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

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.