Polyaniline Doped with Various Inorganic Acids and Polymeric Acids as Platinum Catalyst Support for Methanol Electro‐oxidation

Abstract

Polyaniline (PANI) is doped with H2SO4, HCl, poly(acrylic acid) (PAA), poly(acrylic acid‐co‐maleic acid) (PAMA), PAA+HCl, and poly(styrenesulfonic acid) (PSS) to obtain PANI‐H2SO4, PANI‐HCl, PANI‐PAA, PANI‐PAMA, PANI‐(PAA+HCl), and PANI‐PSS films, respectively. Ultraviolet‐visible (UV‐Vis) and Fourier transform infrared (FT‐IR) spectroscopy result confirm that PANI is doped with PSS. X‐ray photoelectron spectroscopy (XPS) results indicate that the nitrogen atoms of PANI‐PSS are the most positively charged in these films. Scanning electron microscopy (SEM) images reveal that these films are composed of highly porous nanowires. Platinum (Pt) can be incorporated into PANI‐H2SO4, PANI‐HCl, PANI‐PAA, PANI‐PAMA, PANI‐(PAA+HCl), and PANI‐PSS films via electrochemical deposition to obtain PANI‐H2SO4‐Pt, PANI‐HCl‐Pt, PANI‐PAA‐Pt, PANI‐PAMA‐Pt, PANI‐(PAA+HCl)‐Pt, and PANI‐PSS‐Pt composite electrodes, respectively. Auger electron spectroscopy (AES) results indicate that Pt particles disperse more uniformly into the spatial regions of PANI‐PSS and PANI‐(PAA+HCl) than those of other films. The PANI‐PSS‐Pt electrode provides the most active surface area of Pt in these electrodes. Cyclic voltammetry results and chronoamperometric response measurements show that the activity and stability toward methanol oxidation of the PANI‐PSS‐Pt electrode are the best in these electrodes.

Electrochemically-Obtained Polysulfonic-Acids Doped Polyaniline Films—A Comparative Study by Electrochemical, Microgravimetric and XPS Methods

“…The latter is based on data for the polymerization and redox charges and should be also an estimate for doping. PSSA-doped PANIs were studied by means of XPS in several cases [13][14][15][16] but information on their electrochemical behavior obtained with the same materials was not communicated. In some cases [13,16] PANI was obtained chemically but electrochemical studies were not in the focus of interest.…”

“…In some cases [13,16] PANI was obtained chemically but electrochemical studies were not in the focus of interest. In the remaining investigations [14,15] the polymerization was electrochemical but it was carried out in the presence of inorganic ions. In subsequent steps PANI was chemically transformed in the emeraldine base state and thereafter re-doped with PSSA.…”

“…Apart from simple inorganic anions (e.g., chloride, sulfate or perchlorate), several sulfonic acids such as camphorsulfonic, dodecylbenzene sulfonic, acrylamidomethylpropane sulfonic or p-toluene sulfonic were also explored with respect to the influence on PANI properties [ 4 , 5 , 6 , 7 , 8 , 9 ]. Furthermore, electrochemical and/or chemical synthesis of PANI was studied in the presence of polysulfonic acids, e.g., polystyrenesulfonic (PSSA) or poly(2-acrylamido-2-methyl-1-propanesulfonic) (PAMPSA) [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. In the recent years a series of papers [ 19 , 20 , 21 , 22 , 23 , 24 , 25 ] was devoted to the properties of PANI obtained in the presence of two poly(amidosulfonic acids) that are identical in their chemical composition but differ in the rigidity of their backbone-poly-(4,4′-(2,2′-disulfonic acid)-diphenylene-tere-phthalamide) (t-PASA, rigid backbone) and poly-(4,4′-(2,2′-disulfonic acid)-diphenylene-iso-phthalamide) (i-PASA, semi-rigid backbone) ( Scheme 1 ).…”

3D Polyaniline Architecture by Concurrent Inorganic and Organic Acid Doping for Superior and Robust High Rate Supercapacitor Performance

“…This indeed has been the motivation for the present work and the realization of the stated goal is amply demonstrated through careful optimization experiments on a scheme of binary (strong-inorganic + weak-organic) acid doping in the conducting polymer polyaniline. There are two previous reports by Kuo et al 33 34 on dual acid doping in polyaniline but in a different context, namely methanol oxidation with Pt nanoparticles loaded PANI as a catalyst material. They co-doped polyacrylic acid (PAA) and HCl which was shown to lead to effective dispersion of Pt nanoparticles in such polymer matrix as against only HCl doped PANI due to better morphology.…”

Recent Progress on Graphene/Polyaniline Composites for High-performance Supercapacitors

“…During polymerization of PANI, the acidic condition ensures the doping of PANI backbone skeleton, and also endows the electron conductivity of PANI. Therefore, the acid types have an important influence on the microstructure and electrochemical performance of PANI nanostructures [11,12,13]. Tabrizi et al [14] investigated the effect of the acid types including H 2 SO 4 , HCl, HClO 4 , and p -toluenesulfonic acid (PTSA) on the performance of PANI/GO composite.…”