Metal Nanoparticles on Stainless Steel Surfaces as Novel Heterogeneous Catalysts

The goal of this work was the development of a novel type of heterogeneous catalyst, consisting of bare metal nanoparticles on stainless steel foils, which can be shaped to any kind of architecture and, if necessary, heated electrically. Solutions of pre-prepared, ligand protected and monodispersed gold, palladium, platinum and rhodium nanoparticles were sprayed onto stainless steel foils, followed by the careful removal of the ligand molecules by an oxygen plasma treatment. Due to this, bare particles become irreversibly fixed on the steel support. It could be shown that the original particle sizes do not change during the plasma treatment. Foils, densely coated with the nanoparticles, were used for gas phase catalyses in a self-made reactor at room temperature or at 60 °C. Hydrogenation of 1,3-butadiene at 15 nm Pd and 2 nm Pt, CO oxidation at 16 nm, 8 nm and 1.4 nm gold and NO reduction with NH₃ at 2 nm Rh particles were performed, indicating that the novel catalysts might in principle be applicable in technical processes if the experimental conditions like form and temperature would be optimized. Dedicated to Professor Dieter Fenske on the occassion of his 65th birthday.     

Green synthesis of 1,2,3‐triazoles via Cu2O NPs on hydrogen trititanate nanotubes promoted 1,3‐dipolar cycloadditions

Cu₂O nanoparticles supported on hydrogen trititanate nanotubes (Cu₂O/HTNT) catalysts have been efficiently catalyzed the multicomponent synthesis of 1,2,3‐triazoles in water at room temperature from different azide precursors, for example organic halides, sulfonates and anilines. The catalysts were synthesized by hydrothermal & wet‐impregnation methods and was characterized by HR‐TEM, EDS, XRD, XPS, N₂‐adsorption desorption and ICP‐MS analysis. The catalyst could be recycled by centrifugation and reused up to seven cycles. The 1‐benzyl‐4‐(4‐chlorophenyl)‐1H‐1,2,3‐triazole ( 25 ) structure was proven by single crystal X‐ray diffraction studies.     

“On-water” synthesis of 3-substituted indoles via Knoevenagel/Michael addition sequence catalyzed by Cu doped ZnS NPs

Cu doped ZnS NPs represent a green catalyst for an ‘on-water’ one-pot rapid synthesis of 3-substituted indole derivatives via Knoevenagel/Michael addition reaction of indane-1,3-dione, aromatic aldehydes, and indole. The catalytic activity of Cu doped ZnS NPs was about sevenfold higher as compared to the ZnS NPs. The Cu doped ZnS NPs catalyst could be recovered and reused for five reaction cycles, giving a total TOF = 201 h⁻¹.     

Copper nanoclusters conjugated silica nanoparticles modified on carbon paste as an electrochemical sensor for the determination of dopamine

An electrochemical sensor based on modification of carbon paste electrode by glutathione‐capped copper nanoclusters silica nanoparticles (CuNCs/SiO₂NPs) composite for determination of dopamine in the presence of ascorbic acid was presented. Transmission electron microscopy, scanning electron microscopy, energy dispersive X‐Ray analysis, X‐ray photoelectron spectroscopy, Fourier‐transform infrared spectroscopy, X‐ray diffraction and electrochemical impedance spectroscopy were used for characterization of the developed electrode. The electrochemical behavior of dopamine on CuNCs/SiO₂NPs/carbon paste electrode was investigated by cyclic voltammetry and differential pulse voltammetry. Dopamine was determined in the range of 10.0 – 900.0 μM, and the limit of detection was obtained as 0.43 μM. The electrochemical behaviors of the coexisting electroactive species, which often cause interference with the determination of dopamine, were investigated. The results show that the developed electrode does not show any interference with respect to coexisting species, even in the presence of ascorbic acid. The developed electrochemical sensor was further employed for the determination of dopamine in human blood plasma, with a good recovery.     

Stainless steel cloth modified by carbon nanoparticles of Chinese ink as scalable and high-performance anode in microbial fuel cell

Microbial fuel cells(MFCs) have various potential applications.However,anode is a main bottleneck that limits electricity production performance of MFCs.Herein,we developed a novel anode based on a stainless steel cloth(SC) modified with carbon nanoparticles of Chinese ink(Cl) using polypyrrole(PPy)as a building block(PPy/Cl/SC).After modification,PPy/Cl/SC showed a 30% shorten in start-up time(36.4 ± 3.3 h vs.52.3± 1.8 h),33% increase in the maximum current(12.4 ± 1.4 mA vs.9.3± 0.95 mA),and2.3 times higher in the maximum power density of MFC(61.9 mW/m~2 vs.27.3 mW/m~2),compared to Ppy/SC.Experimental results revealed that carbon nanoparticles were able to cover SC uniformly,owing to excellent dispersibility of carbon nanoparticles in Cl.The attachment of carbon nanoparticles formed a fluffy layer on SC increased the electrochemically-active surface area by 1.9 times to 44.5 cm2.This enhanced electron transfer between the electrode and bacteria.Further,embedding carbon nanoparticles into the PPy layer significantly improved biocompatibility as well as changed functional group contents,which were bene ficial to bacteria adhesion on electrodes.Taking adva ntage of high mechanical strength and good conductivity,a large-size PPy/Cl/SC was successfully prepared(50×60 cm~2)demonstrating a promising potential in practical applications.This simple fabrication strategy offers a new idea of developing low cost and scalable electrode materials for high-performance energy harvesting in MFCs.     

Cu含量对Cu/Al-Ce-PILC上丙烯选择性催化还原NO反应的影响

 采用聚合羟基复合阳离子合成交联粘土Al-Ce-PILC,经SO2-4改性后,以浸渍法制备了用于C3H6选择性还原NO反应的铜基交联粘土催化剂Cu/Al-Ce-PILC. 用XRD,XPS和TPR等技术对催化剂进行了表征,并考察了Cu含量对催化剂性能的影响. 结果表明,Cu负载未改变Al-Ce-PILC的结构; w(Cu)=2%时,Cu物种以Cu+和Cu2+两种形式存在,催化剂具有最高的催化活性和较宽的操作温度范围,在反应气组成为0.22%NO-0.12%C3H6-2.0%O2-97.66%He,空速为 24000 h-1和温度为350 ℃的条件下,NO转化率可达56.4%,700 ℃下仍可达22.3%; w(Cu)=5%时,催化剂中有明显的CuO物相存在,该物相促进C3H6的深度氧化,从而降低了NO选择性还原反应的性能.     

Oxidative amidation of aromatic aldehydes with amine hydrochloride salts catalyzed by silica‐coated magnetic carbon nanotubes (MagCNTs@SiO2)‐immobilized imine–Cu(I)

Mesoporous silica‐coated magnetic carbon nanotubes were prepared; their surface functionalization, followed by reaction with CuI, were carried out to develop a Cu‐grafted functionalized mesoporous material. This system is able to catalyze oxidative amidation of aromatic aldehydes with amine hydrochloride salts, generating amide derivatives in moderate to good yields. Magnetic properties of this catalyst led to easy separation as well as providing significant recyclability. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis of multifunctional polymer containing Ni‐Pd NPs via thiol‐ene reaction for one‐pot cascade reactions

Recently, acid–base bifunctional catalysts have been considered due to their abilities, such as the simultaneous activation of electrophilic and nucleophilic species and their high importance in organic syntheses. However, the synthesis of acid–base catalysts is problematic due to the neutralization of acidic and basic groups. This work reports a facial approach to solve this problem via the synthesis of a novel bifunctional polymer using inexpensive materials and easy methods. In this way, at the first step, heterogeneous poly (styrene sulfonic acid‐n‐vinylimidazole) containing pentaerythritol tetra‐(3‐mercaptopropionate) (PETMP) and trimethylolpropane trimethacrylate (TMPTMA) cross‐linkers were synthesized in the pores of a mesoporous silica structure using click reaction as a novel bifunctional acid–base catalyst. After that, Ni‐Pd nanoparticles supported on poly (styrenesulfonic acid‐n‐vinylimidazole)/KIT‐6 as a novel trifunctional heterogeneous acid–base‐metal catalyst was prepared. The prepared catalysts were characterized by various techniques like FT‐IR, TGA, ICP‐AES, DRS‐UV, TEM, FE‐SEM, EDS‐Mapping, and XRD. The synthesized catalysts were efficiently used as bifunctional/trifunctional catalysts for one‐pot, deacetalization‐Knoevenagel condensation and one‐pot, three‐step and a sequential reaction containing deacetalization‐Knoevenagel condensation‐reduction reaction. It is important to note that the synthesized catalyst showing high chemo‐selectivity for the reduction of nitro group, alkenyl double bond and ester group in the presence of nitrile. Moreover, it was found that the different nanoparticles including Ni, Pd, and alloyed Ni‐Pd showing different chemo‐selectivity and catalytic activity in the reaction.     

Linker‐free Gold Nanoparticle Superstructure Coated with Poly(dopamine) by Site‐Specific Polymerization for Amplifying Photothermal Cancer Therapy

Although linker‐free Au nanoparticle superstructures (AuNPSTs) have demonstrated to have satisfactory photothermal conversion efficiency owing to their enhanced visible‐near‐infrared absorption caused by the interparticle coupling, they cannot be used directly for in vivo photothermal therapy (PTT) of cancer because of poor stability. To address this issue, we herein propose a polymer‐coating strategy, dressing AuNPST on a poly(dopamine) (PDA) coat, and successfully investigate the in vivo PTT effect of AuNPSTs. By employing Triton X‐100 as an emulsifier for the formation of AuNPSTs, dopamine was site‐specifically polymerized around each AuNPST by the interaction between ?OH of Triton X‐100 and ?NH₂ of dopamine. As‐fabricated AuNPST/PDA has a sphere‐like shape with an average diameter of ～106 nm and the PDA shell is about 10 nm PDA thick. The AuNPST/PDA shows enhanced durability to heat, acid, and alkali compared with bare AuNPST. Also, under 808 nm laser irradiation, AuNPST/PDA shows photothermal conversion efficiency of ～33%, higher than bare AuNPST (～23%). Significantly, AuNPST/PDA can be used as in‐vitro and in‐vivo PTT agent and shows excellent therapeutic efficacy for tumor ablation thanks to its enhanced stability and biocompatibility, indicative of its potential practicability in clinical PTT.     

经阳极氧化处理的不锈钢负载贵金属新型催化剂用于挥发性有机化合物的治理

 催化氧化是一种处理VOCs有效的节能和经济的方法。不锈钢在工业上有很多的应用。由于其具有耐腐蚀性，而且其表面经阳极氧化能形成一层氧化膜，从而可应用于很多场合。但是以其为载体制成催化剂以处理VOCs还未见报告。本文介绍一种新型的催化剂，该催化剂以不锈钢阳极氧化膜为载体负载贵金属以用于VOCs处理。尤其是在经过1000℃的焙烧以后，对甲苯的燃烧仍然有良好的活性。 实验中的催化剂载体为不锈钢片（1Cr18Ni9Ti,0.3mm）。在30wt%的硫酸溶液中经过阳极氧化处理（选择40min，电流密度为1.5 A/dm3的条件）。然后在H2 [PtCl6] 和 PdCl2溶液中, 通过浸渍法将贵金属浸渍于载体而制得。 实验在固定床上进行，以甲苯为反应物，表1为评价结果。由表1可见Pt0.01wt%-Pd0.02wt%负载于不锈钢阳极氧化膜以后的催化剂，对于甲苯有良好的燃烧活性，尤其是，经过1000℃焙烧的催化剂的活性要比500℃ 和800℃ 被烧的催化剂的活性更高。 通过SEM表征了Pt0.01wt%-Pd0.02wt%不锈钢催化剂。图1a中空白的不锈钢载体的表面相对光滑，经过阳极氧化以后表面呈现均匀分布的微米粒径（0.3微末）复合氧化膜，与金属基体的接合牢固，表面的粗糙度也明显增加（Fig1b），可以有效地作为有机废气治理催化剂的担体。从而表现出较高的VOCs氧化活性。温度焙烧对催化剂的活性有很明显的影响，在经过500℃焙烧以后，催化剂表面有较大的颗粒团聚。随着温度提高到800℃和1000℃，其表面颗粒更趋于均匀且近似呈现一种接近纳米粒径的复合氧化膜结构；在甲苯的催化燃烧上，更是表现出很好的效果。 通过实验结果表明由于该催化剂具有很高VOCs去除活性，良好的热稳定性；催化剂容易加工成蜂窝，热稳定性好，机械强度高，抗机械震动，易导热的特性，在处理VOCs方面有很好的应用前景。     

ICP–AES法测定铬镍不锈钢中锰、铬、镍、硅、磷、铜、钼的含量

建立电感耦合等离子体原子发射光谱(ICP–AES)法测定铬镍不锈钢中锰、铬、镍、硅、磷、铜、钼7种元素含量的方法。试样用盐酸与硝酸混合酸溶液溶解,采用溶解国家标准样品的方法制备校准曲线溶液,确定了元素最佳分析谱线。各元素的含量在其测试范围内与原子发射强度呈良好的线性关系,线性相关系数不小于0.999,7种元素的检出限在0.000 3%~0.003 0%之间。该方法应用于铬镍不锈钢标准样品的测定,测定值与认定值相符,测定值的相对标准偏差在0.12%~1.15%之间(n=8)。应用于铬镍不锈钢样品测定时,加标回收率在90%~110%之间。该方法操作简便、迅速,可满足日常铬镍不锈钢中多元素含量的检测需要。     

Facile preparation of stainless steel microextraction fiber via in situ growth of metal–organic framework UiO‐66 and its application to sensitive analysis of polycyclic musks

A functional stainless steel microextraction fiber easily prepared by in situ growing metal–organic framework UiO‐66 was presented and used for high‐performance analysis of polycyclic musks. Via the robust Ag‐SH bonding reaction, mercaptoacetic acid was easily anchored on Ag film to provide carboxyl group on the stainless steel fiber, then in situ grown UiO‐66 was fulfilled via the coordination reaction between Zr⁴⁺ and carboxyl group. Good characteristics including large surface area, high thermal stability, and good adsorption property were achieved. Sensitive detection limits (0.015–0.040 ng/L) were achieved for polycyclic musks by coupling with gas chromatography with mass spectrometry, and it could be stable enough for 150 extraction cycles without a significant loss of extraction efficiency. Compared with the classical commercial fibers, 2.2–11.4 times higher enhancement factors were shown. Applied to the analysis of fortified river water samples, five typical polycyclic musks were well detected with the recoveries of 90.2–101.8%, respectively. It showed a facile approach for preparing stainless steel microextraction fiber via chemically bonding in situ grown metal–organic framework for high‐performance enrichment.     

A highly sensitive naphthalimide-based fluorescent probe for detection of Cu2+ via selective hydrolysis reaction and its application in practical samples

A novel fluorescent probe CN3, containing 1,8-naphthalimide and picolinate units, was synthesized, and its structure was characterized by ¹H nuclear magnetic resonance spectroscopy (H NMR), ¹³C nuclear magnetic resonance spectroscopy (C NMR), and mass spectroscopy techniques. The detection property of CN3 toward copper ions (Cu²⁺) has been investigated in ethanol–HEPES buffer (v/v = 1/1, pH = 7.40) solution by UV–Vis absorption and fluorescence emission spectra. The results showed that CN3 had a highly selective and sensitive fluorescence quenching response to Cu²⁺, which was attributed to the generation of weak fluorescent N-ethyl-4-hydroxyphenyl-1,8- naphthalimide (compound 2) in polar ethanol–HEPES buffer (v/v = 1/1, pH = 7.40) via selective hydrolysis reaction. The detection of CN3 for Cu²⁺ was not influenced in the presence of other competing metal ions, and the limit of detection was as low as 50.0 nM. Therefore, the color of CN3 changed from colorless to yellowish when the Cu²⁺ was added. Furthermore, the fluorescent probe CN3 was utilized to detect Cu²⁺ in real water samples with fine performance.     

电感耦合等离子体原子发射光谱同时测定不锈钢食用器皿铬、镍、镉溶出量

用4%醋酸溶液浸泡取自不锈钢食用器皿钢片样品,在室温条件下浸泡24h,将浸泡液按6:1浓缩.通过优化试验确定实验条件,用电感耦合等离子体发射光谱仪准确测定浸泡液中Cr、Ni、Cd的浓度.实验过程操作简单,多种元素同时测定节约试验时间.精密度试验和回收率试验说明该方法检测结果准确可靠.     

Iron oxide nanoparticles coated with green tea extract as a novel magnetite reductant and stabilizer sorbent for silver ions: Synthetic application of Fe3O4@green tea/Ag nanoparticles as magnetically separable and reusable nanocatalyst for reduction of 4‐nitrophenol

Green tea extract having many phenolic hydroxyl and carbonyl functional groups in its molecular framework can be used in the modification of Fe₃O₄ nanoparticles. Moreover, the feasibility of complexation of polyphenols with silver ions in aqueous solution can improve the surface properties and capacity of the Fe₃O₄@green tea extract nanoparticles (Fe₃O₄@GTE NPs) for sorption and reduction of silver ions. Therefore, the novel Fe₃O₄@GTE NPs nano‐sorbent has potential ability as both reducing and stabilizing agent for immobilization of silver nanoparticles to make a novel magnetic silver nanocatalyst (Fe₃O₄@GTE/Ag NPs). Inductively coupled plasma analysis, transmission and scanning electron microscopies, energy‐dispersive X‐ray and Fourier transform infrared spectroscopies, and vibrating sample magnetometry were used to characterize the catalyst. Fe₃O₄@GTE/Ag NPs shows high catalytic activity as a recyclable nanocatalyst for the reduction of 4‐nitrophenol at room temperature.     

反应条件对Cu/Al-Ce-PILC上丙烯选择性催化还原NO反应的影响

 采用聚合羟基复合阳离子合成交联黏土Al-Ce-PILC, 经SO2-4改性后,以浸渍法制备了铜基交联黏土催化剂Cu/Al-Ce-PILC, 并将其应用于C3H6选择性还原NO的反应,考察了预处理气氛、 O2和C3H6浓度、空速、水蒸气和SO2等反应条件对催化剂性能的影响. 结果表明, He预处理后催化剂表面的Cu物种以Cu+和Cu2+两种形式存在,而H2预处理后仅以Cu+存在, NO转化率最大值由23%升至56%. 反应体系中适当的O2和C3H6浓度可促进NO还原为N2, 但过高的浓度反而可降低NO的还原活性, O2同时可起到抑制积炭、清洁催化剂表面的作用. NO转化率随着空速的增大而降低. 10%水蒸气的存在可抑制NO的还原和C3H6的氧化,其转化率曲线向高温方向位移. 但是,由于金属氧化物交联柱表面的疏水特性, Cu/Al-Ce-PILC较Cu/ZSM-5具有较强的耐湿热稳定性, NO和C3H6最大转化率仅分别下降13%和5%. SO2的存在明显抑制了催化剂的低温活性,但对高温活性有一定促进作用.     

Achieving ultra-low friction of a-C:H film grown on 9Cr18Mo steel for industrial application via programmable high power pulse magnetron sputtering

Owing to the high hardness and hydrogen passivation of carbon bonds, hydrogenated diamond-like carbon (a-C:H) film has shown promising potential to achieve ultra-low friction and wear on steel surfaces. Here, a-C:H film was successfully deposited on 9Cr18Mo steel via programmable high power pulse magnetron sputtering and potential application for industrial was evaluated. The a-C:H films against different mating materials of GCr15 steel balls, Al₂O₃, Si₃N₄, ZrO₂, and a-C:H-coated GCr15 balls all showed ultra-low friction under a normal load of 5 N in a dry ambient air environment. Among them, self-mating tribo-system a-C:H films on steel surfaces and a-C:H-coated steel balls achieve best friction performance; the principal reason is that both contacting surfaces coated with a-C:H film have the lower electron affinities compared with other tribo-systems. However, the differences of coefficient of friction (COF) for uncoated-GCr15, Al₂O₃, ZrO₂, Si₃N₄, and a-C:H(GCr15) balls can be attributed to different sizes of clustering in wear debris. This work provides new insights on synthesis and industry application of the a-C:H films with ultra-low friction properties.     

Eco‐friendly magnetic clinoptilolite containing Cu(0) nanoparticles (CuNPs/MZN): as a new efficient catalyst for the synthesis of propargylamines via A3 and KA2 coupling reactions

In this reaserch a new and eco‐friendly magnetic catalyst for the synthesis of propargylamines is reported. Initial incorporation of Fe₃O₄ magnetic nanoparticles (MNPs) into the pores of the natural clinoptilolite zeolite followed by modification with epichlorohydrine and ethylenediamine and then immobilization of CuNPs on the surface of functionalized zeolite gave the desired catalyst (CuNPs/MZN). The CuNPs/MZN was fully characterized by various techniques such as FT‐IR, CHN, TGA, ICP, XRD, SEM, TEM and BET. A host of propargylamines were readily synthesized through using the catalyst in high yields and short reaction times via A³ and KA² coupling reactions of aldehydes/ketones, amines, and phenylacetylene. The CuNPs/MZN was easily separated from the reaction mixture by an external magnet and reused several times successfully. The catalyst has the potential for catalysis of various organic transformations.     

Gas-phase study on the C-C coupling of naphthol catalyzed by Cu IITMEDA: evidence for the key role of binuclear clusters

The mechanism of oxidative coupling of two naphthol molecules to form binaphthol catalyzed by Cu(OH)ClTMEDA (TMEDA=N,N,N',N'-tetramethylethylenediamine) was approached by means of a gas-phase model system. Concise evidence is provided that the coupling reaction proceeds in clusters with two Cu(II) centers, whereby the intermediacy of free naphthoxy radicals in the coupling step is avoided. In the absence of TMEDA, the cluster is bound via a bridging counterion and the coupling reaction is followed by cluster cleavage. The coordination of one or two TMEDA molecules to the reactive complex results in more efficient coupling of naphthol molecules, and moreover, the binuclear cluster is also conserved after the reaction is completed. The effect of TMEDA is twofold: First, it supports clustering of copper and, second, as a ligand bound to a copper center in the reactive complex, it weakens the bond between copper and the naphtholato ligand such that the naphtholato unit is more prone to undergo C--C coupling. Furthermore, a pronounced counterion effect is found that correlates well with condensed-phase data: weakly bridging counterions (e.g., NO3(-)) yield less stable dicopper clusters and the coupling reaction hardly occurs, whereas better bridging counterions (e.g., Cl(-) or Br(-)) provide more stable clusters that make the coupling reaction more efficient.     

Fluorescent sensing platform for low-cost detection of Cu2+ by coumarin derivative: DFT calculation and practical application in herbal and black tea samples

A fluorogenic probe based on a coumarin-derivative for Cu²⁺ sensing in CH₃CN/H₂O media (v/v, 95/5, 5.0 μM) was developed and applied in real samples. 3-(4-chlorophenyl)-6,7-dihydroxy-coumarin (MCPC) probe was obtained by synthetic methodologies and identified by spectral techniques. The probe MCPC showed remarkable changes with a “turn-off” fluorogenic sensing approach for the monitoring of Cu²⁺ at 456 nm under an excitation wavelength of 366 nm. The response time of the probe MCPC was founded as only 1 min. The detection limit of the probe MCPC was recorded to be 1.47 nM. The binding constant and possible stoichiometric ratio (1:1) values were determined by Benesi-Hildebrand and Job’s plot systems, respectively. The mechanism of the probe MCPC with Cu²⁺ was further confirmed by ESI-MS and FT-IR analyses, as well as supported by theoretical calculations. Furthermore, the probe MCPC was successfully employed for the practical applications to sense Cu²⁺ in different herbal and black tea samples. The proposed sensing method was also verified by ICP-OES method.