Fabrication of Tiron‐doped polypyrrole/MWCNT composite electrodes with high mass loading and enhanced performance for supercapacitors

In this study, the aromatic sulfonate compound Tiron with high charge to mass ratio is used as an anionic dopant for synthesis of polypyrrole (PPy). The fabricated PPy is investigated for electrochemical supercapacitor (ES) application. Testing results show that Tiron allows reduced PPy agglomeration, smaller particle size and improved charge storage properties of PPy. High capacitance and improved capacitive retention at high scan rates are achieved by the fabrication of PPy/multiwalled carbon nanotube (MWCNT) composite electrode using safranin (SAF) as a co‐dispersant. The Tiron‐doped PPy electrode shows the highest capacitance of 7.8 F cm^?2 with a mass of 27 mg cm^?2. The Tiron‐doped PPy/MWCNT composite electrode shows good capacitance retention with a capacitance of 1.0 F cm^?2 at the scan rate of 100 mV s^?1. Symmetric supercapacitor cells are fabricated using PPy based active materials. An energy density of 0.36 mWh cm^?2 is achieved. The energy/power density and capacitance retention of the Tiron‐doped PPy/MWCNT ES is significantly improved in comparison with PPy‐based ES, prepared without Tiron or MWCNT. The Tiron‐doped PPy/MWCNT symmetric supercapacitor presents good cycling performance with 91.4% capacitance retention after 1000 charge–discharge cycles. The PPy/MWCNT composites, prepared using Tiron and SAF co‐dispersant, are promising electrodes for ES. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42376.     

Preparation and electrochemical properties of poly‐2,5‐dihydroxyaniline/activated carbon composite electrode in organic electrolyte

Poly‐2,5‐dimethoxyaniline coating has been fabricated on active carbon (AC) substrates by cyclic voltammetry (CV) in organic system. The resulted coating is hydrolyzed to produce poly‐2,5‐dihydroxyaniline (PDHA) to enhance the capacitance of the composite electrode. Scanning electron microscope, Fourier transform infrared spectroscopy, X‐ray diffraction, Raman spectra, CV, electrochemical impedance spectroscopy, and galvanostatic charge/discharge test are used to investigate the properties of these electrodes. In organic electrolyte, due to the introduced hydroquinone units, high value of capacitance up to 975 F g^?1 of the PDHA/AC has been obtained at a current density of 0.37 A g^?1 at a potential window of 0–1.5 V. An asymmetric capacitor has been assembled with the PDHA/AC positive and pure AC negative electrodes, which is able to obtain a specific energy as high as 178 Whkg^?1 in the potential range of 0–2.0 V at a current density of 0.93 A g^?1. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

New carbon nanotube–conducting polymer composite electrodes for drug delivery applications

A novel drug delivery system (DDS) based on a carbon nanotube (CNT)–poly(3,4‐ethylenedioxythiophene) (PEDOT) composite was constructed via a layering method. Single‐walled CNTs (SWNTs) were immobilized on a gold electrode using a layer‐by‐layer technique. In particular, cysteamine (Cys) was firstly bonded to the gold surface through the strong S? Au association and SWNTs were subsequently linked onto the Cys layer through condensation reaction of ? NH₂ and carboxyl groups by 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide/N‐hydroxysuccinimide coupling. X‐ray photoelectron spectroscopy and Raman spectroscopy demonstrate that this is a facile route for immobilizing CNTs on gold electrodes. Finally PEDOT was electropolymerized on the SWNT‐functionalized electrode to make a SWNT–PEDOT composite, and the modified electrode was applied as a DDS. Dexamethasone, as a model drug, was incorporated into PEDOT in the electropolymerization. Investigations of the electrochemical properties of SWNT–PEDOT demonstrate that SWNTs greatly improve the conductivity and increase the charge capacity of PEDOT. The composite exhibits a petal‐like surface structure, 20–30 nm thick and 100–200 nm wide. Compared to a DDS based on pure PEDOT synthesized under the same conditions, SWNT–PEDOT has the merits of higher drug release rate and larger release amount. The average mass release for every five voltammetry cycles increases from 1.4126 to 1.8864 mg cm^?2. Copyright © 2011 Society of Chemical Industry     

Binder‐free porous PEDOT electrodes for flexible supercapacitors

Conducting polymers are attractive for potential applications in flexible electronic industries because of their unique advantages. To simplify the process of electrode preparation, porous poly(3,4‐ethylenedioxythiophene) (PEDOT) film electrodes without binder and conductive additive were synthesized facilely for flexible supercapacitors via an in situ solution micro polymerization at the surface of a soft etched tunnel aluminum (ETA) template at room temperature. The template was directly used as the current collector of electrodes. The morphologies of the samples and the template were compared using scanning electron microscopy (SEM), and the polymer molecular structure and composition were analyzed with Fourier‐transform infrared (FTIR) spectroscopy. Symmetric supercapacitors were assembled with the PEDOT electrodes, Celgard 2300 separator, and 1.0 M LiPF₆/EC+DMC+EMC (1 : 1 : 1 in volume) electrolyte. The electrochemical performance was evaluated using different techniques like galvanostatic charging/discharging tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The results from different current densities and scanning rates show the supercapacitors have good rate performance. The specific capacitance, energy density, and coulombic efficiency of the PEDOT supercapacitor can reach 69.0 F g^?1 (or 103.0 F m^?2), 24.0 Wh kg^?1, and ～95% at a current density of 0.2 A g^?1, respectively. Furthermore, the PEDOT electrodes exhibit relatively good cycle performance, and the capacitance retention ratio is ～72% after 1500 cycles. The electrode process was discussed. The results are comparable to that of the reported PEDOT, which indicates the applicability of the novel simple method of solution microreaction at the surface of a soft metal template to directly prepare binder‐free flexible electrodes. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42549.     

The study of multiwalled carbon nanotube deposited with conducting polymer for supercapacitor

The performance of supercapacitors with multiwalled carbon nanotubes deposited with conducting polymer as activate materials was greatly enhanced in contrast with electric double-layer supercapacitor with carbon nanotubes due to the conducting polymer's faradaic effect. They are promising as the secondary power sources in electric vehicles propulsion. Polypyrrole and poly(3-methylthiophene) were uniformly deposited onto multiwalled carbon nanotubes in organic system by chemical methods. A carbon nanotubes-polypyrrole composite-carbon nanotubes-poly(3-methyl-thiophene) composite based supercapacitor prototype (CNTs-pPy-CNTs-pMeT SCP), a carbon nanotubes-carbon nanotubes-polypyrrole based hybrid SCP (CNTs-CNTs-pPy SCP), a carbon nanotubes-carbon nanotubes-poly(3-methylthiophene) based hybrid SCP (CNTs-CNTs-pMeT SCP) as well as a CNTs-CNTs corresponding SCP were assembled in 1 M LiClO₄ acetonitrile solution. Their voltammetry characteristics, galvanostatic discharge and AC. impedance spectra were carried out in two-electrode mode. Pseudocapacitance effects are found out from those SCPs with composite electrodes and their measured capacitances are 87, 45 and 72 F g⁻¹ for CNTs-pPy-CNTs-pMeT SCP, CNTs-CNTs-pMeT SCP and CNTs-CNTs-pPy SCP, respectively. They are much larger than that of 21 F g⁻¹ for the CNTs-CNTs corresponding SCP, which is a double-layer SCP. Their measured specific energy is 1.82, 0.88 and 1.33 W h kg⁻¹ for those SCPs with composite electrodes. They are also much higher than that of 0.58 W h kg⁻¹ for the CNTs-CNTs corresponding SCP.     

Polypyrrole-wrapped NiCo2S4 nanoneedles as an electrode material for supercapacitor applications

In this study, dicobalt tetrasulfide (NiCo₂S₄) nanoneedles were successfully synthesized by a two-step hydrothermal method on nickel foam. A layer of polypyrrole (PPy) was further wrapped on the surface of the NiCo₂S₄ nanoneedles by in-situ polymerization. The obtained NiCo₂S₄@PPy composite was investigated for supercapacitor applications, which exhibited a capacitance of 1842.8 F g^?1 at 1 A g^?1. An asymmetric supercapacitor device fabricated with an activated carbon negative electrode and NiCo₂S₄@PPy positive electrodes exhibited an energy density of 41.2 Wh kg^?1 at 402.2 W kg^?1 with a high charge–discharge cycling stability (92.8% after 5000 cycles). These results demonstrate that NiCo₂S₄@PPy electrodes have broad application prospects as energy storage electrode materials.     

LiClO4 doped cellulose acetate as biodegradable polymer electrolyte for supercapacitors

The possibility of producing a biodegradable polymer electrolyte based on cellulose acetate (CA) with varied concentration of LiClO₄ for use in supercapacitors has been investigated. The successful doping of the CA films has been analyzed by FTIR and DSC measurements of the LiClO₄ doped CA films. The ionic conductivity of the films increased with increase in salt content and the maximum ionic conductivity obtained for the solid polymer electrolyte at room temperature was 4.9 × 10^?3 Ω^?1 for CA with 16% LiClO₄. The biodegradation of the solid polymer electrolyte films have been tested by soil burial, degradation in activated sludge, and degradation in buffer medium methods. The extent of biodegradation in the films has been measured by AC Impedance spectroscopy and weight loss calculations. The study indicated sufficient biodegradability of the materials. A p/p polypyrrole supercapacitor has been fabricated and its electrochemical characteristics and performance have been studied. The supercapacitor showed a fairly good specific capacitance of 90 F g^?1 and a time constant of 1 s. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Ionic conductivity studies and dielectric studies of Poly(styrene sulphonic acid)/starch blend polymer electrolyte containing LiClO4

Proton and lithium-ion conducting biodegradable solid polymer electrolytes were prepared using blends of poly(styrene sulphonic acid) (PSSA) and starch for supercapacitor applications. The ionic conductivities have been calculated using the bulk impedance obtained through impedance spectroscopy with varying blend ratio and plasticizer. Glycerol as plasticizer improved the film formation property, while lithium perchlorate (LiClO₄) as dopant enhanced the conductivity. The maximum conductivity has been found to be 5.7?×?10^?3?Scm^?1 at room temperature for 80/20 (PSSA/starch) blend ratio. The dielectric studies showed relaxation peaks indicating proton and Li⁺ conduction in the plasticized polymer blend matrix and dielectric modulus also exhibited a long tail feature indicating good capacitance. Differential scanning calorimetry thermograms showed two peaks and decreased with varying blend ratio and plasticizer. A carbon?Ccarbon supercapacitor was fabricated using suitable electrolyte, and its electrochemical characteristics using cyclic voltammetry, AC impedance and galvanostatic charge?Cdischarge were studied. Supercapacitor showed a fairly good specific capacitance of 115?Fg^?1 at 10?mV s^?1.     

A new strategy for porous carbon synthesis: Starch hydrogel as a carbon source for Co3O4@C supercapacitor electrodes

A novel Co₃O₄@C composite with a three-dimensional (3D) interconnected network morphology was successfully fabricated by anchoring cobalt oxide nanocrystals onto porous carbon originating from starch hydrogels via freeze drying, precarbonization and thermal treatment in an aqueous system. Benefiting from unique structural features, the optimized electrode delivers an excellent capacitance of 1314.0 F g^?1 (1 A g^?1) and outstanding durability in terms of capacity preservation (93.5% over 10,000 cycles). In addition, an asymmetric supercapacitor consisting of DF-2 and active carbon exhibits an energy density of 149.1 Wh?kg^?1 at 800 W kg^?1 while maintaining great stability. The observed excellent performance is attributed to the unique 3D network, good conductivity and high surface-to-volumetric ratio of the carbon skeleton derived from the starch gel, which has wide scope for applications.     

Ionic conductivity and dielectric studies of acid doped cellulose acetate propionate solid electrolyte for supercapacitor

Phosphoric acid doped cellulose acetate propionate (CAP) consisting of poly(ethylene glycol) (PEG) as plasticizer was investigated. Ionic conductivities and dielectric studies were carried at different temperature with varying concentration of H₃PO₄ using AC impedance method. The highest conductivity was 8.1 × 10^?4 S cm^?1 at 343 K and a long tail was featured in dielectric studies indicating good capacitance nature of the electrolyte. Interactions between added constituents were observed in FTIR and differential scanning calorimetry studies. Thin and compact fabricated supercapacitor demonstrated specific capacitance of 64 F g^?1 using cyclic voltammetry. Furthermore, the supercapacitor properties like AC impedance and charge‐discharge were studied. Stability was up to 96% at 1000th cycle. POLYM. ENG. SCI., 56:196–203, 2016. © 2015 Society of Plastics Engineers     

A highly oriented poly(3,4‐ethylenedioxythiophene) film: Facile synthesis and application for supercapacitor

A single crystal poly(3,4‐ethylenedioxythiophene) (PEDOT) film with highly oriented arrangement has been fabricated from an aqueous solution by a novel unipolar pulse electropolymerization method. Film formation mechanism was proposed based on the in situ mass change during electropolymerization process measured by the electrochemical quartz crystal microbalance. The compositions, morphology and crystal structure of the fabricated films are characterized by Fourier transfer infrared spectroscopy, scanning electron microscopy, and X‐ray diffraction, respectively. It is found that the prepared PEDOT film on carbon nanotubes (CNTs)‐modified electrode with a spongy dendritic structure possesses outstanding electroactivity, high specific capacitances (239.1 F?g^?1, including the specific capacitances of CNTs which is 21.4 F?g^?1), and excellent cycling stability with 7.3% decay from its initial capacitance over 10,000 cycles. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43418.     

A binder‐free Ir0.4Ru0.6‐oxide/functionalized multi‐walled carbon nanotube electrode for possible applications in supercapacitors

An initial study on a simple and inexpensive method to form an Ir_0.4Ru_0.6‐oxide (MMO) coating onto high‐area plasma functionalized multi‐walled carbon nanotubes (f‐MWCNTs) at the bench‐scale for possible supercapacitor (SC) applications is presented. f‐MWCNT electrodes are prepared in a two‐step process combining the growth of MWCNTs directly onto a 316 stainless steel mesh by thermal‐chemical vapour deposition (t‐CVD), followed by the addition of oxygen‐containing functionalities to their surface by plasma functionalization. The plasma functionalization step is done to: (i) improve electrode wettability and (ii) improve capacitive properties through the addition of pseudocapacitive oxygen functionalities. A simple dip‐dry method is then employed to coat the f‐MWCNTs with the desired MMO coating (Ir_0.4Ru_0.6‐oxide) prepared initially in a liquid precursor mixture. f‐MWCNT electrodes are suspended and dipped into the precursor then heated in air to evaporate the solvent while building the oxide layer. The resulting MMO/f‐MWCNT electrode exhibits excellent stability in 4 mol/L KOH electrolyte, yielding larger specific capacitance values than those obtained on bare f‐MWCNT electrodes; at a charging/discharging current density of 0.5 mA cm^?2, the MMO/f‐MWCNT and f‐MWCNT electrodes achieve specific capacitances of 664 ± 7 and 190 ± 30 F g^?1 in a 3‐electrode cell, respectively. The MMO/f‐MWCNT electrodes show good rate capability performance up to 10 mA · cm^?2 and excellent stability.

     

Electropolymerization of a poly(3,4-ethylenedioxythiophene) and functionalized, multi-walled, carbon nanotubes counter electrode for dye-sensitized solar cells and characterization of its performance

Composite films of poly(3,4-ethylenedioxythiophene) and functionalized, multi-walled, carbon nanotubes (PEDOT–MWCNT) were fabricated by a simple oxidative electropolymerization method. These films were formed on fluorine-doped, tin oxide, glass substrates as counter electrodes (CEs) of platinum-free, dye-sensitized solar cells (DSSCs). The surface morphology, formation mechanism and electrochemical nature of PEDOT–MWCNT films were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), cyclic voltammetry (CV) and alternating current (AC) impedance spectroscopy. The SEM and AFM images showed that PEDOT–MWCNT films were more porous than PEDOT films. CV and AC impedance spectroscopy revealed that the PEDOT–MWCNT electrode had higher electrocatalytic activity for the I₃⁻/I⁻ redox reaction and a smaller charge transfer resistance than the PEDOT electrodes. The energy conversion efficiency of the DSSC with a PEDOT–MWCNT CE was 13.0% higher than with a PEDOT CE using the same conditions with a ruthenium sensitizer.     

Electrochemical behavior of a Nafion‐membrane‐based solid‐state supercapacitor with a graphene oxide—multiwalled carbon nanotube—polypyrrole nanocomposite

In this study, we sprayed a graphene oxide–multiwalled carbon nanotube (GM) suspension in isopropyl alcohol–water onto a Nafion membrane. The electrodeposition of polypyrrole (PPy) was carried out on Nafion to complete the fabrication of a solid‐state symmetric supercapacitor. Nafion 117 membranes are used as electrolyte separators in the preparation of supercapacitors. The characterization of the symmetric supercapacitor was done by X‐ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. The electrochemical properties of the symmetric solid‐state supercapacitor were investigated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy techniques in 1M lithium chloride. A specific capacitance of 90.4 mF/cm² (258.3 F/g¹) was obtained for the supercapacitor at a scan rate of 10 mV s^?1. Maximum energy and power densities of 10 W h/kg and 6031 W/kg were obtained for the fabricated supercapacitor. In such a symmetric configuration, the highly interconnection networks of GM–PPy provided good structure for the supercapacitor electrode, and the good interaction between PPy and GM provided fast electron‐ and charge‐transportation paths so that a high capacitance was achieved. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44926.     

Performance improvement of Nafion based solid state electrochemical supercapacitor

An electrochemical supercapacitor in all solid configuration using perfluorosulfonate ionomer as polymer electrolyte has been successfully realized. Electrodes of supercapacitor have been prepared using activated carbon material and Nafion ionomer. This latter had the double function of binder and electrolyte. Nafion 115 membrane has been used as electrolyte separator in the preparation of small scale supercapacitors. The capacitance performance of these devices is comparable or better than traditional systems, which use sulfuric acid as electrolyte. The electrochemical evaluation of studied supercapacitor has been carried out by cyclic voltammetry, dc charge/discharge measurements and electrochemical impedance spectroscopy. A capacitance of 90 F/g (referred to the weight of active carbon material in the electrode) has been obtained with carbon having surface area (SA) of about 1000 m²/g and, a capacitance of 130 F/g with activated carbon having SA of 1500 m²/g. These interesting results have been tentatively explained with an optimal configuration of electrodes and with the concomitant beneficial effects on the carbon pores of adsorbed water and Nafion distribution, which produce low distribute resistance in the carbon composite electrodes.     

Fabrication of indium tin oxides (ITO)-supported poly(3,4-ethylenedioxythiophene) electrodes coated with active IrO<Subscript>2</Subscript> layer for morphine electrooxidation

Novel indium tin oxides (ITO)/PEDOT/IrO₂ composite electrodes were fabricated by dipping IrO₂ colloids onto poly(3,4-ethylenedioxythiophene) (PEDOT)-coated ITO substrate for morphine electrooxidation. Scanning electron microscopy (SEM) image showed that the active IrO₂ layer was dispersed more uniformly at PEDOT intermediate layer than at bare ITO substrate. Voltammetric measurements indicated that the as-prepared IrO₂ colloids are very active for both the oxygen evolution reactions (OER) and for reversible valance transition between lower and higher oxides. ITO/PEDOT/IrO₂ electrodes perform enhanced electrochemical activity towards the oxidation of morphine, as compared with the un-modified ITO-based PEDOT electrodes (ITO/PEDOT) or the ITO electrodes directly coated with IrO₂ (ITO/IrO₂), suggesting that the composite electrode materials are one of the potential candidates for morphine detection.     

Supercapacitive properties of electrodeposited polypyrrole on acrylonitrile–butadiene rubber as a flexible current collector

Flexible sheets consisting of acrylonitrile–butadiene rubber (NBR) and vapor-grown carbon fiber (VGCF) are newly prepared varying the composition (VGCF 10–30 wt%) for use as a current collector of supercapacitor electrodes. The electrical conductivity of as-prepared VGCF/NBR current collector can be enhanced as the content of VGCF increases. The VGCF/NBR current collector is then electrodeposited with pyrrole using a potentiodynamic cyclic voltammetry to yield a polypyrrole (PPy)/VGCF/NBR composite electrode. Cyclic voltammetry result for the PPy/VGCF/NBR composites shows that the sample with 30 wt% VGCF achieves a maximum specific capacitance (125.8 F g^?1) at 5?mV?s^?1 and reaches a lower specific capacitance at higher scan rates. In addition, the flexibility of supercapacitor electrode of PPy can also be established with a comparable capacitance value by using the NBR-based current collector.     

Fabrication of PANI@Ti3C2Tx/PVA hydrogel composite as flexible supercapacitor electrode with good electrochemical performance

Developing a new strategy to effectively prevent the restacking of MXene nanosheets will have significant impacts on designing flexible supercapacitor electrodes. Herein, a novel Ti₃C₂T_x/polyvinyl alcohol (PVA) porous sponge with 3D interconnected structures is prepared by sol-gel and freeze-dried methods. This Ti₃C₂T_x/PVA porous sponge is used as the template of in-situ polyaniline (PANI) polymerization, and the fabricated PANI@Ti₃C₂T_x/PVA hydrogel composite is applied as flexible supercapacitors electrodes. 1D conductive polymer chains PVA could increase the interlayer spacing of Ti₃C₂T_x nanosheets, which is beneficial to expose more electrochemical active sites. The supercapacitor based on PANI@Ti₃C₂T_x/PVA hydrogel composite exhibits the coexistence of double-layer capacitance and pseudocapacitance behavior. This supercapacitor shows a maximum areal specific capacitance of 103.8 mF cm^?2 at 2 A m^?2, and it also exhibits a maximum energy density of 9.2 μWh·cm^?2 and an optimum power density of 800 μW cm^?2. The capacitance of this supercapacitor is almost not change under different bending angles. Moreover, 99% capacitance retention is achieved after 10 000 charge/discharge cycles of the supercapacitor. The synergistic effect between PANI and Ti₃C₂T_x/PVA composite may improve the number of reactive sites and provide efficient channels for ion diffusion/electron transport.     

Study on preparation and properties of PVA‐SA‐PHB‐AC composite carrier for microorganism immobilization

Polyvinyl alcohol(PVA) bead crosslinked with boric acid has been widely utilized as a microorganism immobilization carrier. However, it has some disadvantages such as drastic cell viability loss, small adsorption capacity and mass transfer limitation. To improve upon these drawbacks, a new method to prepare PVA composite pieces with the addition of activated carbon (AC) and poly‐3‐hydroxybutyrate(PHB) was explored through a combination of freezing/thawing and the boric acid method and by using Tween‐80 to improve the mass transfer performance of hydrophobic organics. m‐Cresol and pyrene were used as representative compounds with benzene ring structures to model hydrophilic and hydrophobic organics in order to test the performance of PVA pieces. The results showed that, compared with the boric acid method alone, a combination of freezing/thawing and the boric acid method led to a decrease in total organic carbon(TOC) loss from 0.315 g g^?1 to 0.033 g g^?1 and increased the oxygen uptake rate(OUR) of microorganisms from 0.03 mg L^?1·min^?1 to 0.22 mg L^?1 min^?1. The m‐cresol equilibrium adsorption amount of the PVA‐SA(sodium alginate)‐PHB‐AC piece was 2.80 times that of the PVA‐SA piece. The diffusion coefficient of pyrene in the PVA‐SA‐PHB‐AC piece increased from 0.53×10^?9 m² min^?1 to 2.30×10^?9 m² min^?1 with increasing concentrations of Tween‐80 from 1000 mg L^?1 to 5000 mg L^?1. The PVA‐SA‐PHB‐AC composite carrier demonstrated great scope for immobilizing microorganisms for practical wastewater bio‐treatment. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39837.     

Enhancement of electrodes modified by electrodeposited PEDOT‐nanowires with dispersed Pt nanoparticles for formic acid electro‐oxidation

Preparation of electrodes modified with poly(3,4‐ethylenedioxythiophene) nanowires, PEDOT‐nw, was optimized using nanoparticles of dispersed Pt, Pt‐np, to be tested for HCOOH electro‐oxidation. The PEDOT‐nw is electrosynthesized directly on the working electrode, using mesoporous silica as template, by cyclic voltammetry from a 0.01 mol L^?1 monomer + 0.1 mol L^?1 tetrabutylammonium hexafluorophosphate solution in acetonitrile, on the Pt|PEDOT|mesoporous silica template previously modified electrodes. Using SEM, the presence of PEDOT nanowires with 20 to 25 nm in diameter was verified. In addition, its p ‐doping response is about 500 times larger than that obtained on the bulk polymer, maintaining full reversibility of the process. The subsequent electrochemical insertion of Pt‐np and formation of Pt‐np with average diameter of about 20 nm, checked by TEM, demonstrated that the catalytic activity of this nanostructured electrode remarkably enhanced HCOOH electro‐oxidation. The obtained current is up to 2 orders of magnitude higher than previously reported in similar studies, using a much smaller amount of Pt and with a potential decrease greater than 100 mV. Thus, we have at our disposal a simple, inexpensive, and highly reproducible way to prepare in situ nanostructured electrodes using just electrochemical techniques, which can be useful on all the applications of these devices. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44723.