Electrochemical properties of core-shell TiC-TiO2 nanoparticle films immobilized at ITO electrode surfaces

Titanium carbide (TiC) nanoparticles are readily deposited onto tin-doped indium oxide (ITO) electrodes in the form of thin porous films. The nanoparticle deposits are electrically highly conducting and electrochemically active. In aqueous media (at pH 7) and at applied potentials positive of 0.3 V vs. SCE partial anodic surface oxidation and formation (at least in part) of novel core-shell TiC-TiO2 nanoparticles is observed. Significant thermal oxidation of TiC nanoparticles by heating in air occurs at a temperature of 250 degrees C and leads first to core-shell TiC-TiO2 nanoparticles, next at ca. 350 degrees C to TiO2 (anatase), and finally at temperatures higher than 750 degrees C to TiO2 (rutile). Electrochemically and thermally partially oxidized TiC nanoparticles still remain very active and for some redox systems electrocatalytically active. Scanning and transmission electron microscopy (SEM and TEM), temperature dependent XRD, quartz crystal microbalance, and voltammetric measurements are reported. The electrocatalytic properties of the core-shell TiC-TiO2 nanoparticulate films are surveyed for the oxidation of hydroquinone, ascorbic acid, and dopamine in aqueous buffer media. In TiC-TiO2 core-shell nanoparticle films TiO2 surface reactivity can be combined with TiC conductivity.     

Silver-nanoparticle-attached indium tin oxide surfaces fabricated by a seed-mediated growth approach

By applying a seed-mediated growth method that had been reported for the chemical synthesis of Ag nanorods and nanowires in aqueous solution, we successfully attached Ag nanosphere and nanorod particles to indium tin oxide (ITO) surfaces. In this method, it is characteristic that the attachment can be performed without using bridging reagents, such as 3-mercaptopropyltrimethoxysilane, but rather through a two-step immersion into the seed solution first and then into the growth solution containing AgNO(3), cetyltrimethylammonium bromide, and ascorbic acid. It was found that the formed nanostructures were very sensitive to the amount of ascorbic acid in the growth solution. Whereas Ag nanoparticles grew on the ITO surface with a moderate dispersion when the concentration of ascorbic acid in the growth solution was 0.64 mM, the formation of nanorods and nanowires was observed when the ascorbic acid concentration was increased to 0.86 mM. The attachment of Ag nanoparticles onto the ITO surfaces was strong enough for further use, e.g., as a working electrode. From electrochemical measurements, it was confirmed that the outer spheres of the Ag nanoparticles involved in the redox reaction show the typical oxidation and reduction waves of Ag. In addition, the redox behavior of [Fe(CN)(6)](3-)/[Fe(CN)(6)](4-) was improved on the Ag-nanoparticle-attached ITO (AgNP/ITO) electrode, reflecting the low electron-transfer resistivity, which is a remarkable advantage of the present fabrication without using bridging reagents. This result indicated that the Ag nanoparticles promote the electron-transfer reactions by being present on the conducting ITO surface. The AgNP/ITO electrode was examined for the reduction of the methyl viologen dication in order to discuss some features of the present fabrication.     

Hemoglobin adsorption into TiO2 phytate multi-layer films: particle size and conductivity effects

Hemoglobin (molecular weight 64.5 kDa, isoelectric point 7.4) in 0.1 M phosphate buffer solution at pH 5.5 readily adsorbs onto mesoporous TiO₂ phytate films, which have been formed in a layer-by-layer deposition process from TiO₂ nanoparticles (ca. 6–10 nm diameter) and phytic acid at tin-doped indium oxide (ITO) electrodes. Quartz crystal microbalance data, voltammetry, and SEM evidence are consistent with hemoglobin adsorption only into the outer TiO₂ phytate surface layer. The size of the tetrametric hemoglobin protein (ca. 6 nm diameter) appears to be too big for a homogeneous film to form.The modified ITO electrode immersed in 0.1 M phosphate buffer solution at pH 5.5 allows reversible electron transfer for hemoglobin to be observed with a midpoint potential of 0.01 vs. SCE. Characteristic TiO₂ phytate film thickness and pH effects are observed with both thicker films and lower proton activity causing ‘decoupling’ of the protein redox chemistry due to a reduced electrical conductivity of the TiO₂ phytate film connecting hemoglobin with the electrode. This is the first example of a bi-layer nanofilm structure where the underlying TiO₂ phytate film controls the electrochemical properties of the hemoglobin modified top-layer.     

A novel ferroceneylazobenzene self-assembled monolayer on an ITO electrode: photochemical and electrochemical behaviors

A novel ferroceneylazobenzene self-assembled monolayer (SAM) has been constructed on an indium-tin oxide (ITO) electrode via the covalent attachment of 4-(4'-11-ferrocenyl-undecanoxyphenylazo)benzoic acid ( FcAzCOOH) onto a silanized ITO substrate surface and verified by reflectance infrared spectroscopy and water contact angle. Atomic force microscopy (AFM) and cyclic voltammogram (CV) indicated that the FcAzCOOH formed a uniform and reproducible SAM on the ITO electrode with a surface coverage of ca. 1.9 x 10 (-10) mol/cm (2) (87 A (2)/molecule). The reversible photoisomerization behavior of the SAM was characterized by UV-vis spectra. The azo pi-pi* transition band intensity of the SAM gradually decreased with UV (365 nm) irradiation and was almost recovered again when subsequent exposure to ambient room light (400-800 nm). The increased tilt angle of the molecules on the ITO substrate after UV irradiation further confirmed the trans-to- cis isomerization of azobenzene moieties. The CV of the trans- FcAzCOOH modified ITO electrode showed a pair of waves due to redox of the ferrocene groups in the potential range of 0 to +800 mV (vs SCE), and the peak separation of the redox wave became larger after UV irradiation and almost returned to its original value after subsequent exposure to the visible light. Rate-dependent CV curves indicated that the charge transfer rate between the ferrocene species in the SAM and the ITO electrode was slowed down after UV irradiation due to the smaller porosity of the monolayer film and the more compact barrier layer between the redox species and the ITO electrode. It is the first time to directly observe the influence of photoisomerization of the azobenzene moiety on the redox behavior of redox species in the ferroceneylazobenzene-functionalized SAM. The present results provide profound insight into the role of redox microenvironment on electron transfer kinetics and also provide a simple and facile approach to the preparation of photocontrollable electrodes.     

Enhanced charge transport and incorporation of redox mediators in layer-by-layer films containing PAMAM-encapsulated gold nanoparticles

In this work, we exploit the molecular engineering capability of the layer-by-layer (LbL) method to immobilize layers of gold nanoparticles on indium tin oxide (ITO) substrates, which exhibit enhanced charge transfer and may incorporate mediating redox substances. Polyamidoamine (PAMAM generation 4) dendrimers were used as template/stabilizers for Au nanoparticle growth, with PAMAM-Au nanoparticles serving as cationic polyelectrolytes to produce LbL films with poly(vinylsulfonic acid) (PVS). The cyclic voltammetry (CV) of ITO-PVS/PAMAM-Au electrodes in sulfuric acid presented a redox pair attributed to Au surface oxide formation. The maximum kinetics adsorption is first-order, 95% of the current being achieved after only 5 min of adsorption. Electron hopping can be considered as the charge transport mechanism between the PVS/PAMAM-Au layers within the LbL films. This charge transport was faster than that for nonmodified electrodes, shown by employing hexacyanoferrate(III) as the surface reaction marker. Because the enhanced charge transport may be exploited in biosensors requiring redox mediators, we demonstrate the formation of Prussian blue (PB) around the Au nanoparticles as a proof of principle. PAMAM-Au@PB could be easily prepared by electrodeposition, following the ITO-PVS/ PAMAM-Au LbL film preparation procedure. Furthermore, the coverage of Au nanoparticles by PB may be controlled by monitoring the oxidation current.     

Electrochemical control of protein monolayers at indium tin oxide surfaces for the reagentless optical biosensing of nitric oxide

Cytochrome c has been immobilized onto functionalized, optically transparent indium tin oxide (ITO) electrodes by covalent and electrostatic techniques. Covalent immobilization was achieved by the formation of a disulfide bond between N-succinimidyl 3-(2-pyridyldithio)propionate-(SPDP-) modified cytochrome c and SPDP-silanized ITO. Additionally, ITO electrodes have been modified with the bifunctional reagent 1,12-dodecanedicarboxylic acid (DDCA), resulting in formation of a carboxylic acid-terminated monolayer. Covalent protein attachment to the DDCA-functionalized ITO was achieved with the cross-linker 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride. Electrostatic attachment of the protein involved ion-pair and hydrogen-bond interactions between the terminating carboxylic acid groups of the DDCA-functionalized ITO and the primary amine groups of the lysine residues of cytochrome c. The electrostatic interaction between the cytochrome c and the functionalized ITO resulted in greater rotational mobility of the protein at the electrode surface, leading to ca. 63% electroactivity, as compared to ca. 41% electroactivity for the covalently immobilized protein. The redox state of the electrostatically bound cytochrome c monolayers could be electrochemically switched between ferric and ferrous forms. Electrochemical control of the bound protein was used to regenerate the biosensing surface following binding of nitric oxide (NO). Ligation of NO with the cytochrome c was monitored by measurement of the change of absorbance intensity at 416 nm. Through application of a negative potential, the cytochrome c was reduced from the ferric to the ferrous form, which led to the removal of the ligated NO. Application of a positive potential regenerated the ferric cytochrome c, enabling multiple repeat measurements of NO. Such electrochemical control of proteins immobilized on transparent electrodes enables the optical biosensing of analyte targets without recourse to exogenous reagents.     

Gold nanoparticle arrays directly grown on nanostructured indium tin oxide electrodes: Characterization and electroanalytical application

This work describes an improved seed-mediated growth approach for the direct attachment and growth of mono-dispersed gold nanoparticles on nanostructured indium tin oxide (ITO) surfaces. It was demonstrated that, when the seeding procedure of our previously reported seed-mediated growth process on an ITO surface was modified, the density of gold nanospheres directly grown on the surface could be highly improved, while the emergence of nanorods was restrained. By field emission scanning electron microscopy (FE-SEM) and cyclic voltammetry, the growth of gold nanoparticles with increasing growth time on the defect sites of nanostructured ITO surface was monitored. Using a [Fe(CN)₆]³⁻/[Fe(CN)₆]⁴⁻ redox probe, the increasingly facile heterogeneous electron transfer kinetics resulting from the deposition and growth of gold nanoparticle arrays was observed. The as-prepared gold nanoparticle arrays exhibited high catalytic activity toward the electrooxidation of nitric oxide, which could provide electroanalytical application for nitric oxide sensing.     

静电纺丝法制备纳米氧化铟锡及其导电性能

采用静电纺丝-溶胶凝胶法,以SnCl2、InCl3、聚乙烯吡咯烷酮(PVP)等为原料,乙醇胺为水解控制剂,合成了超细氧化铟锡(ITO)纳米纤维及富氧缺陷的ITO纳米颗粒.采用透射电子显微镜(TEM)、选区电子衍射(SAED)、扫描电子显微镜(SEM)、热重分析(TGA)、X射线衍射(XRD)、X射线电子能谱(XPS)、...     

Tuning percolation speed in layer-by-layer assembled polyaniline�Cnanocellulose composite films

Polyaniline of low molecular weight (ca. 10?kDa) is combined with cellulose nanofibrils (sisal, 4?C5?nm average cross-sectional edge length, with surface sulphate ester groups) in an electrostatic layer-by-layer deposition process to form thin nano-composite films on tin-doped indium oxide (ITO) substrates. AFM analysis suggests a growth in thickness of ca. 4?nm per layer. Stable and strongly adhering films are formed with thickness-dependent coloration. Electrochemical measurements in aqueous H₂SO₄ confirm the presence of two prominent redox waves consistent with polaron and bipolaron formation processes in the polyaniline?Cnanocellulose composite. Measurements with a polyaniline?Cnanocellulose film applied across an ITO junction (a 700?nm gap produced by ion beam milling) suggest a jump in electrical conductivity at ca. 0.2?V vs. SCE and a propagation rate (or percolation speed) two orders of magnitude slower compared to that observed in pure polyaniline This effect allows tuning of the propagation rate based on the nanostructure architecture. Film thickness-dependent electrocatalysis is observed for the oxidation of hydroquinone.     

Pd纳米粒子敏化的纳米单层TiO_2-Ru(Ⅱ)螯合物修饰电极对单磷酸鸟苷的电催化氧化行为

利用LB膜技术可控制备了纳米单层的二氧化钛-有机钌螯合物杂化膜,并研究了上述无机-有机杂化膜修饰电极在Pd纳米粒子敏化后对单磷酸鸟苷(GMP)的电催化氧化行为.实验结果表明:(1)纳米单层TiO2/[Ru(phen)2(dC18bpy)]2+(简称为TiO2-Ru)杂化膜的平均厚度为(3.2±0.5)nm;(2)在光照条件下TiO2-Ru杂化膜能有效催化还原[Pd(NH3)4]2+形成粒径位于20～200nm之间的Pd纳米粒子;(3)纳米单层TiO2-Ru/Pd杂化膜能高效催化氧化具有供电子能力的单磷酸鸟苷(GMP),与纳米单层TiO2-Ru杂化膜修饰的ITO电极(ITO/TiO2-Ru)相比,当工作电压为1200mV时,ITO/TiO2-Ru/Pd电极在含有1×10-3molL-1GMP的磷酸盐缓冲液中,单位面积的催化氧化电流提高了约36倍;(4)Pd纳米粒子的引入消除了金属钌螯合物中配体对电子传递的阻碍作用,改变了电子传递途径,从而有效减少了电子空穴对的复合,提高了杂化膜修饰电极(ITO/TiO2-Ru/Pd)的电子传递效率.     

Seed-mediated growth of palladium nanocrystals on indium tin oxide surfaces and their applicability as modified electrodes

Palladium nanoparticles (PdNPs) were successfully attached and grown on an indium tin oxide (ITO) surface using a seed-mediated growth method, i.e., via a simple two-step immersion of the ITO substrate into the seed and growth solutions. After the growth treatment for 24 h, PdNPs grew up to 60-80 nm, exhibiting crystal-like appearances and accompanying the formation of short rodlike nanocrystals as a minor product. Thus prepared PdNPs tend to stick each other, so that the dense gathering of PdNPs was observed on the ITO surfaces. Due to the dense attachment, the PdNPs directly attached to the ITO (PdNP/ITO) electrode had a significantly lowered charge-transfer resistivity compared with that of a bare ITO, and the redox reaction of [Fe(CN)6]3-/[Fe(CN)6]4- was observed as reversible in 0.1 M phosphate buffer solution. The electrocatalytic property of PdNPs was confirmed for the reduction of oxygen. In addition, some typical responses were observed in 0.5 M H2SO4 with the PdNP/ITO electrode, reflecting both the characteristics of NPs and the thin layer in nanoscale. The present preparation method of PdNP-attached surfaces would be promising for catalytic applications as well as electrochemical uses.     

Magnetoswitchable electrochemistry gated by alkyl-chain-functionalized magnetic nanoparticles: control of diffusional and surface-confined electrochemical processes

Magnetic nanoparticles consisting of undecanoate-capped magnetite (average diameter ca. 5 nm) are used to selectively gate diffusional and surface-confined electrochemical reactions. A two-phase system consisting of an aqueous buffer solution and a toluene phase that includes the suspended undecanoate-capped magnetic nanoparticles is used to control the interfacial properties of the electrode surface. Two different phenomena are controlled by attraction of the magnetic nanoparticles to the electrode by means of an external magnet: (i) The attracted magnetic nanoparticles form a hydrophobic layer on the electrode surface resulting in the blocking of diffusional electrochemical processes, while retaining the redox functions of surface-confined electrochemical units. (ii) For certain surface-immobilized redox species (e.g., quinones), the attraction of the magnetic nanoparticles to the electrode surface alters the mechanism of the process from an aqueous-type electrochemistry to a dry organic-phase-type electrochemistry. Also, bioelectrocatalytic and electrocatalytic transformations at the electrode are controlled by means of attraction of the magnetic nanoparticles to the electrode surface. Controlling the catalytic functions of the modified electrode by means of the magnetic nanoparticles attracted to the electrode is exemplified in two different directions: (i) Blocking of the bioelectrocatalyzed oxidation of glucose by glucose oxidase (GOx) using a surface-confined ferrocene monolayer as electron-transfer mediator. (ii) Activation of the microperoxidase-11 electrocatalyzed reduction of cumene hydroperoxide. In the latter system, the hydrophobic magnetic nanoparticles adsorb toluene, and the hydrophobic matrix acts as a carrier for cumene hydroperoxide to the electrode surface modified with the microperoxidase-11 catalyst.     

New method for preparation of polyoxometalate-capped gold nanoparticles, and their assembly on an indium-doped tin oxide electrode

Functionalized gold nanoparticles capped with polyoxometalates were prepared by a simple photoreduction technique where phosphododecamolybdates serve as reducing reagents, photocatalysts, and as stabilizers. TEM images of the resulting gold nanoparticles show the particles to have a relative narrow size distribution. Monolayer and multilayer structures of the negatively charged capped gold nanoparticles were deposited on a poly(vinyl pyridine)-derivatized indium-doped tin oxide (ITO) electrode via the layer-by-layer technique. The surface plasmon resonance band of the gold nanoparticles displays a blue shift on the surface of the ITO electrode. This is due to the substrate-induced charge redistribution in the gold nanoparticles and a change in the electromagnetic coupling between the assembled nanoparticles. The modified electrode exhibits the characteristic electrochemical behavior of surface-confined phosphododecamolybdate and excellent electrocatalytic activity. The catalysis of the modified electrode towards the model compound iodate was systematically studied. The heterogeneous catalytic rate constant for the electrochemical reduction of iodate was determined by chronoamperometry to be ca. 1.34?×?10⁵ mol^?1·L·s^?1. The amperometric method gave a linear range from 2.5?×?10^?6 to 1.5?×?10^?3 M and a detection limit of 1.0?×?10^?6 M. We believe that the functionalized gold nanoparticles prepared by this photoreduction technique are advantageous in terms of fabrication of sensitive and stable redox electrodes.

Tuning percolation speed in layer-by-layer assembled polyaniline–nanocellulose composite films

Polyaniline of low molecular weight (ca. 10 kDa) is combined with cellulose nanofibrils (sisal, 4–5 nm average cross-sectional edge length, with surface sulphate ester groups) in an electrostatic layer-by-layer deposition process to form thin nano-composite films on tin-doped indium oxide (ITO) substrates. AFM analysis suggests a growth in thickness of ca. 4 nm per layer. Stable and strongly adhering films are formed with thickness-dependent coloration. Electrochemical measurements in aqueous H₂SO₄ confirm the presence of two prominent redox waves consistent with polaron and bipolaron formation processes in the polyaniline–nanocellulose composite. Measurements with a polyaniline–nanocellulose film applied across an ITO junction (a 700 nm gap produced by ion beam milling) suggest a jump in electrical conductivity at ca. 0.2 V vs. SCE and a propagation rate (or percolation speed) two orders of magnitude slower compared to that observed in pure polyaniline This effect allows tuning of the propagation rate based on the nanostructure architecture. Film thickness-dependent electrocatalysis is observed for the oxidation of hydroquinone.

     

Ultrathin Carbon Nanoparticle Composite Film Electrodes: Distinguishing Dopamine and Ascorbate

Ultrathin carbon nanoparticle–poly(diallyldimethylammonium chloride) films (CNP‐PDDAC films) are formed on tin‐doped indium oxide (ITO) electrodes in a layer‐by‐layer electrostatic deposition process employing 9–18 nm diameter carbon particles. Transparent and strongly adhering films of high electrical conductivity are formed and characterized in terms of their electrochemical reactivity. When immersed in aqueous 0.1 M phosphate buffer pH 7, each layer of CNP‐PDDAC (of ca. 5–6 nm average thickness) is adding an interfacial capacitance of ca. 10 μF cm^?2. Absorption into the CNP–PDDAC nanocomposite film is dominated by the sites in the PDDAC cationomer and therefore anionic molecules such as indigo carmine are strongly bound and retained within the film (cationic binding sites per layer ca. 150 pmol cm^?2). In contrast, cationic redox systems such as ferrocenylmethyltrimethyl‐ammonium⁺ fail to bind. For solution phase redox systems such as hydroquinone, the rate of electron transfer is dramatically affected by the CNP‐PDDAC film and switched from completely irreversible to highly reversible even with a single layer of carbon nanoparticles. For the mixed redox system ascorbate–dopamine in 0.1 M phosphate buffer pH 7 cyclic voltammograms suggest a rapid and selective temporary poisoning process which causes the ascorbate oxidation to be suppressed in the second potential cycle. This effect is exploited for the detection of micromolar concentrations of dopamine in the presence of millimolar ascorbate.     

可见光响应Bi2WO6薄膜的制备与光电化学性能

采用非晶态配合物-提拉法在ITO导电玻璃基底上制备得到Bi2WO6薄膜. 采用FE-SEM、XRD、Raman、DRS、光电流响应谱、IPCE等手段, 研究了Bi2WO6薄膜的形貌、结构、光电性能以及薄膜结构与光电性能的关系. 结果表明, 450 ℃以上煅烧可以得到Bi2WO6结晶薄膜, 薄膜由沿(131)晶面趋向生长的Bi2WO6纳米颗粒组成, 颗粒的粒度随煅烧温度的升高而增大, 同时颗粒之间的间距也相应增大. ITO/Bi2WO6薄膜电极在可见光(λ>400 nm)照射下可以产生光电流, 光电流强度与光强度线性相关; 光电流强度和光电转换量子效率受Bi2WO6薄膜结构的影响, 通过控制薄膜的煅烧温度等制备条件, 可以提高薄膜光电极的光电转换量子效率.     

TiO2与ZnO复合纳米结构电极的光电化学研究

利用尿素加压共沉淀法以Ti(SO4)2与Zn(NO3)2为原料制备了TiO2-ZnO复合纳米粒子, 其纳米结构电极的光电化学研究结果表明, 反应物摩尔比为3∶1, 于530 ℃煅烧制备的复合纳米结构电极的光电转换效率最高. 对吸附染料RuL2(SCN)2∶2TBA的纳米结构TiO2和各种复合纳米粒子的纳米结构电极进行光电研究的结果表明, 染料对各纳米结构电极都起到了敏化作用, 其中也是由反应物摩尔比为3∶1, 于530 ℃煅烧制备的纳米结构电极的光电转换效率最高. 对聚3-甲基噻吩修饰的纳米结构TiO2和摩尔比为3∶1, 于530 ℃煅烧的复合纳米粒子构成的纳米结构电极进行光电性能研究, 结果表明, 聚3-甲基噻吩与半导体纳米粒子之间存在p-n结, 在一定条件下p-n结的存在有利于光生电子/空穴的分离, 从而提高了光电转化效率.     

Investigation of p-hydroxybenzoic acid from a new surface-enhanced Raman scattering system

In this paper, we developed a new kind of substrate, silver-coated indium tin oxide (ITO), to investigate the character of surface-enhanced Raman scattering (SERS) of p-hydroxybenzoic acid (PHBA). Homogeneous Ag-coated ITO substrate was obtained by decomposing AgNO(3) on the surface of ITO. A SERS spectrum of very good quality of "silver nanoparticles/PHBA/silver-coated ITO" was reported by adding PHBA aqueous solution and silver colloid onto the surface of silver-coated ITO repeatedly. PHBA molecules absorbed onto the surface of the silver nanoparticles through ionized carboxyl, and the PHBA molecules tended to tilt on the surface in this system. The rich information obtained from the silver nanoparticles/PHBA/silver-coated ITO system indicates that this is a highly SERS-active system. Not only was the number of the vibrational modes increased, but also were the frequencies of Raman bands shifted. The two SERS mechanisms, the "electromagnetic" and "chemical" mechanism, were mainly responsible for the experimental results. Furthermore, the silver nanoparticles modified on the silver-coated ITO surface play an important role in magnifying the surface local electric field near the silver film surface through resonant surface plasmon excitation.     

Dioctylamine‐Sulfonamide‐Modified Carbon Nanoparticles as High Surface Area Substrates for Coenzyme Q10?Lipid Electrochemistry

Dioctylaminesulfonamide‐modified carbon nanoparticles are characterised and employed as high surface area substrate for (i) coenzyme Q10 and (ii) 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphocholine (or DMPC) ‐ Q10 redox processes. The carbon nanoparticles provide a highly hydrophobic substrate with ca. 25 Fg^?1 capacitance when bare. Q10 or DMPC‐Q10 immobilised onto the carbon nanoparticles lower the capacitance, but give rise to well‐defined pH‐dependent voltammetric responses. The DMPC‐Q10 deposit shows similar characteristics to those of Q10, but with better reproducibility and higher sensitivity. Both redox systems, Q10 and DMPC‐Q10, are sensitive to the Na⁺ concentration in the electrolyte and mechanistic implications are discussed.     

微接触印刷技术转移Au纳米粒子及氧化石墨烯复合图案及其性质研究

通过改良的“Hummers方法”制得氧化石墨烯,利用聚二甲基硅氧烷（PDMS）弹性印章的微接触印刷技术,以Au膜和氧化石墨烯溶液为“墨水”,通过二次印章转移,分别将Au纳米粒子和氧化石墨烯（Graphene Oxide,GO）转移至修饰了(3-氨基丙基)三乙氧基硅烷（APTES）的ITO基底（APTES/ITO）表面. 利用场发射扫描电子显微镜（FE-SEM）、原子力显微镜（AFM）等表征图案,结果表明转移的AuNPs和GO组成的复合图案均匀,致密性较好. 利用表面电势显微镜（Surface Potential Microscope,SEPM,KFM）测定了各部分的表面电势,以APTES/ITO基底表面为表面电势零点,各部分表面电势大小为：APTES/ITO > GO > Au（0,-11.6,-44.2 mV）.