2O-PVA/纳米纤维素复合材料的制备与吸附—光催化性能

为了改善氧化亚铜(Cu₂O)的光催化性能,将Cu₂O颗粒和聚乙烯醇(PVA)同时加入纳米纤维素(CNF)中,成功制备了具有三维(3D)多孔结构和丰富活性位点的功能化纤维素基气凝胶(Cu₂O-PVA/CNF)。采用扫描电子显微镜、傅里叶变换红外光谱、X射线衍射仪、全自动比表面积、压缩测试对气凝胶样品进行了表征。以降解亚甲基蓝(MB)为模型污染物,评价了Cu₂O-PVA/CNF复合催化剂的光催化性能,考察了6wt%Cu——2O-PVA/CNF在不同初始浓度、不同催化剂用量及不同溶液pH条件下对MB光降解效率的影响。结果表明,三维多孔的纤维素气凝胶的使用提高了对MB的吸附能力,延长了对可见光的吸收。特别是在纤维素基体中掺杂的Cu₂O在光照下激发出电子-空穴,增加了活性位点,从而提高了催化能力。6wt%Cu₂OPVA/CNF复合催化剂对MB的光降解率达到95.6%,远高于纯Cu₂O的79.6%。Cu₂O-PVA/CNF复...     

核壳结构CdS：Mn/ZnS纳米晶的制备与光学性能研究

以3-巯基丙酸为稳定剂,采用共沉淀法在水相中合成了CdS∶Mn掺杂纳米晶,然后进一步将ZnS包覆于CdS∶Mn纳米晶表面,制备了CdS∶Mn/ZnS核壳结构纳米晶。利用X射线衍射（XRD）,透射电子显微镜（TEM）和紫外-可见吸收光谱（UV-Vis）对纳米晶的结构、形貌和光学性质进行了表征,发现制备的纳米晶具有优秀的单分散性,确认合成了CdS∶Mn/ZnS核壳结构纳米晶。通过荧光光谱（PL）研究了纳米晶的发光性质和光稳定性,结果表明包覆壳层后纳米晶的发光强度显著提高,最高可达8倍,且Mn2＋离子的发光峰峰位置随着ZnS壳层数的增加而红移。此外,核壳纳米晶的光稳定性大大提高。     

壳聚糖-CdS复合纳米粒子对甲基橙的光催化降解作用

用反相微乳液法制备了壳聚糖-CdS复合纳米粒子,并考察了复合纳米粒子用量、光照条件和溶液pH值等因素对光催化降解甲基橙的影响.结果表明:在100 mL质量浓度为20 mg/L的甲基橙溶液中加入0.30 g复合纳米粒子,可以达到较好的光催化降解效果;甲基橙在光催化降解过程中最大吸收波长464 nm处的吸收峰迅速减弱,并最终消失,且在258 nm和455 nm处出现了新的吸收峰,说明甲基橙发生了降解;溶液pH值对光催化降解甲基橙有一定的影响,在弱酸性条件下降解效率较高;复合纳米粒子比普通CdS降解效率高,2 min时高出50%,400 min时高出21.3%.初步提出了复合纳米粒子光催化降解机理,复合纳米粒子的吸附作用是光催化降解作用的前置步骤.     

Ag-ZnO/生物质炭纳米复合材料的制备及协同可见光催化性能

以醋酸锌(Zn(CH₃COO)₂·2H₂O)为锌源、硝酸银(AgNO₃)为掺杂源、纤维素纳米晶体(Cellulose nanocrystal, CNC)为生物模板，通过溶胶-凝胶法结合碳化处理，制备了Ag-ZnO/生物质炭(Biochar)复合材料。采用TEM、XRD、BET、UV-Vis DRS对所制得的Ag-ZnO/Biochar复合材料进行表征。以亚甲基蓝(MB)为模型污染物，评价Ag-ZnO/Biochar复合材料在可见光源照射下的光催化性能，进一步阐明其光催化机制。结果表明:碳化后纳米ZnO仍保持良好的分散性，球形Ag纳米粒子均匀分散在ZnO表面，形成Ag-ZnO/Biochar三元复合材料。与Ag-ZnO和ZnO/Biochar复合材料相比，Ag-ZnO/Biochar复合材料在可见光下的光催化降解率显著提高。这是由于生物质炭赋予复合体系良好的吸附性能，使MB的光催化降解反应持续发生；而Ag纳米粒子的表面等离子体共振(Surface plasmon resonance, SRP)效应则增强了复合体系在可见光区的吸收。其中，当AgNO₃、CNC、Zn(CH₃COO)₂·2H₂O的质量比为0.01:0.25:1时，制得的Ag-ZnO/Biochar复合材料在可见光下具有最佳的光吸收性能和MB降解效率:室温条件下，黑暗中吸附30 min，再用可见光照射120 min，即可达到99%的MB降解率，显著高于Ag-ZnO(约23%)和ZnO/Biochar复合材料(约64%)。      

硫化镉/石墨烯复合光催化剂的微波水热合成及DFT研究

采用微波水热法制备了CdS/rGO纳米复合光催化剂,通过XRD、FTIR、XPS、SEM、TEM对其结构和形貌进行了表征,结合UV-Vis和密度泛函(DFT)计算对异质界面的电荷转移机制进行了研究。结果表明所得复合材料中CdS分散性好、显示出较高的可见光催化活性和光稳定性。当rGO含量为0.5 mg/mL时复合材料的光催化性能最佳,可见光照射120 min后亚甲基蓝(MB)的光降解率达到94.40%,且五次循环实验光催化效果接近。界面相互作用、差分电荷密度、平均静电势等计算结果表明CdS与rGO通过范德华弱相互作用形成稳定异质界面,电荷由CdS向rGO转移,电子和空穴在两相界面实现了有效分离,因而材料的光催化性能得到增强。     

Preparation of novel CdS-graphene/TiO2 composites with high photocatalytic activity for methylene blue dye under visible light

In this study, CdS combined graphene/TiO₂ (CdS-graphene/TiO₂) composites were prepared by a sol–gel method to improve on the photocatalytic performance of TiO₂. These composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and transmission electron microscopy (TEM). The photocatalytic activities were examined by the degradation of methylene blue (MB) under visible light irradiation. The photodegradation rate of MB under visible light irradiation reached 90·1% during 150 min. The kinetics of MB degradation were plotted alongside the values calculated from the Langmuir–Hinshelwood equation. 0·1 CGT sample showed the best photocatalytic activity, which was attributed to a cooperative reaction between the increase of photo-absorption effect by graphene and photocatalytic effect by CdS.     

ZnS/还原氧化石墨烯复合材料的制备及光催化性能

水热法一步合成ZnS/还原氧化石墨烯（ZnS/RGO）复合材料,通过XRD、FTIR、Raman、SEM分析溶剂（乙醇、水）对ZnS/RGO复合材料形貌和结构的影响。结果表明,以乙醇为溶剂制备的ZnS颗粒尺寸小、均匀分散在石墨烯片层上,在形成ZnS纳米颗粒的同时将氧化石墨烯（GO）还原成石墨烯。对亚甲基蓝（MB）的光催化结果显示,ZnS/RGO复合材料具有优异的光催化性能,其光催化速率是纯ZnS颗粒的3.7倍,石墨烯作为优良光生电子的传输通道和收集体能够降低光生电子-空穴对的重新结合率,极大提高了ZnS/RGO复合材料的光催化性能。      

ZnS纳米粒子修饰FeWO4纳米棒增强可见光催化活性研究

采用两步水热辅助微乳液法,制备出硫化锌纳米粒子修饰钨酸亚铁纳米棒异质结光催化剂。TEM,EDS测试表明硫化锌纳米粒子均匀的负载在钨酸亚铁纳米棒表面。通过调节钨酸亚铁的加入量制备出了不同质量比的异质结光催化剂样品,与单独的硫化锌粒子和钨酸亚铁纳米棒相比,异质结构ZnS/FeWO4光催化剂对亚甲基蓝染料展现出高效的降解性能,其中0.2-ZnS/FeWO4样品4 h的降解率达到93%。异质结催化剂光催化性能的提高可以归因于异质结构的存在降低了光生电子和空穴的复合速率,加速了光生电子的转移,从而提高了量子效率。     

CsTi2NbO7@N-TiO2杂化核壳结构的制备及其可见光催化性能

将CsTi₂NbO₇与异丙醇钛混合后与尿素在空气中煅烧制备出CsTi₂NbO₇@N-TiO₂核壳杂化材料,用XRD、SEM、TEM、UV-Vis DRS和XPS等手段对样品进行了表征。结果表明,N掺杂使TiO₂带隙变窄和吸收边红移,实现了可见光响应。杂化、核壳结构和N掺杂的协同作用不仅使CsTi₂NbO₇@N-TiO₂杂化核壳结构材料具有较强的可见光吸收特性,异质结面的存在还导致光生载流子分离和迁移效率增强,从而提高了可见光降解亚甲基蓝(MB)的光催化活性,其反应速率常数约为CsTi₂NbO₇的5.8倍。同时,这种材料还具有良好的光催化循环稳定性。     

Preparation, characterization and photocatalytic properties of CdS nanoparticles dotted on the surface of carbon nanotubes

Cadmium sulfide (CdS) nanoparticles dotted on the surface of multiwalled carbon nanotubes (MWCNTs) have been synthesized by the polyol method. The as-prepared materials were characterized by x-ray powder diffraction, transmission electron microscopy, scanning electron microscopy, and Brunauer-Emmett-Teller adsorption analysis. The results indicate that CdS nanoparticles with diameter of 5-8?nm are thickly and uniformly coated on the surface of the MWCNTs. The photodegradation of azo dye using these materials was evaluated by the degradation of Brilliant Red X-3B under visible light. The coated nanotubes show higher photocatalytic activity than both CdS alone and a CdS/activated carbon sample; in addition, there is an optimum content of MWCNTs. The presence of MWCNTs can also hamper the photocorrosion of CdS. The mechanism for the enhancement of MWCNTs on the adsorption and photocatalytic property of CdS is investigated for the first time.     

Enhanced photocatalytic performance of Cu2O nano-photocatalyst powder modified by ball milling and ZnO

In this paper, a ball milled Cu₂O-ZnO nano-photocatalyst with good photocatalytic performance in visible light range was prepared. Effect of ZnO presence and ball milling of Cu₂O on the structure, microstructure, optical properties and photocatalytic performance were studied. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), high resolution transmission electron microscopy (HRTEM), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) analysis and UV–Vis spectrophotometer were used as characterization techniques. FESEM results indicated that ball milling of Cu₂O changed the morphology of Cu₂O-ZnO composite. The uniform formation of ZnO particles with average size of 30 nm over the Cu₂O surface was observed. The formation of p-n heterostructure with good contact between Cu₂O and ZnO nanoparticles was found by HRTEM image. Ball milling of Cu₂O promotes visible light absorption and reduction band gap to 1.9 eV in Cu₂O-ZnO photocatalyst. Intensity of PL spectra for the ball milled Cu₂O-ZnO photocatalyst was obviously lower. Ball milled Cu₂O-ZnO photocatalyst shows the highest photocatalytic activity and degradation efficiency of 98% was obtained for 2 mg/L methylene blue (MB) solution after 240 min. The kinetics of the photodegradation was followed the Langmuir-Hinshelwood (L-H) model and degradation rates were decreased by increase of MB concentration. In the case of ball milled Cu₂O and presence of ZnO, the MB degradation kinetics was two times faster.     

Enhancement of the photoelectrochemical response of poly(terthiophenes) by CdS(ZnS) core-shell nanoparticles

We have investigated the photoelectrochemical properties of hybrid films of polythiophenes poly(4,4″dimethoxy-3′-methyl-2,2′:5′,2″ terthiophene) (PDM), poly(4,4″dipentoxy-3′-methyl-2,2′:5′,2″ terthiophene) (PDP), and cadmium sulfide/zinc sulfide (CdS(ZnS)) core-shell nanoparticles. Although CdS(ZnS) nanoparticles present enhanced exciton trapping, light harvesting by hybrid films was enhanced when compared to those of pure PDM and PDP films. This enhancement is explained in terms of electron and hole transfer mechanisms at different excitation wavelengths. The more efficient light harvesting of PDM/CdS(ZnS) when compared to that of PDP/CdS(ZnS) was attributed to its broader absorption spectrum and more efficient electron hopping.     

TiO<Subscript>2</Subscript>/graphene composite from thermal reaction of graphene oxide and its photocatalytic activity in visible light

In this study, the P25 TiO₂ nanoparticles and graphene sheets (GSs) composite were prepared from a facile thermal reaction of graphene oxide. Its microstructures and photocatalytic properties were characterized and measured using X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), Brunauer–Emmett–Teller (BET) specific area analysis, X-ray photoelectron spectroscopy (XPS), FT-IR spectra, and ultraviolet–visible (UV–vis) diffuse reflectance spectroscopy. Compared with pure P25 nanoparticles, the results reveal that (1) there is a red shift about 20 nm in the absorption edge of the P25/graphene composite; (2) the photocurrent of the composite is about 15 times higher than that of pure P25; (3) the visible light photocatalytic activity of the composite is enhanced greatly on decomposition of methylene blue (MB). The photocatalytic mechanism of the P25/graphene composite is also discussed.     

复合材料CdS/Al-HMS的制备及可见光催化降解污染物制氢活性研究

采用模板法、离子交换法、沉淀法和浸渍法等多步反应合成了系列CdS/Al-HMS和负载的Pt/CdS/Al-HMS光催化复合材料; 利用XRD、TEM、XRF及UV-Vis漫反射光谱等分析技术对其进行了表征; 研究结果表明: CdS的复合量是影响CdS/Al-HMS复合材料结构的主要因素.当CdS复合量较低时,形成掺杂复合材料; 当CdS复合量较高时,形成纳米复合材料. 载6%Pt后的CdS/Al-HMS光催化复合材料降解甲酸的最高产氢速率为22.3mL/h, 420nm处的表观量子产率为12%.