Large-area network of polyaniline nanowires supported platinum nanocatalysts for methanol oxidation

Abstract Nanocomposites comprised of Pt nanoparticles and electrically conducting polymers were prepared and tested for the electrocatalytic performance towards oxidation of methanol. Films of polyaniline (PANI) synthesized independently by potentiostatic and galvanostatic method, PANI(V) and PANI(I), respectively, were used as the supporting matrix for loading Pt nanoparticles. PANI(V), PANI(I), PANI(V)/Pt, and PANI(I)/Pt films were characterized for structure and morphology using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). SEM image of PANI(I) reveals that the particles are highly porous and interconnected nanowires, whilst PANI(V) particles are granular. The large surface area in the nanofibrillar PANI(I) makes the dispersion of Pt particle with a lesser time for the deposition of Pt particles. The porous network structure of PANI(I) helps in effective dispersion of Pt particles (about 10–20 nm) and facilitates easy access of methanol to the catalytic sites. The electrocatalytic activity of PANI(I)/Pt is much higher (current density (24.7 mA/cm 2  mg) at 0.68 V) in comparison to PANI(V)/Pt and bulk Pt electrodes (the current density values of 5.5 and 7.5 mA/cm 2  mg).

[1]  H. Kim,et al.  Performance and impedance under various catalyst layer thicknesses in DMFC , 2004 .

[2]  Vinay Gupta,et al.  Large-area network of polyaniline nanowires prepared by potentiostatic deposition process , 2005 .

[3]  Yen Wei,et al.  Polyaniline micro/nanofibers doped with saturation fatty acids , 2006 .

[4]  L. Niu,et al.  Formation optimization of platinum-modified polyaniline films for the electrocatalytic oxidation of methanol , 2003 .

[5]  Yingke Zhou,et al.  Preparation and Electrochemistry of SWNT/PANI Composite Films for Electrochemical Capacitors , 2004 .

[6]  V. S. Bagotzky,et al.  Electrocatalytic and adsorption properties of platinum microparticles electrodeposited into polyaniline films , 2001 .

[7]  J. Joo,et al.  Synthesis and Characterization of Polythiophene and Poly (3-methylthiophene) Nanotubes and Nanowires , 2005 .

[8]  Jing Li,et al.  Electrical and magnetic properties of the composite pellets containing DBSA-doped polyaniline and Fe nanoparticles , 2006 .

[9]  S. M. Yang,et al.  Synthesis of polyaniline nanotubes in the channels of anodic alumina membrane , 2005 .

[10]  T. Wen,et al.  Electrochemical Synthesis of a Polyaniline-Based Conducting Copolymer with —S—S—Links , 2001 .

[11]  D. Hatchett,et al.  Chemical and electrochemical synthesis of polyaniline/platinum composites , 2006 .

[12]  N. Miura,et al.  Potentiodynamically deposited nanostructured manganese dioxide as electrode material for electrochemical redox supercapacitors , 2004 .

[13]  M. Marandi,et al.  Electrochemical properties of the polypyrrole films doped with benzenesulfonate , 2007 .

[14]  T. Wen,et al.  Electrochemical and Spectroelectrochemical Studies on Copolymerization of Diphenylamine with 2,5-Diaminobenzenesulfonic Acid , 2002 .

[15]  R. Ortíz,et al.  Electrodeposition of silver on a poly(o-aminophenol) modified platinum electrode , 2001 .

[16]  K. Okajima,et al.  Optimization of the sputter-deposited platinum cathode for a direct methanol fuel cell , 2005 .

[17]  Y. Park,et al.  Studies on the anode catalysts of carbon nanotube for DMFC , 2004 .

[18]  A. Ohta,et al.  Influences of Both Carbon Supports and Heat‐Treatment of Supported Catalyst on Electrochemical Oxidation of Methanol , 1995 .

[19]  Shimshon Gottesfeld,et al.  Direct methanol fuel cells: progress in cell performance and cathode research , 2002 .

[20]  Zhongai Hu,et al.  The electrochemical synthesis of polyaniline/polysulfone composite films and electrocatalytic activity for ascorbic acid oxidation , 2006 .

[21]  Lintao Cai,et al.  Preparation and electroactivity of polyaniline/poly(acrylic acid) film electrodes modified by platinum microparticles , 1998 .

[22]  Li Li,et al.  Methanol electrooxidation on Pt particles dispersed into PANI/SWNT composite films , 2006 .

[23]  T. Wen,et al.  An in situ spectroelectrochemical investigation of the copolymerization of diaminobenzenesulfonic acid with aniline and its derivatives , 2001 .

[24]  A. Kitani,et al.  Electrocatalytic oxidation of methanol on platinum modified polyaniline electrodes , 2001 .

[25]  K. Jackowska,et al.  Reticulated vitreous carbon–polyaniline–palladium composite electrodes , 2005 .

[26]  Richard B Kaner,et al.  A general chemical route to polyaniline nanofibers. , 2004, Journal of the American Chemical Society.

[27]  C. Sivakumar.  Finely dispersed Pt nanoparticles in conducting poly(o-anisidine) nanofibrillar matrix as electrocatalytic material , 2007 .

[28]  In-Hwan Oh,et al.  The effect of pretreatment methods on the performance of passive DMFCs , 2004 .

[29]  S. Mallakpour,et al.  Morphological investigations of polypyrrole coatings on stainless steel , 2006 .

[30]  T. Wen,et al.  Enhanced electrocatalytic performance for methanol oxidation of a novel Pt-dispersed poly(3,4-ethylenedioxythiophene)–poly(styrene sulfonic acid) electrode , 2006 .

[31]  A. Gopalan,et al.  Platinum particles dispersed poly(diphenylamine) modified electrode for methanol oxidation , 2006 .

[32]  Vinay Gupta,et al.  Electrochemically Deposited Polyaniline Nanowire’s Network A High-Performance Electrode Material for Redox Supercapacitor , 2005 .

[33]  Yongsheng Chen,et al.  Remarkable support effect of SWNTs in Pt catalyst for methanol electrooxidation , 2005 .

[34]  B. Viswanathan,et al.  Nanostructured Conducting Polyaniline Tubules as Catalyst Support for Pt Particles for Possible Fuel Cell Applications , 2004 .

[35]  C. R. Martin,et al.  Effect of reagent concentrations used to synthesize polypyrrole on the chemical characteristics and optical and electronic properties of the resulting polymer , 1992 .