首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
《Electroanalysis》2018,30(9):2131-2144
Increasing demand of alternative energy sources leads to the development of new electrocatalytic materials for fuel cells. In present work, we report the synthesis of rGO/PEDOT : PSS (reduced graphene oxide/ Poly (3,4‐ethylenedioxythiophene) : Polystyrene sulfonate) nanocomposite by in‐situ polymerization method using EDOT as precursor and the nanocomposite is used as anode catalyst for methanol oxidation. Structural and chemical characterizations such as XRD, FTIR and Micro‐Raman confirm the formation of the nanocomposite. From TEM image, growth of nanofibrous PEDOT : PSS on rGO nanosheets is observed. Electrochemical characterizations of rGO/PEDOT : PSS/ITO electrode are performed by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and Chronoamperometry (CA) measurements. Methanol oxidation reactions are performed in 0.5 M NaOH solution. The anodic current of the nanocomposite coated ITO is found be 37.5 mA at 0.59 V due to methanol electro‐oxidation and retentivity of the electrode is 92 % of initial scan after 800 cycles. The chronoamperometric results reveal that the nanocomposite modified electrode exhibits better stability with retention factor of 42.4 % up to 3000 seconds. The rGO/PEDOT : PSS/ITO electrode exhibits enhanced electrocatalytic activity towards methanol oxidation reaction due to larger surface area and excellent conductivity of rGO nanosheet.  相似文献   

2.
In this work, a novel 1,4-bis (4- aminophenylethynyl)benzene (OPE-NH2, a symmetric linear conjugated oligo(phenylene ethynylene)s derive) and chemically-reduced graphene oxide (rGO) nanocomposite (OPE-NH2/rGO) was synthesized by a simple self-assembly method. The OPE-NH2/rGO nanocomposite was stable and water soluble. The formation of OPE-NH2/rGO nanocomposite was ascribed to the π–π stacking interaction between the conjugated structure of OPE-NH2 and rGO as well as the electrostatic force between the amino group of OPE-NH2 and the carboxyl group on rGO, which was characterized by FT-IR, UV–vis spectra and fluorescence spectra. The OPE-NH2/rGO nanocomposite exhibited significantly improved electrocatalytic activity to the oxidization of dopamine (DA) than that of rGO or OPE-NH2. The electrochemical performances of OPE-NH2/rGO were dependent on the OPE-NH2 contents, and OPE-NH2 content of 5 wt% exhibited the highest activity. Compared with that of rGO, the nanocomposite presented superior high sensitivity with detection limit of 5 nM, excellent selectivity, wide linear range (0.01–60 μM) and good stability on the determination of DA. The practical application of the developed OPE-NH2/rGO nanocomposite modified electrode was successfully demonstrated for DA determination in human serum samples.  相似文献   

3.
We report for the first time sinapic acid (SA) sensing based on nanocomposite comprising electrochemically tuned gold nanoparticles (EAuNPs) and solvothermally reduced graphene oxide (rGO). The synthesized EAuNPs, rGO, and EAuNPs‐rGO nanocomposite were characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), particle size analysis, and Raman spectroscopy. A proof‐of‐concept electrochemical sensor for SA was developed based on synthesized EAuNPs‐rGO nanocomposite, which was characterized by electrochemical techniques such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The developed sensor detected SA with a linear dynamic range (LDR) between 20 μM and 200 μM and detection limit (DL) of 33.43 (±0.21) nM (RSD<3.32 %). To show the useful purpose of the sensor probe in clinical applications, SA was detected in human urine samples, which showed the percentage recovery between 82.6 % and 92.8 %. Interferences due to various molecules such as L‐cystine, glycine, alanine, serum albumin, uric acid, citric acid, ascorbic acid, and urea were tested. Long‐term stability of the sensor probe was examined, which was found to be stable up to 6 weeks. The sensor fabricated using EAuNPs‐rGO nanocomposite has many attractive features such as; simplicity, rapidity, and label‐free detection; hence, it could be a method of choice for SA detection in various matrices.  相似文献   

4.
We have prepared nanocomposite films comprising of 3‐glycidoxypropyltrimethoxysilane (GOPS) and iron‐oxide (Fe3O4) onto indium‐tin‐oxide (ITO) glass plate for covalent immobilization of 21‐mer peptide nucleic acid (PNA). These films have been characterized using contact angle, atomic force microscopy (AFM), electrochemical techniques. The electrochemical response of the GOPS/ITO and Fe3O4‐GOPS/ITO electrodes has been investigated by hybridization with complementary, non‐complementary and one‐base mismatch using methylene blue as electrochemical indicator. The PNA/Fe3O4‐GOPS/ITO bioelectrode exhibits improved specificity and detection limit (0.1 fM) as compared to that of the PNA‐GOPS/ITO bioelectrode (0.1 pM). This PNA/Fe3O4‐GOPS/ITO electrode can be utilized for detection of hybridization with the complementary sequence in sonicated M. tuberculosis genomic DNA within 90 s of hybridization time.  相似文献   

5.
采用元素分析、红外光谱(FTIR)、X射线光电子能谱(XPS)、拉曼光谱、X射线衍射(XRD)、固体13C核磁共振波谱(13C MAS NMR)、热失重分析(TGA)、导电率测试以及原子力显微镜(AFM)等手段对正丁基氯化镁还原的氧化石墨烯进行了系统的表征. 结果表明, 正丁基氯化镁可以有效还原氧化石墨烯, 随着其用量的增加, 氧化石墨烯还原程度增加, 碳/氧摩尔比升高, 片层间距减小, 热稳定性增强, 导电率增大(可达3.6×102 S/m). 还原后部分氧化石墨烯片层发生聚集.  相似文献   

6.
In this article, we successfully fabricated the bionanocomposites using cellulose nanocrystals (CNCs) and reduced graphene oxide (rGO) reinforced into biodegradable polylactic acid (PLA) matrix through melt‐mixing method. Due to the affinity difference between hydrophilic CNC and hydrophobic PLA, the surface modification of CNC was employed using quaternary ammonium salts (CTAB) as a surfactant. The nanocomposites were developed using different blend ratios of CNC/modified CNC (1, 2, and 3) wt% and (0.5 wt%) rGO into the polymer matrix. The morphology of CNC, q‐CNC (modified CNC), and nanocomposites were inspected by atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). It is demonstrated from tensile tests that, the nanocomposite with 1 wt% CNC and rGO showed maximum tensile strength compared with PLA and its nanocomposites. Moreover, the nanocomposite with 1 wt% CNC and rGO was also having maximum thermal stability. From cytotoxicity evaluation, it is observed that all the nanocomposites are nontoxic and cytocompatible to HEK293 cells. In addition to this, the nanocomposite with q‐CNC showed enhanced barrier properties compared with PLA and PLA/CNC/rGO nanocomposite. The results obtained from different characterizations showed that the incorporation of surfactant onto CNC improved the dispersion in PLA but at the same time deteriorated the PLA matrix.  相似文献   

7.
Gold nanoparticle–polypyrrole nanocomposite film was electrochemically deposited in a single-step polymerization of pyrrole in the presence of 3-mercaptopropionic acid (MPA)-capped gold nanoparticles (GNPs) and p-toluenesulfonic acid (pTSA) on the surface of an indium tin oxide (ITO)-coated glass plate. The carboxyl functional groups surrounding the GNPs within the polymer matrix were utilized for the immobilization of urease enzyme through carbodiimide coupling reaction for the construction of a Urs/GNP(MPA)–PPy/ITO-glass bioelectrode for urea detection in Tris–HCl buffer. The resulting bioelectrode film was characterized by atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), contact angle measurement, Fourier transform infrared spectroscopy (FTIR), and electrochemical techniques. The potentiometric response of the bioelectrode made of polymer nanocomposite films of two different thicknesses prepared at 100 and 250 mC cm?2 charge densities, respectively, was studied towards the urea concentration in Tris–HCl buffer (pH 7.4). The thin polymer nanocomposite film-based bioelectrode prepared at 100 mC cm?2 charge density exhibited a comparatively good potentiometric response than a thick 250 mC cm?2 charge density film with a linear range of urea detection from 0.01 to 10 mM with a sensitivity of 29.7 mV per decade.  相似文献   

8.
Solvothermally synthesized cobalt sulphide/reduced graphene oxide (CoS/rGO) was used to fabricate an electrochemical sensor for detection of artemisinin. Microscopic techniques were used to characterize CoS/rGO nanocomposite. The electrochemical sensor was fabricated by modifying the surface of glassy carbon electrode with CoS/rGO nanocomposite. [Fe(CN)6]3−/4− was used as a mediator to aid oxidation of artemisinin. Differential pulse voltammetric technique was used for the detection of artemisinin. A linear range of 30–100 μM was used. Experimentally, a detection limit of 0.5 μM was obtained. Therefore, the developed sensor can be used for quality control of artemisinin.  相似文献   

9.

A simple ionic liquid-assisted approach for the fabrication of graphene-based nanocomposite is reported. Pd–CuO/rGO and Au–CuO/rGO nanocomposites are successfully fabricated with the assistance of the ionic liquid 1-butyl-3-methyl imidazolium tetrafluoroborate. The physicochemical features of nanocomposite are systematically characterized by XRD, FT-IR, Raman spectroscopy, XPS, TGA, FESEM, AFM, and HRTEM. Carbon monoxide has been used as a probe molecule to emphasize the performance of the fabricated materials. The results indicate that the incorporation of a little quantity of ionic liquid results in the creation of uniformly dispersed NPs simultaneously with the reduction of graphene oxide (GO) into rGO, which leads to a low-temperature CO oxidation process. Besides, the Au–CuO/rGO catalyst achieved excellent durability in CO oxidation for 14 h, without detectable deactivation. The low-temperature CO oxidation was mainly induced by the synergistic effects between the components of catalysts. The Au or Pd and CuO combination not only generates more interfaces, which is more favorable for the activation of oxygen but also enhances the catalyst reduction behavior. Consequently, a graphene composite catalyst can be considered a potential CO oxidation candidate.

  相似文献   

10.
《Electroanalysis》2017,29(2):602-608
Pt−Au nanoclusters decorated on the surface of reduced graphene oxide (rGO/Pt−Au) was facilely prepared by one‐pot electrochemical reduction. The morphology and composition of rGO/Pt−Au composites had been characterized by scanning electron microscopy (SEM) coupled with energy‐dispersive X‐ray spectrometry (EDX), fourier transform‐infrared spectroscopy (FT‐IR) and electrochemical methods. Ofloxacin is a member of synthetic quinolones which has been widely used for the treatment of common diseases in humans and animals. The performance of the rGO/Pt−Au nanocomposite toward the oxidation of ofloxacin was compared with the other similar nanostructures like rGO/Pt and rGO/Au. In the optimized conditions, two linear calibration curves were obtained, from 0.08 to 10 μM and 10 to 100 μM ofloxacin. A detection limit of 0.05 μM ofloxacin was observed at pH 5.7 for the GCE/rGO/Pt−Au. The proposed sensor was successfully applied to determine ofloxacin in tablets and human urine samples and the results were satisfactory.  相似文献   

11.
The electrochemical oxidation of reduced glutathione (GSH) catalyzed by electro generated Berlin green at carbon nanofibers-poly(diallyldimethylammonium chloride)/Prussian blue (CNFs-PDDA/PB) nanocomposite film modified ITO electrode has been studied. The CNFs-PDDA/PB nanocomposite film were fabricated by casting the composite CNFs enfolded PDDA on ITO electrode followed by electrochemical deposition of PB on the CNFs-PDDA matrix using cyclic voltammetry (CV). Electron microscopy (TEM, AFM), and Fourier transform infrared spectroscopy (FT-IR) studies were used to characterize the morphology and structure of the nanocomposite. The fabricated CNFs-PDDA/PB/ITO nanocomposite film electrode shows significant improvement of redox activity of PB due to the excellent electron transfer ability of CNFs. It was also found to possess prominent electrocatalytic activity toward the oxidation of glutathione with high sensitivity as high as 2.07 μA dm(3) mol(-1) cm(-2). A nontoxic, stable and convenient method for the detection of GSH in the concentration range of 6.0×10(-6) to 1.74×10(-5) M has been developed and it showed improved sensor performance compared to the unmodified PB electrode. The high sensitivity, wider linear range, good reproducibility, and the minimal surface fouling make this CNFs/PDDA/PB nanocomposite film a promising candidate for GSH sensors.  相似文献   

12.
黄火娣  张晓凤  张艺  乐丽娟  林深 《应用化学》2017,34(10):1209-1220
利用层层自组装(LBL)结合原位光照还原法,制备了一系列{还原氧化石墨烯/多金属氧酸盐}n多层复合膜({rGO/POMs}_n),并以此作为载体,再通过恒电势法将Pt纳米粒子电沉积到复合膜载体上,得到一种P t/{rGO/SiW_(12)}_n燃料电池阳极纳米复合膜催化剂。用紫外可见分光光度计(UV-Vis)、原子力显微镜(AFM)以及扫描电子显微镜(SEM)等技术手段对载体复合多层膜的生长情况以及负载Pt纳米簇的表面形貌进行表征。结果表明,载体多层膜{rGO/SiW_(12)}_6被连续均匀地组装到了不同基底(氧化铟锡,ITO或玻碳,GC)表面且多层膜表面平整,在选定恒电势下,沉积于其表面的Pt纳米粒子具有花簇状形貌且分布均匀。比较研究了分别引入3种不同的多金属氧酸盐(硅钨酸盐SiW_(12),磷钼酸盐PMo_(12),磷钨酸盐PW_(12))制得的多层复合膜催化剂,即Pt/{rGO/SiW_(12)}_6、Pt/{rGO/PMo_(12)}_6和Pt/{rGO/PW_(12)}_6。电化学实验研究表明,在甲醇酸性溶液中,Pt/{rGO/SiW_(12)}_6复合膜相较于Pt/{rGO/PMo_(12)}_6、Pt/{rGO/PW_(12)}_6和Pt作为催化剂对甲醇氧化具有更好的电催化活性、电化学稳定性以及更优异的抗CO毒化性能,是一种颇有应用前景的燃料电池阳极催化剂。  相似文献   

13.
FePt bimetallic nanoparticles were formed on reduced graphene oxide(rGO) with the help of double-stranded DNA(dsDNA) via a simple and universal route to obtain a FePt/DNA-rGO composite. The FePt nanoparticles with an average size of about 5 nm were well dispersed on rGO. FePt/DNA-rGO modified glassy carbon electrode(GCE) exhibited excellent electrocatalytic activity for the oxidation of dopamine(DA) with a detection limit of 100 nmol/L(S/N = 3). In addition, the FePt/DNA-rGO based electrochemical sensor showed an excellent selectivity for DA in the presence of ascorbic acid(AA), uric acid(UA) and other interference reagents. The as-prepared electrochemical biosensor shows great promise in the application of clinical diagnostics.  相似文献   

14.
《Electroanalysis》2017,29(2):587-594
A sensitive and selective hydrazine sensor was developed by β‐cyclodextrin modified palladium nanoparticles decorated reduced graphene oxide (PdNPs‐β‐CD/rGO) nanocomposite. The PdNPs‐β‐CD/rGO hybrid material was prepared by simple electrochemical method. The hydrophobic cavity of β‐CD ineracts with palladium nanoparticles by hydrophobic interaction and further it is uniformly assembled on the rGO surface through hydrogen bond formation, which is clearly confirmed by FT‐IR, FESEM and TEM. The high electrocatalytic activity of hydrazine oxidation was observed at −0.05 V (vs. Ag/AgCl) on PdNPs‐β‐CD/rGO modified electrode; due to the excellent stabilization, high catalytic activity and large surface area of the PdNPs‐β‐CD/rGO composite. The PdNPs‐β‐CD/rGO fabricated hydrazine sensor exhibited an excellent analytical performance, including high sensitivity (1.95 μA μM−1 cm−2), lower detection limit (28 nM) and a wide linear range (0.05 to 1600 μM). We also demonstrated that the PdNPs‐β‐CD/rGO nanocomposite modified electrode is a highly selective and sensitive sensor towards detection of hydrazine among the various interfering species. Hence, the proposed hydrazine sensor is able to determine hydrazine in different water samples.  相似文献   

15.
A new nanocomposite, poly(aniline‐co‐diphenylamine‐4‐sulfonic acid)/graphene (PANISP/rGO), was prepared by means of an in situ oxidation copolymerization of aniline (ANI) with diphenylamine‐4‐sulfonic acid (SP) in the presence of graphene oxide, followed by the chemical reduction of graphene oxide using hydrazine hydrate as a reductant. The morphology and structure of PANISP/rGO were characterized by field‐emission (FE) SEM, TEM, X‐ray photoelectron spectroscopy (XPS), Raman, FTIR, and UV/Vis spectra. The electrochemical performance was evaluated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The PANISP/rGO nanocomposite showed a nanosized structure, with sulfonic polyaniline nanoarrays coated homogeneously on the surface of graphene nanosheets. This special structure of the nanocomposite also facilitates the enhancement of the electrochemical performance of the electrodes. The PANISP/rGO nanocomposite exhibits a specific supercapacitance up to 1170 F g?1 at the current density of 0.5 A g?1. The as‐prepared electrodes show excellent supercapacitive performance because of the synergistic effects between graphene and the sulfonic polyaniline copolymer chains.  相似文献   

16.
A novel ternary nanocomposite, Pd nanoparticles(NPs)/polyoxometalates(POMs)/reduced graphene oxide(rGO), was prepared by a green, mild, electrochemical-reductionassisted assembly. It is worth noting that the Keggin-type POM acts as an electrocatalyst as well as a bridging molecule. During the reduction process, POMs transfer the electrons from the electrode to GO, leading to a deep reduction of GO and the content of oxygen-containing groups is decreased to around 6.1%. Meanwhile, the strong adsorption effect between the POM clusters and rGO nanosheets induces the spontaneous assembly of POM on r GO in a uniformly dispersed state, forming a nanocomposite. The ternary Pd NPs/POMs/rGO nanocomposite exhibits higher electrocatalytic activities, better electrochemical stability, and higher resistance to CO poisoning than the Pd/C catalyst towards the formic acid oxidation(FAOR). Especially, the Pd/PW_(12)/rGO exhibits the best electrocatalytic performance among three Pd/POMs/rGO composites(POMs = PW_(12), SiW_(12), PMo_(12)).  相似文献   

17.
The electrochemical synthesis of silver nanoparticles (nano‐Ag) has been successfully carried out on glassy carbon electrode (GCE) and indium tin oxide electrode (ITO) using 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMT) as green electrolytes. Further the electrodeposited nano‐Ag modified ITO electrode has been examined using atomic force microscopy (AFM), and X‐ray diffraction studies (XRD). The electrodeposited Ag nanoparticles on ITO were found in the size range of 5 to 35 nm. The nano‐Ag film modified GCE was further coated with nafion (Nf) and BMT (1 : 1 ratio) mixture and found to be stable in BMT and in pH 7 phosphate buffer solution (PBS). The nano‐Ag/BMT‐Nf film modified GCE successfully applied for the oxygen reduction reaction in neutral pH (pH 7.0 PBS). The proposed film modified GCE successfully reduces the over potential and show well defined reduction peaks for the detection of dissolved oxygen using cyclic voltammetry (CV) and rotating disc voltammetry (RDE). The film also applied for the detection of dissolved oxygen using electrochemical impedance spectroscopic studies (EIS).  相似文献   

18.
In this study, we present a novel approach to prepare of a colorimetric chemical sensor for H2O2 and a glucose biosensor basing on the use of peroxidase-like activity of silver nanoparticles decorated on reduced graphene oxide sheets (AgNPs@rGO) nanocomposite. Herein, AgNPs@rGO nanocomposite was synthesized by a one-step hydrothermal reducing method and its physico-chemical properties were characterized by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Ultraviolet–visible spectroscopy (UV–Vis), Fourier-Transform Infrared spectroscopy (FT-IR) and Energy Dispersive X-ray spectroscopy (EDX). Obtained evaluation results shown that the synthesized AgNPs/rGO nanocomposite has performed an efficient peroxidase-like activity for the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMBred) by H2O2, leading to the oxidized form (TMBox) which presents a typical blue color (maximum of absorbance at λmax = 655 nm). A colorimetric assay for H2O2 detection was designed and fabricated with a limit of detection of 20 μM. Moreover, we have used of AgNPs/rGO nanocomposite combining with glucose oxidase (GOx) to develop of a colorimetric glucose biosensor with a low limit of detection of 40 μM and a linear dynamic range from 125 μM to 1 mM. This glucose test was applied to the detection of glucose in human serum samples.  相似文献   

19.
The electrochemical depositions of Pt microparticles and KI film were successfully carried out on glassy carbon electrodes (GCE), gold electrodes (GE), and indium tin oxide electrodes (ITO). The electrochemical studies of Pt micro/KI film on GCE show that the film was stable, active at pH 1.5 electrolyte solutions. The Pt microparticle/KI film modified ITO electrodes were examined by using scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The SEM and AFM results show that the Pt particle sizes were in the range of 120 nm–1.4 μm, respectively. The proposed film on GCE shows efficient electrocatalysis for oxygen, Cr2O reduction by using cyclic voltammetry. Further the electrochemical oxidation of sodium meta‐arsenite (As(III)), H2O2 were successfully carried out and the detection of H2O2 in real samples has been validated.  相似文献   

20.
We report for the first time a microwave assisted, one pot, direct, and facile synthesis of monodispersed iron‐gold bimetallic nanoparticles (BNPAu‐Fe) using glucose as a reducing agent in merely 90 s. The as such synthesized BNPAu‐Fe were thoroughly characterized using UV‐Vis, XRD, TEM, EDX, elemental mapping, and raman spectroscopy. These BNPAu‐Fe were further impregnated with reduced graphene oxide (rGO) and coated onto glassy carbon electrode (GCE) to develop a sensor probe for label free electrochemical detection of acetaminophen, which is considered to be a most potent biomarker related to non‐alcoholic fatty liver disease. The sensor probe was systematically characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The BNPAu‐Fe‐rGO nanocomposite matrix showed the sensing of acetaminophen with a wide dynamic range between 50 and 800 nM with detection limit (DL) of 0.14 nM (±0.05) nM (RSD<4.12 %) that was lower compared to previously reported acetaminophen sensors. To show the practical application of the sensor probe, acetaminophen was detected in human urine samples, which showed the percentage recovery between 86.65 % and 91.32 %. To the best of our knowledge, this is the first report where BNPAu‐Fe impregnated rGO was used to detect acetaminophen. Interferences due to various molecules such as glucose, serum albumin, glycine, glutamic acid, alanine, citric acid, and ascorbic acid were tested individually and in mixed sample. Long‐term stability of sensor probe was examined which was found to be stable up to 12 weeks. The sensor fabricated using BNPAu‐Fe‐rGO nanocomposite has many attractive features such as; simplicity, rapidity, and label free detection, hence it could be a method of choice for acetaminophen detection in clinical settings.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号