ITO/Poly-3-Methylaniline/Au Electrode for Electrochemical Water Splitting and Dye Removal

Abstract

Application of aniline derivative semiconductor nanopolymer and its Au composite for H2 generation and dye removal were investigated. Electrochemical polymerization of poly-3-methylaniline (P3MA) on ITO glass was carried out for acid medium. Au nanoparticles with crystal sizes of 15 and 30 nm were sputter coated on the surface. Chemical structure of the polymer and its composite was characterized using FTIR, XRD, 1HNMR, SEM, and UV-Vis. All function groups were confirmed using FTIR analyses. XRD confirmed the formation of nanopolymer with a crystal size of ∼15 nm. SEM confirmed the formation of smooth lamellar surface feature with a <20 nm nanoporous structure. Porosity and particle sizes increases with Au coating, confirmed using the modeling Image J program. Optical analysis also demonstrated that the strength of P3MA absorption peaks increases with rising Au coating time, in which the bandgap values changed from 1.64 to 1.63 eV for 15 and 30 nm Au, respectively. The photoelectrode ITO/PMT/30 nm Au was applied for H2 generation and dye removal. The current density (J ph) values were −0.3 and −1.6 mA.cm−2 in the absence and presence of the Congo red dye, respectively. The incident photon-to-current conversion efficiency (IPCE%) for the electrode was 2.3 at 390 nm. The activation energy (E a ) was 31.49 KJ mol−1. The enthalpy (∆H * ) and entropy (∆S * ) values were 114.49 and 160.46 JK−1 mol−1, respectively. A simple mechanism for the H2 generation and dye removal is mentioned.