The Antibacterial Activities of Copper Oxide Nanoparticles Synthesized Using Laser Ablation in Different Surfactants against Streptococcus mutans

Copper oxide nanoparticles(CuO NPs)were synthesised with laser ablation of a copper sheet immersed in deionized water(DW),cetrimonium bromide(CTAB),and sodium dodecyl sulphate(SDS),respectively.The target was irradiated with a pulsed Nd:YAG laser at 1064 nm,600 mJ,a pulse duration of 10 ns,and a repetition rate of 5 Hz.The CuO NPs colloidal were analyzed using UV–Vis spectroscopy,the Fourier transform infrared(FTIR)spectrometer,zeta potential(ZP),X-ray diffraction(XRD),transmission electron microscope(TEM)and field emission scanning electron microscopy(FESEM).The absorption spectra of CuO NPs colloidal showed peaks at 214,215 and 220 nm and low-intensity peaks at 645,650 and 680 nm for SDS,CTAB and DW,respectively.CuO NPs’colloidal results are(−21.6,1.2,and 80 mV)for negatively,neutrally,and positively charged SDS,DW,and CTAB,respectively.The XRD pattern of the NPs revealed the presence of CuO phase planes(110)(111),(20-2)and(11-1).The TEM images revealed nearly spherical NPs,with sizes ranging from 10–90,10–50,and 10–210 nm for CuO NPs mixed with DW,SDS and CTAB,respectively.FESEM images of all the synthesized samples illustrate the formation of spherical nanostructure and large particles are observable.The CuO NPs were tested for antibacterial activity against Streptococcus mutans by using the well diffusion method.In this method,CuO NPs prepared in DW at a concentration of 200μg/mL showed a greater inhibition zone against Streptococcus mutans.

Experimental Investigation of Upgraded Diesel Fuel with Copper Oxide Nanoparticles on Performance and Emissions Characteristics of Diesel Engine

The enhancement of the physicochemical characteristics of fossil fuel has been the subject of extensive research to achieve better efficiency and reduced emissions. Diesel is one of the fossil fuels that are highly consumed in daily life. This paper focuses on the behavior of a refined diesel fuel when copper oxide nanoparticles are added. The resulting blend ofnano-diesel has been analyzed using a four-stroke engine under two loads indicating light vehicles and heavy duty vehicles. The nano-diesel was prepared by the aid of an ultrasonicator and a mechanical homogenizer. A base diesel was taken as a reference to distinguish the effect of the nanoparticles additives. Three different samples with different concentrations are utilized in this study. As a result, the fuel consumption, exhaust temperature, brake power, power losses and engine efficiency have been evaluated and compared to the base diesel in order to demonstrate and access the enhanced performance of the nano-fuel blend. The three concentrations conducted were 100 ppm, 200 ppm and 300 ppm of copper oxide nanoparticles. The results represented that the pure refinery diesel has low exhaust temperatures, high brake power and high efficiency as compared to the commercial diesel supplied from a gas station. In addition, 300 ppm copper oxide nano-diesel showed improvement in engine performances as compared to the other concentrations and pure diesel. In this context, lowest fuel consumption for both passenger cars and heavy duty vehicles was achieved, brake power for passenger cars only was improved and input power showed improvement however, exhaust temperature was the highest as for this fuel.

Cu,N codoped carbon nanosheets encapsulating ultrasmall Cu nanoparticles for enhancing selective 1,2-propanediol oxidation

In the selective oxidation of biomass-based 1,2-propanediol(PDO)with oxygen as the terminal oxidant,it is challenging to improve the lactic acid(LA)selectivity for nonnoble metal nanoparticles(NPs)due to their limited oxygen reduction rate and easy C-C cleavage.Given the high economic feasibility of nonnoble metals,i.e.,Cu,in this work,copper and nitrogen codoped porous carbon nanosheets encapsulating ultrafine Cu nanoparticles(Cu@Cu-N-C)were developed to realize highly selective of PDO oxidation to LA.The carbon-encapsulated ultrasmall Cu^(0)NPs in Cu@Cu-N-C have high PDO dehydrogenation activity while N-coordinated Cu(Cu-N)sites are responsible for the high oxygen reduction efficacy.Therefore,the performance of catalytic PDO conversion to LA is optimized by a proposed pathway of PDO→hydroxylacetone→lactaldehyde→LA.Specifically,the enhanced LA selectivity is 88.5%,and the PDO conversion is up to 75.1%in an O_(2)-pressurized reaction system(1.0 MPa O_(2)),superior to other Cu-based catalysts,while in a milder nonpressurized system(O_(2)flow rate of 100 mL min-1),a remarkable LA selectivity(94.2%)is obtained with 39.8%PDO conversion,2.2 times higher than that of supported Au nanoparticles(1%Au/C).Moreover,carbon encapsulation offers Cu@Cu-N-C with strong leaching resistance for better recycling.

Synthesis and size control of copper nanoparticles and their catalytic application

The synthesis and catalytic properties of copper nanoparticles（Cunps） were reported using L-ascorbic acid as reducing and capping agent in aqueous medium. The effect of different concentrations of L-ascorbic acid on the particle size of Cunps was investigated. The synthesized Cunps were characterized by UV-Visible spectrophotometer, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and Fourier transform infrared（FTIR） spectrophotometer. The result indicates that the size of copper nanoparticles decreases with the increase in concentration of L-ascorbic acid. L-Ascorbic acid plays an important role to protect the copper nanoparticles from oxidation and agglomeration which helps nanoparticles to get better stability for the application. The synthesized Cunps show excellent catalytic activity in the oxidation of serine（Ser） by peroxomonosulphate（PMS）. The catalytic activity of Cunps increases with the decrease in size of Cunps. The Cunps are expected to be suitable alternative and play an imperative role in the fields of catalysis and environmental remediation.

Influence of nano-Al_2O_3-reinforced oxide-dispersion-strengthened Cu on the mechanical and tribological properties of Cu-based composites

The mechanical and tribological properties of Cu-based powder metallurgy （P/M） friction composites containing 10wt%-50wt% oxide-dispersion-strengthened （ODS） Cu reinforced with nano-Al2O3 were investigated. Additionally, the friction and wear behaviors as well as the wear mechanism of the Cu-based composites were characterized by scanning electron microscopy （SEM） in conjunction with energy-dispersive X-ray spectroscopy （EDS） elemental mapping. The results indicated that the Cu-based friction composite containing 30wt% ODS Cu exhibited the highest hardness and shear strength. The average and instantaneous friction coefficient curves of this sample, when operated in a high-speed train at a speed of 300 km/h, were similar to those of a commercial disc brake pad produced by Knorr-Bremse AG （Germany）. Additionally, the lowest linear wear loss of the obtained samples was （0.008 ± 0.001） mm per time per face, which is much lower than that of the Knorr-Bremse pad （（0.01 ± 0.001） mm）. The excellent performance of the developed pad is a consequence of the formation of a dense oxide composite layer and its close combination with the pad body.

Formation of copper oxide nanowires and nanoparticles via electrospinning

Copper oxide nanowires and nanoparticles were fabricated through electrospinning followed by calcinations in different heating conditions.It was found that the solution viscosity and environment humidity had great impact on the morphologies of precursor nanowires,and the parameters of heat treatment,including final temperature and heating rate,significantly affected the product morphologies.

Synthesis and characterization of lanthanum-doped curcumin-functionalized antimicrobial copper oxide nanoparticles

Flavonoid-based nanomaterials have extensive potential in antimicrobial research because of their non-toxicity,large-scale producibility,and chemical stability.An efficient combination of flavonoids and rare earth metals can have excellent antimicrobial properties owing to their robust medicinal and physicochemical properties.In this study,we synthesized copper oxide(CuO)nanoparticles(NPs)using a reflux reaction and repeated doping with the rare earth element lanthanum to prepare La-CuO NPs.Next,these La-CuO NPs were functionalized with the flavonoid curcumin,and the modified NPs were termed Cu-La-CuO NPs.These NPs were chemically characterized via microscopic and spectroscopic techniques,including transmission electron microscopy(TEM),scanning electron microscopy(SEM),ultraviolet-visible(UV-Vis)adsorption,Fourier transform infrared spectroscopy(FT-IR)spectroscopy,and powder X-ray diffraction(XRD)analysis.The SEM-EDX analysis reveals the elements doped into the native CuO NPs.The TEM and XRD characterization results show,in detail,the distinct morphology and phase composition of the prepared CuO,La-CuO,and Cu-La-CuO NPs.The antimicrobial activity of the Cu-La-CuO NPs was investigated on bacteria,such as Escherichia coli(E.coli)and Bacillus subtilis(B.subtilis),and fungi,including Aspergillus niger(A niger).The Cu-La-CuO NPs delivers excellent antimicrobial effects due to the incorporation of lanthanum and curcumin into the CuO NPs.The Cu-La-CuO NPs show excellent antimicrobial potentials with an adequate zone of inhibition values around 2.2 and 2.9 mm in E.coli and A.niger,respectively.Live and dead analysis studies suggest the antimicrobial effects of lanthanum and curcumin moieties over native CuO NPs.The obtained results are significant in developing of rare earth metal-based flavo no id-conjugated nanocomposites against typical microbes.

Copper nanoparticles/polyaniline-derived mesoporous carbon electrocatalysts for hydrazine oxidation

Copper nanoparticles-decorated polyaniline- derived mesoporous carbon that can serve as noble metal-free electrocatalyst for the hydrazine oxidation reaction （HzOR） is synthesized via a facile synthetic route. The material exhibits excellent electrocatalytic activity toward HzOR with low overpotential and high current density. The material also remains stable during the electrocatalytic reaction for long time. Its good electro- catalytic performance makes this material a promising alternative to conventional noble metal-based catalysts （e.g., Pt） that are commonly used in HzOR-based fuel cells.

Homogeneous and Heterogeneous Performances of Pyridinium Ionic Liquids in the Allylic Oxidation of Ionone-like Dienes

The combination of relatively low-cost ionic liquids, simple copper salt, and terminal oxidant tert-butyl hydroperoxide provided an efficient and environmentally friendly approach to the preparation of ionone-like dienones. Six pyridinium ionic liquids were evaluated in allylic oxidation of α-ionone and β-ionone. The 60%-70% yields of 3-oxo-α-ionone were obtained with 0.02 0.20 mmol of CuCl2·2H2O as catalyst, 3-5 mmol of tert-butyl hydroperoxide as oxidant and 1 g of [Bpy]PF6 as solvent for 4-20 h at 60℃. The facile recovery and recycle of catalyst were also achieved. More significantly, peculiar phase behaviors of [Bpy]PF6 and [Epy]PF6 offered the catalytic system advantages of homogeneous reaction and heterogeneous separation. Scanning electron microscope （SEM） images of [Bpy]PF6 provided evidences for the behaviors. Transmission electron microscope （TEM） micrographs showed copper salt nanoparticles catalyst formed and stabilized in pyridinium ionic liquids.

铜纳米粒子在有机合成中的应用

随着纳米技术的飞速发展,铜纳米粒子因其独特的物理化学性质,如高活性、大比表面积和良好的选择性,在有机合成中展现了广泛的应用前景。讨论了新型铜纳米材料在各种类型有机反应中的应用,包括多组分“一锅法”反应合成药物活性分子、炔-叠氮化合物环加成反应合成三唑和四唑衍生物、醇的选择性氧化反应、硝基的还原反应、C—X(C,N,O)偶联反应(其中C—C偶联包括Mizoroki-Heck、Suzuki-Miyaura、Glaser-Hay等偶联反应;C—N及C—O偶联包括Chan-Lam、Buchwald-Hartwig、Ullmann、Goldberg等偶联反应)。大多数铜纳米粒子催化反应具有反应操作简单、反应条件温和、催化效率高、官能团耐受性好、成本低、反应体系干净且铜催化剂可重复使用等优点。铜纳米粒子在有机合成中的应用将对有机合成方法学产生重要影响,并促进有机铜化学的进一步发展。

用于抑制肿瘤细胞生长的叶酸修饰聚多巴胺涂层的氧化铜纳米颗粒

采用沉淀转化法制备出粒径约为10 nm的氧化铜纳米颗粒(CuO NPs),通过盐酸多巴胺(DA HCl)在其表面进行聚合,并通过叶酸(FA)修饰形成CuO@PDA-FA NPs。采用透射电子显微镜、红外光谱仪、纳米粒径电势分析仪、X射线光电子能谱对纳米颗粒的形貌和性质进行表征。结果表明,制备的CuO@PDA-FA NPs粒径约为190 nm。材料降解亚甲基蓝试验和氧化葡萄糖试验证实CuO@PDA-FA NPs具备类过氧化物酶(POD)活性和类葡萄糖氧化酶(GOD)活性。近红外光热转换试验证实CuO@PDA-FA NPs具有良好的光热效应和光热稳定性。体外细胞毒性试验、细胞摄取试验和活性氧生成试验结果表明,CuO@PDA-FA NPs能主动靶向肿瘤细胞,并通过光热治疗(PTT)/化学动力学治疗(CDT)/饥饿治疗(ST)协同效果杀伤肿瘤细胞。

TiO_(2) nanofiber-supported copper nanoparticle catalysts for highly efficient methane conversion to C1 oxygenates under mild conditions

The selective oxidation of methane under mild conditions remains the“Holy Grail of Catalysis”.The key to activating methane and inhibiting over-oxidation of target oxygenates lies in designing active centers.Copper nanoparticles were loaded onto TiO_(2) nanofibers using the photo-deposition method.The resulting catalysts were found to effectively convert methane into C1 oxygenated products under mild conditions.Compared with previously reported catalysts,it delivers a superior performance of up to 2510.7 mmol·g_(Cu)^(-1)·h^(-1) productivity with a selectivity of around 100%at 80℃for 5 min.Microstructure characterizations and density functional theory(DFT)calculations indicate that TiO_(2) in the mixed phase of anatase and rutile significantly increases the Cu^(+)/CuO ratio of the supported Cu species,and this ratio is linearly related to the formation rate of oxygen-containing species.The CuI site promotes the generation of active O species from H_(2)O_(2) dissociation on Cu_(2)O(111).These active O species reduce the energy barrier for breaking the C-H bond of CH_(4),thus boosting the catalytic activity.The methane conversion mechanism was proposed as a methyl radical pathway to form CH_(3)OH and CH_(3)OOH,and then the generated CH_(3)OH is further oxidized to HOCH_(2)OOH.

Uniform and Homogeneous Growth of Copper Nanoparticles on Electrophoretically Deposited Carbon Nanotubes Electrode for Nonenzymatic Glucose Sensor

The multiwalled carbon nanotubes thin-film-based electrode was fabricated by electrophoretic deposition and modified with copper （Cu） nanoparticles to fabricate Cu/CNTs nanocomposite sensor for nonenzymatic glucose detection. The expensive glassy carbon electrode was replaced by fluorine-doped tin oxide glass containing CNTs film to confine the Cu nanoparticles growth by electrodeposition through cyclic voltammetry （CV）. The ultraviolet visible and X-ray diffraction analysis revealed the successful deposition of Cu nanoparticles on the CNTs-modified electrode. The atomic force microscopy images confirrqed the morphology of electrodeposited Cu on CNTs film as uniformly dispersed particles. The electrocatalytic activity of electrode to the glucose oxidation was investigated in alkaline medium by CV and amperometric measurements. The fabricated sensor exhibited a fast response time of less than 5 s and the sensitivity of 314 μA rnM^-1 cm^-2 with linear concentration range （0.02-3.0 mM） having detection limit 10.0 μM. Due to simple preparation of sensor, Cu/CNTs nanocomposite electrodes are a suitable candidate for reliable determination of glucose with good stability.

The combined toxicity and mechanism of multi-walled carbon nanotubes and nano copper oxide toward freshwater algae:Tetradesmus obliquus

Nanoparticles(NPs)are widely used for their special physical properties and released into the natural environment.When two types of NPs exist in the same environment,the presence of one type of NP may affect the properties of the other type of NP.This study investigated the toxic effects of multi-walled carbon nanotubes(MWCNTs)and copper oxide nanoparticles(Cu O NPs)on Tetradesmus obliquus.Both NPs had toxic effects on algae,and the toxic effects of MWCNTs were significantly stronger than Cu O NPs which the 96-hr median effective concentration to algae were 33.8 and 169.2 mg/L,respectively.Oxidative stress and cell membrane damage were the main reasons for the toxicity of NPs to algae,and they were concentration-dependent,and the existence of Cu O NPs in some groups reduced cell membrane damage caused by MWCNTs which may because that Cu O NPs formed heteroaggregation with MWCNTs,reducing the contact of nanoparticles with cell membranes,then reducing physical damage.Scanning electron microscopy(SEM)and transmission electron microscope(TEM)results indicated cell damage,the heteroaggregation of MWCNTs-Cu O NPs and obvious nanoparticles internalization.In some groups,the presence of Cu O NPs significantly reduced reactive oxygen species(ROS)level induced by MWCNTs.However,for the highest concentration group,the ROS level was much higher than that of the two NPs alone treatment groups,which might be related to the high concentration of MWCNTs promoting the internalization of Cu O NPs.MWCNTs and Cu O NPs affected and interacted with each other,causing more complex toxic effects on aquatic organisms.

纳米氧化铜对白菜种子发芽的毒害作用研究

纳米材料的生态毒性问题越来越受到人们的广泛关注。本文探讨了纳米氧化铜（22～75nm，平均43nm）对白菜种子发芽的影响，并以微米氧化铜和铜离子（Cu^2＋）进行对比分析。结果表明，各浓度处理（0．2、0．5、1、2．4、8mg·L^-2）纳米氧化铜对白菜种子发芽率与对照相比均无显著差异（P〉0．05），但在较低浓度下（0．4mg·L^-1）对根伸长和芽伸长即表现出抑制作用。随着纳米氧化铜浓度增加，对根伸长抑制率显著提高，对芽伸长抑制率则缓慢提高，其半抑制浓度（IC50）分别为11．4mg·L^-1和1309．4mg·L^-1.100mg·L^-1时，微米氧化铜对白菜根、芽伸长的抑制率都小于20％，其毒性小于纳米氧化铜；但纳米氧化铜的毒性并非其溶解出的铜离子所致。

不同培养介质中纳米氧化铜对小麦毒性的影响

采用琼脂培养和水培方法比较了纳米氧化铜(CuONPs)在不同暴露介质中的环境化学行为及其对小麦根生长的影响,并探讨了不同培养介质对CuONPs植物毒性的影响机制.结果表明,琼脂介质相对水相(营养液)环境可以减少CuONPs的团聚,增强其分散性.在琼脂和水相中Cu离子溶出随CuONPs浓度变化规律存在明显差异,在50～1000mg CuONPs·L-(1以Cu计)范围内,CuONPs在琼脂中无论是Cu2+的溶出浓度还是溶出比率均低于其在水相中的值.CuONPs在不同介质中表现出显著的小麦毒性差异.琼脂培养下小麦根生长半抑制效应浓度EC50(以CuONPs浓度表示)为108mg·L-1,而在水培方式下为9.0mg·L-1,说明琼脂介质极大缓解了CuONPs引起的植物毒性.分析表明,Cu2+溶出浓度较CuONPs投放量与小麦根生长抑制效应之间存在更好的指数相关关系,这说明该研究体系下CuONPs小麦毒性主要是由纳米颗粒释放Cu2+引起的.此结论较好地解释了当培养介质从水相变成琼脂时,Cu2+溶出减少,纳米毒性降低的现象.该研究结果认为,当前国内外使用水培法获得的纳米材料植物毒性研究结果在外推至实际土壤状况时将高估其环境安全性风险,推荐使用琼脂作为纳米材料土壤环境风险评价的模拟介质.

碳包覆纳米铜粒子的制备及抗氧化性能

以碳粉和铜粉为原料,碳粉和铜粉的质量比分别为4：1、3：2、2：3、1：4时,采用碳弧法制备4种碳包覆纳米铜粒子;采用X射线衍射（XRD）、透射电子显微镜（TEM）、热重分析（TGA）和差示扫描量热法（DSC）对样品的物相结构组成、形貌、尺寸、相组成以及抗氧化性能进行研究;并对影响碳包覆纳米铜粒子粒径以及制备速率的因素进行研究。结果表明：碳包覆纳米铜粒子具有典型的核壳型结构,内核为面心立方的金属铜,外壳为石墨碳层;碳包覆铜纳米颗粒的粒径为20~60nm,粒径随着样品电极中的金属铜含量、放电电流、反应气压的增加而增大;随着样品电极中金属铜含量的增加以及放电电流的增大,碳包覆纳米铜粒子的制备速率加快,而反应气压对制备速率没有明显的影响;随着铜含量的增加,内部铜核具有进一步晶化的趋向,铜对外层碳层的石墨化具有催化作用,铜含量越高碳的石墨化程度越明显;外面的碳层能有效阻止内核的纳米铜粒子的氧化,碳包覆纳米铜粒子比纯铜粉末表现出更好的抗氧化性能。

基于铜纳米粒子/氧化锌/石墨烯修饰电极的电化学方法测定硫酸卡那霉素

在氧化锌/石墨烯(ZnO/GO)修饰ITO电极表面电沉积铜纳米粒子(CuNPs),制备了一种新型的电化学传感器,用于检测硫酸卡那霉素(KANA)。采用扫描电镜对制备的纳米材料以及修饰电极表面进行表征。优化后的测定条件为:在0.15 mol/L PBS缓冲溶液(pH 6.5)中,电沉积扫描圈数为40圈时, KANA在铜纳米粒子/氧化锌/石墨烯(CuNPs/ZnO/GO/ITO)电极上的电化学响应最大。KANA在电极表面的反应机理为单电子转移过程,修饰电极有效表面积为0.482 cm^2,是裸电极的2.42倍。在0.99～30.6μmol/L范围内,响应电流与KANA浓度呈良好的线性关系,线性方程为I_(pc)=-5.183c-4.544×10^(-6),R^2=0.9975,检出限为:0.31μmol/L,加标回收率为97.8%～103.6%。此传感器具有良好的稳定性与重现性,可用于药物中KANA的检测。

导电涂料中纳米铜粉抗氧化性的研究

为了提高纳米铜粉的抗氧化能力及其在聚合物基体中的分散性,在钠米铜粉表面包覆一层导电性和抗氧化性均佳的银.以水合肼为还原剂、PVP(聚乙稀吡咯烷酮)和硅烷偶联剂(KH-550)为分散剂,采用二月桂酸二丁基锡对纳米铜颗粒表面进行活化处理,然后采用置换反应法制备得到了与原纳米铜粉粒径和形貌大致相同的核壳型铜-银双金属粉末.采用X射线衍射(XRD)、XRF、TGA等手段分析了核壳铜-银双金属粉的抗氧化性能,并用透射电子显微镜(TEM)对粉末形貌进行表征.结果表明,经表面活化处理后得到的核壳铜-银双金属粉,在镀银质量分数较低(37.68%)时也能形成完全包覆型结构.包覆后的铜纳米颗粒在700℃以下没有任何氧化现象.

环境水体中纳米氧化铜对金鱼藻的毒性效应研究

采用模拟水体环境的方法,研究了低浓度（2~8 mg.L-1）纳米氧化铜（CuONPs）溶液对金鱼藻生长的毒性影响,并与相同浓度的微米氧化铜和可比剂量铜离子进行对比分析。实验结果显示在纳米氧化铜溶液的作用下,金鱼藻对Cu元素的积累量为相同浓度的微米氧化铜溶液作用下的6~12倍,金鱼藻体内的酶活性对纳米氧化铜溶液作用的浓度和时间均有明显反应。在作用20 d时,4mg.L-1的纳米氧化铜溶液作用下金鱼藻体内POD、SOD活性均达到最大值;在作用30 d时,同样浓度作用下金鱼藻的叶绿素含量达到峰值,其后逐步下降。对于8 mg.L-1纳米氧化铜溶液的可比剂量铜离子（0.23 mg.L-1）作用于金鱼藻,其POD活性、SOD活性和叶绿素含量的变化明显小于8 mg.L-1浓度的纳米氧化铜溶液。上述结果表明低浓度（4~8 mg.L-1）的纳米氧化铜溶液对金鱼藻生长有明显的抑制效应和毒害作用,纳米氧化铜对金鱼藻的生长表现出很强的纳米效应,其生长同时受到纳米氧化铜溶液作用时间的影响,但低浓度的微米氧化铜溶液对金鱼藻生长几乎不存在毒害作用。