Electrochemically assisted fabrication of size-exclusion films of organically modified silica and application to the voltammetry of phospholipids

Modification of electrodes with nanometer-scale organically modified silica films with pore diameters controlled at 10- and 50-nm is described. An oxidation catalyst, mixed-valence ruthenium oxide with cyano cross-links or gold nanoparticles protected by dirhodium-substituted phosphomolybdate (AuNP-Rh₂PMo₁₁), was immobilized in the pores. These systems comprise size-exclusion films at which the biological compounds, phosphatidylcholine and cardiolipin, were electrocatalytically oxidized without interference from surface-active concomitants such as bovine serum albumin. Ten-nanometer pores were obtained by adding generation-4 poly(amidoamine) dendrimer, G4-PAMAM, to a (CH₃)₃SiOCH₃ sol. Fifty-nanometer pores were obtained by modifying a glassy carbon electrode (GC) with a sub-monolayer film of aminopropyltriethoxylsilane, attaching 50-nm diameter poly(styrene sulfonate), PSS, spheres to the protonated amine, transferring this electrode to a (CH₃)₃SiOCH₃ sol, and electrochemically generating hydronium at uncoated GC sites, which catalyzed ormosil growth around the PSS. Voltammetry of Fe(CN)₆ ^3? and Ru(NH₃)₆ ³⁺ demonstrated the absence of residual charge after removal of the templating agents. With the 50-nm system, the pore structure was sufficiently defined to use layer-by-layer electrostatic assembly of AuNP-Rh₂PMo₁₁ therein. Flow injection amperometry of phosphatidylcholine and cardiolipin demonstrated analytical utility of these electrodes.     

Characterization and Electrocatalytic Property of Cobalt Hexacyanoferrate Film on Carbon Nanotubes Modified Gold Electrode

Abstract

Cobalt hexacyanoferrate (CoHCF) film was formed on multiwalled carbon nanotubes (MWNTs) modified gold electrode by electrodeposition from 0.5 M KCl solution containing CoCl₂ and K₃Fe(CN)₆. The electrochemical behavior and the electrocatalytic property of the modified electrode were investigated. Compared with CoHCF/gold electrode, the CoHCF/MWNTs/gold electrode exhibits greatly improved stability and enhanced electrocatalytic activity toward the oxidation of thiosulfate. A linear range from 5.0×10^?5 to 6.5×10^?3 M (r=0.9990) for thiosulfate detection at the CoHCF/MWNTs/gold electrode was obtained, with a detection limit of 2.0×10^?5 M (S/N=3).     

Preparation of a cobalt hexacyanoferrate film-modified aluminum electrode by chemical and electrochemical methods: enhanced stability of the electrode in the presence of phosphate and ruthenium(III)

Modification of an aluminum electrode by means of a thin film of cobalt hexacyanoferrate (CoHCF) using electroless and electrochemical procedures is described. The modification conditions of the aluminum surface, including the electroless deposition of metallic cobalt on the electrode surface from CoCl₂+NaF solution and the chemical derivatization of the deposited cobalt to give a CoHCF film in 0.25 M KCl+0.25 M K₃[Fe(CN)₆] solution, have been determined. The modified Al electrodes prepared under optimum conditions show one or two well-defined redox couples in phosphate buffer solutions of pH 7.2, depending on the preparation procedure, due to the [Co^IIFe^III/II(CN)₆]^–/2– system. The effect of pH, alkali metal cations, and anions of the supporting electrolyte on the electrochemical characteristics of the modified electrode were studied. Diffusion coefficients of hydrated Na⁺ in the film, the transfer coefficient, and the transfer rate constant for electrons were determined. The stability of the modified electrodes under various experimental conditions was studied and their high stability in the sodium phosphate buffer solutions was confirmed. Enhanced stability was observed when the modified electrode was scanned in fresh solutions of RuCl₃ between 0 and 1 V for at least 20 cycles, due to the formation of mixed hexacyanoferrates of cobalt and ruthenium. Electronic Publication     

Analytical Biosensing of Hydrogen Peroxide on Brilliant Cresyl Blue/Multiwalled Carbon Nanotubes Modified Glassy Carbon Electrode

A cationic quinine‐imide dye brilliant cresyl blue (BCB) and horseradish peroxidase (HRP) were co‐immobilized within ormosil on multiwalled carbon nanotubes modified glassy carbon electrode for the fabrication of highly sensitive and selective hydrogen peroxide biosensor. The presence of epoxy group in ormosil as organic moiety improves the mechanical strength and transparency of the film and amino group provides biocompatible microenvironment for the immobilization of enzyme. The presence of MWCNTs improved the conductivity of the nanocomposite film. The surface characterization of MWCNT modified ormosil nanocomposite film was performed with scanning electron microscopy (SEM) and atomic force microscopy (AFM). Cyclic voltammetry and amperometry measurements were used to study and optimize the performance of the resulting peroxide biosensor. The apparent Michaelis–Menten constant was determined to be 1.5 mM. The proposed H₂O₂ biosensor exhibited wide linear range from 3×10^?7 to 1×10^?4 M, and low detection limit 1×10^?7 M (S/N=3) with fast response time <5 s. The probable interferences in bio‐matrix were selected to test the selectivity and no significant response was observed in the biosensor. This biosensor possessed good analytical performance and long term storage stability.     

Novel proton-conductive nanochannel membranes with modified SiO2 nanospheres for direct methanol fuel cells

A novel approach is proposed to prepare a proton-conductive nanochannel membrane based on polyvinylidene difluoride (PVDF) porous membrane with modified SiO₂ nanospheres. The hydrophilic PVDF porous membrane with a 450-nm inner pore size was chosen as the supporting structure. Pristine SiO₂ with a uniform particle size of 95–110 nm was synthesized and functionalized with –NH₂ and –COOH, respectively. Through-plane channels of porous membrane and arranged functional nanoparticles in pores could contribute to constituting efficient proton transfer channels. The characteristics such as morphology, thermal stability, water uptake, dimensional swelling, proton conductivity and methanol permeability as proton exchange membranes, of the SiO₂ nanospheres, and the composite membrane were investigated. The formation of ionic channels in membrane enhanced the water uptakes and proton conduction abilities of the composite membranes. PVDF/Nafion/SiO₂–NH₂ exhibited superior proton conductivities (0.21 S cm^?1) over other samples due to several proton sites and the acid–base pairs formed between –NH₂ and –SO₃H. Furthermore, all the composite membranes exhibited improved methanol resistance compared with Nafion. Therefore, such a design based on porous membrane provided feasibility for high-performance proton exchange membrane in fuel cell applications.     

Influence of copper hexacyanoferrate film thickness on the electrochemical properties of self-assembled 3-mercaptopropyl gold electrode and application as a hydrazine sensor

A copper hexacyanoferrate film was obtained on a modified electrode prepared by self-assembly of 3-mercaptopropyltrimethoxysilane on a gold surface. The film thickness was controlled using a layer-by-layer technique to tune the electrocatalytic properties of the electrode. Two electrodes with different hexacyanoferrate film thicknesses were prepared via three immersions (AuS/CuHCF3) and six immersions (AuS/CuHCF6) of the film in the precursor solutions. Cyclic voltammetry data were obtained to determine the adequate film thickness. Scanning electron microscopy images showed a roughness increase due to the growth of the film thickness at the electrode surface. Electrochemical impedance spectroscopy showed distinct behavior for the two electrodes prepared; while diffusion and charge transfer processes can be observed in both electrodes, an additional capacitive process at intermediary frequencies was observed for the AuS/CuHCF6 electrode. The charge transfer resistance (R _ct) for the AuS/CuHCF3 electrode (19.6 Ω cm²) was lower than for AuS/CuHCF6 (27.9 Ω cm²) due to the hexacyanoferrate film thickness, since the charge transfer process demands the simultaneous diffusion of K⁺ into the surface. Cyclic voltammetry was used to evaluate the application of the AuS/CuHCF3 electrode as an electrochemical sensor, revealing a linear correlation for hydrazine concentrations.     

Effect of pore size/distribution in TiO2 films on agarose gel electrolyte-based dye-sensitized solar cells

This study develops a simple method to change the distribution of the pore size in a TiO₂ layer, using polyethylene glycol (PEG), while maintaining nearly the same surface area and porosity to clarify how large pores affect the performance of dye-sensitized solar cells (DSSCs). Specifically, a heating step at 100 °C for a specific duration is added prior to PEG removal and TiO₂ sintering at 400 °C. This process transforms the role of the PEG from a surfactant to a pore generator (porogen) and forms larger pores, depending on the loading and aggregation time for the PEG to gain larger pores. The effect of larger pores in TiO₂ films under 30 % PEG loading, on the performance of an agarose gel electrolyte-based DSSC, was further investigated using the ionic liquid, 1-allyl-3-ethylimidazolium iodide (AEII). The I–V characteristic and the electrochemical impedance spectroscopy analysis show that larger pores readily improve redox couple diffusion in a TiO₂ porous electrode and modify the interface between electrolyte and TiO₂. Using the optimized TiO₂ film with larger pores (30 % PEG loading, 100 °C/60 min), an efficiency of 7.43 % is achieved for the agarose gel electrolyte-based DSSC, which represents a 26.1 % improvement over TiO₂ without the addition of PEG.     

Efficient separation of nitrite from aqueous solutions by grafting metalloporphyrin on Fe3O4 nanoparticles

A new sorbent comprising 3-aminopropyltriethoxy-silane-coated magnetic nanoparticles functionalized with organic moieties containing the cobalt(III) porphyrin complex Co (TCPP) [TCPP: 4,4′,4″,4″′-(21H,23H-porphine-5,10,15,20-tetrayl)tetrakis (benzoic acid)], was prepared, for nitrite removal from drinking water. Fe₃O₄ nanoparticles were synthesized by co-precipitation of Fe²⁺ and Fe³⁺, then surface of the Fe₃O₄ nanoparticles was modified with APTES and Co (TCPP). The sorbent was characterized using FTIR, TGA, XRD, SEM and TEM analysis. The batch experiments showed that the proposed sorbent can effectively be used to remove nitrite from water. Various parameters such as pH of the solution, contact time, sorbent dosage, concentration of desorbing reagent, and influence of other interfering anions have been investigated. Under optimal conditions for a nitrite concentration of 10 mg L^?1 (i.e., contact time 15 min, pH 5.5 and nanosorbents dosage 100 mg), the percentage of the extracted nitrite ions was 92.0. Nitrite sorbing material was regenerated with 10 mM NaOH up to 97.0 %. The regeneration studies also showed that nanosorbents are regenerable and can be used for a couple of times.     

A novel potential-triggered SBA-15/PANI/PSS composite film for selective removal of lead ions from wastewater

In this study, a novel potential-triggered electroactive composite film consisting of mesoporous silica SBA-15, polyaniline (PANI), and polystyrenesulfonate (PSS) was fabricated in an aqueous electrolyte solution via a facile pulse potentiostatic method. The obtained composite film was characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric (TG) analysis, and scanning electron microscopy (SEM). The ion exchange properties were evaluated in a solution containing 0.1 M Pb(NO₃)₂ by using an electrochemical quartz crystal microbalance (EQCM) as well as cyclic voltammetry (CV) method. It was found that the uptake/release of Pb²⁺ ions in/from SBA-15/PANI/PSS composite film was successfully achieved by modulating the redox states of the electroactive composite film, and the composite film exhibited different ion exchange behaviors at different scan rates. Based on these results, the ion exchange mechanism was proposed. Compared with the PANI/PSS composite film, the SBA-15/PANI/PSS composite film had higher adsorption capacity as well as higher selectivity toward Pb²⁺ ions, which should be attributed to the 3D porous morphology of the composite film with more active sites in the mesoporous SBA-15. Remarkably, the film maintained a high stability over 97% even after 500 successive cycles. It is expected that this SBA-15/PANI/PSS composite film can serve as a promising electroactive material for the effective separation of Pb²⁺ ions from wastewater.

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Graphical abstract ?

     

用于锂离子电池正极材料的分级孔碳/2,5-二巯基-1,3,4-噻二唑/聚噻吩三元复合物

采用酚醛树脂为碳源, 纳米碳酸钙为二次成孔剂, 通过煅烧、刻蚀、KOH活化等工艺制备出活化分级孔碳(aHPC). 在此基础上, 以aHPC为模板, 通过溶液浸渍制得活化分级孔碳/2,5-二巯基-1,3,4-噻二唑(aHPC/DMcT)复合物, 然后运用氧化聚合法将聚(3,4-乙烯二氧噻吩)—聚苯乙烯磺酸(PEDOT-PSS)包覆在其表面制备出aHPC/DMcT/PEDOT-PSS复合物. 并运用傅里叶变换红外(FTIR)光谱、X射线衍射(XRD)、场发射扫描电镜(FESEM)、透射电镜(TEM)和电化学测试等手段对所得复合材料的结构、形貌及电化学性能进行表征. 结果显示, KOH活化后, aHPC孔道内的官能基团含量增加了, 使得DMcT的负载量增大(52%), 且DMcT几乎全部进入到aHPC孔道内. aHPC/DMcT复合物的首次放电容量为236 mAh·g^-1, 循环20次后放电比容量仅为65mAh·g^-1. 而aHPC/DMcT/PEDOT-PSS复合物的表面包覆一层PEDOT-PSS导电薄膜, 其首次放电容量高达281 mAh·g^-1, 20次后的放电比容量为138 mAh·g^-1,容量保持率达49.1%.     

Synthesis and properties of the cationic fluorocarbon emulsifier-free latex in a new micellar system

Cationic fluorocarbon emulsifier-free latex (CFEL) based on hexafluorobutyl methacrylate (FA), styrene, butyl acrylate, and methacrylatoethyl trimethyl ammonium chloride is successfully prepared in a new micellar system in which the fluorinated surface active monomer (FSM) based on isophorone diisocyanate, dodecafluoroheptanol, and allyl polyethylene glycol is used. The chemical structure of FSM is characterized by Fourier transform infrared spectroscopy, ¹H-NMR, and its surface-active properties have been investigated by surface tension determinator. Besides, effect of FSM, FA, and also the curing temperature on the latex and film properties has been investigated by the coagulation ratio (W _c ), precipitation ratio (W _p ), Nano-ZS particle sizer, contact angle, and water absorption ratio, respectively. The results show that the FSM is successfully prepared. The CMC of FSM is 2.37 g L^?1 and the γ _CMC is 26.31mN m^?1 accordingly. The more FSM content makes more stable emulsion and have only little adverse effect on its film properties. When the FSM content increases from 1.05 to 13.11 %, the W _c and W _p decrease by 83.5 and 32.1 %, respectively, and the surface free energy (γ) of CFEL film only increases by 8.3 %. The more FA content makes less stable emulsion but have favorable effect on its film properties. When the FA content increases from 0 to 25.11 %, the γ is decreased by 55.1 %. The curing temperature has much impact on film property. For example, the γ from 27.47 to 20.36 mJ?·?m^?2 when the curing temperature rises from 30 to 110 °C.     

Forming Lipid Bilayer Membrane Arrays on Micropatterned Polyelectrolyte Film Surfaces

A novel method of forming lipid bilayer membrane arrays on micropatterned polyelectrolyte film surfaces is introduced. Polyelectrolyte films were fabricated by the layer‐by‐layer technique on a silicon oxide surface modified with a 3‐aminopropyltriethoxysilane (APTES) monolayer. The surface pK_a value of the APTES monolayer was determined by cyclic voltammetry to be approximately 5.61, on the basis of which a pH value of 2.0 was chosen for layer‐by‐layer assembly. Micropatterned polyelectrolyte films were obtained by deep‐UV (254 nm) photolysis though a mask. Absorbed fluorescent latex beads were used to visualize the patterned surfaces. Lipid bilayer arrays were fabricated on the micropatterned surfaces by immersing the patterned substrates into a solution containing egg phosphatidylcholine vesicles. Fluorescence recovery after photobleaching studies yielded a lateral diffusion coefficient for probe molecules of 1.31±0.17 μm² s^?1 in the bilayer region, and migration of the lipid NBD PE in bilayer lipid membrane arrays was observed in an electric field.     

Properties and deactivation of the active sites of an MoZSM-5 catalyst for methane dehydroaromatization: Electron microscopic and EPR studies

The MoZSM-5 (4.0 wt % Mo) catalyst has been characterized by high-resolution transmission electron microscopy, EDXA, and EPR. Two types of molybdenum-containing particles are stabilized in the catalyst in the course of nonoxidative methane conversion at 750°C. These are 2-to 10-nm molybdenum carbide particles on the zeolite surface and clusters smaller than 1 nm in zeolite channels. According to EPR data, these clusters contain the oxidized molybdenum form Mo⁵⁺. The surface Mo₂C particles are deactivated at the early stages of the reaction because of graphite condensation on their surface. Methane is mainly activated on oxidized molybdenum clusters located in the open molecular pores of the zeolite. The catalyst is deactivated after the 420-min-long operation because of coke buildup on the zeolite surface and in the zeolite pores.     

Reason analysis for Graphite-Si/SiOx/C composite anode cycle fading and cycle improvement with PI binder

Designed Graphite-Si/SiO_x/C composite electrodes for rechargeable lithium-ion batteries are prepared with different binder of carboxymethyl cellulose-styrene butadiene rubber (CMC-SBR) and polyimide (PI). Electrode performance of composites highly depends on the selection of binder. The Si-based/graphite composite electrode containing PI binder shows very stable cycle stability with the retention higher than 95 % after 30 cycles; however, the capacity of composite electrode with CMC-SBR binder fades to less than 80 % after 20 cycles. The improvement mechanism of PI binder is characterized by SEM, EDS mapping, adhesive strength test, and electric performance test. The surface of anode film does not show crack after several cycles, and the SEI on the surface of Si/SiO_x/C particle is characterized. It is found that anode film peeing off strength matches well with the composite cycle stability. This result is further supported with cell disassembly result. We believe that improvement of anode film adhesion strength is an effective way to get stable long cycle life.     

Protic ionic liquid-based gel polymer electrolyte: structural and ion transport studies and its application in proton battery

Proton-conducting free standing gel polymer electrolyte (GPE) films containing protic ionic liquid, 1-butyl-3-methylimidazolium hydrogen sulphate, immobilized in blend of poly(vinylidenefluoride-co-hexafluoropropylene) and poly(vinylpyrrolidone) have been prepared by solution-cast technique. Films have been characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), differential scanning calorimetry (DSC), complex impedance spectroscopy, and cyclic voltammetry. Ionic conductivity of the semicrystalline and porous GPE films has been obtained as ~3.9?×?10^?3 S cm^?1 at room temperature. Protonic nature of conduction in the films has been established by performing cyclic voltammetry and complex impedance spectroscopy on the cells having both blocking (stainless steel) and both reversible electrodes (Zn + ZnSO₄.7H₂O). The electrochemical stability window of the films has been found as ~3.8 V. The highest conducting film has been used as a separator and proton conductor to fabricate a proton battery of configuration Zn + ZnSO₄.7H₂O |GPE film| PbO₂ + V₂O₅. The battery shows an open circuit voltage of ~1.62 V. Energy density of the cell has been obtained as 35.2 W h kg^?1 for low current drain. Rechargeability of the cell has been tested for ten cycles. The maximum discharge capacity of the cell has been obtained as ~2.50 mA h g^?1 during the first discharge cycle.     

Corrosion inhibition and adsorption behavior of imidazoline salt on N80 carbon steel in CO2-saturated solutions and its synergism with thiourea

The inhibition and adsorption behavior of 2-undecyl-1-sodium ethanoate-imidazoline salt (2M2) and thiourea (TU) on N80 mild steel in CO₂-saturated 3 wt.% NaCl solutions was studied at 25?°C, pH 4, and 1 bar CO₂ partial pressure using electrochemical methods. It was found that inhibition efficiency (η%) increased with increase in 2M2 concentration but decreased with increase in TU concentration with optimum η% value at 20 mg l^?1 TU. The data suggest that the compounds functioned via a mixed-inhibitor mechanism. The inhibition process is attributed to the formation of an adsorbed film of 2M2 and TU via the inhibitors polycentric adsorption sites on the metal surface which protects the metal against corrosion. A synergistic effect was observed between TU and 2M2. Potential of unpolarizability, E _u, was observed in the presence of 100 mg l^?1 TU which was shifted positively in the presence of 2M2–100 mg l^–1 TU blends, which suggests that the presence of 2M2 stabilized the adsorption of TU molecules on the surface of the metal. The adsorption characteristics of 2M2 were approximated by Langmuir adsorption isotherm.     

Conductivity enhancement of PEDOT:PSS film via sulfonic acid modification: application as transparent electrode for ITO-free polymer solar cells

3-Hydroxy-1-propanesulfonic acid(HPSA)was applied as a modification layer on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)film via spin-coating,resulting in a massive boost of the conductivity of PEDOT:PSS film,and thus the as-formed PEDOT:PSS/HPSA bilayer film was successfully used as a transparent electrode for ITO-free polymer solar cells(PSCs).Under the optimized concentration of HPSA(0.2 mol L~(-1)),the PEDOT:PSS/HPSA bilayer film has a conductivity of 1020 S cm~(-1),which is improved by about 1400 times of the pristine PEDOT:PSS film(0.7 S cm~(-1)).The sheet resistance of the PEDOT:PSS/HPSA bilayer film was 98Ωsq~(-1),and its transparency in the visible range was over 80%.Both parameters are comparable to those of ITO,enabling its suitability as the transparent electrode.According to atomic force microscopy(AFM),UV-Vis and Raman spectroscopic measurements,the conductivity enhancement was resulted from the removal of PSS moiety by methanol solvent and HPSA-induced segregation of insulating PSS chains along with the conformation transition of the conductive PEDOT chains within PEDOT:PSS.Upon applying PEDOT:PSS/HPSA bilayer film as the transparent electrode substituting ITO,the ITO-free polymer solar cells(PSCs)based on poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]:[6,6]-phenyl C71-butyric acid methyl ester(PC_(71)BM)(PCDTBT:PC_(71)BM)active layer exhibited a power conversion efficiency(PCE)of 5.52%,which is comparable to that of the traditional ITO-based devices.     

基于分子的六氰合铁酸钴纳米粒子：合成，表征及其电化学性质

采用直接混合法制得平均尺寸小于50 nm的六氰合铁酸钴纳米粒子，元素分析表明其计量学分子式为K_0.2Co_1.4[Fe(CN)₆]•xH₂O，红外光谱证明此物质是由铁磁性的Co^II_1.5[Fe^III(CN)₆]和反铁磁性的KCo^III[Fe^II(CN)₆]组成，并含有一定量的结晶水。用六氰合铁酸钴纳米粒子修饰的玻碳电极具有良好的稳定性和可逆的循环伏安行为，其电化学特征受溶液中配对阳离子种类和支持电解质浓度的影响。作为电极表面的媒介体，该薄膜对多巴胺的氧化还原具有电催化作用。     

Synthesis of strongly fluorescent carbon quantum dots modified with polyamidoamine and a triethoxysilane as quenchable fluorescent probes for mercury(II)

This article reports on the synthesis of water dispersible carbon quantum dots (CDs) by a one-step hydrothermal method using polyamidoamine (PAMAM) and (3-aminopropyl)triethoxysilane (APTES) as a platform and passivant. The resulting CDs are highly uniform and finely dispersed. The synergistic effect between PAMAM and APTES on the surface of the CDs results in a fluorescence that is much brighter than that of CDs modified with either APTES or PAMAM only. The fluorescence of the co-modified CDs is quenched by Hg(II) ions at fairly low concentrations. Under the optimum conditions, the intensity of quenched fluorescence drops with Hg(II) concentration in the range from 0.2 nM to 10 μM, and the detection limit is 87 fM. The effect of potentially interfering cations on the fluorescence revealed a high selectivity for Hg²⁺. The fluorescent probe was applied to the determination of Hg(II) in (spiked) waters and milk and gave recoveries between 95.6 and 107 %, with relative standard deviation between 4.4 and 6.0 %.

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Graphical abstract Strongly fluorescent carbon quantum dots (CDs) modified with polyamidoamine (PAMAM) and 3-aminopropyltriethoxysilane (APTES) were synthesized by one-step hydrothermal strategy. The resulting co-modified CD s were used as fluorescent probe for sensitive and selective detection of Hg²⁺.

     

Solid-state electrochemiluminescence sensor based on the Nafion/poly(sodium 4-styrene sulfonate) composite film

An effective electrochemiluminescence (ECL) sensor based on Nafion/poly(sodium 4-styrene sulfonate) (PSS) composite film-modified ITO electrode was developed. The Nafion/PSS/Ru composite film was characterized by atomic force microscopy, UV-vis absorbance spectroscopy and electrochemical experiments. The Nafion/PSS composite film could effectively immobilize tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)₃²⁺) via ion-exchange and electrostatic interaction. The ECL behavior of Ru(bpy)₃²⁺ immobilized in Nafion/PSS composite film was investigated using tripropylamine (TPA) as an analyte. The detection limit (S/N = 3) for TPA at the Nafion/PSS/Ru composite-modified electrode was estimated to be 3.0 nM, which is 3 orders of magnitude lower than that obtained at the Nafion/Ru modified electrode. The Nafion/PSS/Ru composite film-modified indium tin oxide (ITO) electrode also exhibited good ECL stability. In addition, this kind of immobilization approach was simple, effective, and timesaving.