Effect of plasmonic au nanoparticles on the photoactivity of polyaniline/indium tin oxide electrodes for water splitting

Abstract

Three nanomaterials based on polyaniline (PANI) are prepared on indium tin oxide (ITO) and applied as electrodes for H2 generation due to the water‐splitting process. PANI/ITO films are prepared using oxidation polymerization method at 25°C, then coated with Au nanoparticles with different thicknesses (sputter time from 1 to 2 min). The three prepared electrodes; PANI/ITO (Electrode (0), 1‐min‐Au/PANI/ITO (Electrode (I)), and 2‐min‐Au/PANI/ITO (Electrode (II)) are compared for H2 generation from H2O. Scanning electron microscope, X‐ray diffraction, UV‐Vis spectrophotometer, and Fourier‐transform infrared spectroscopy analyses have been carried out, in which the average PANI crystal size was ~20 nm. Moreover, the bandgaps were determined, in which 2‐min‐Au/PANI/ITO has the optimum bandgap of 2.25 eV. The characteristic behavior of the H2 generation took place depending on the current density (Jph) value by using Jph–V and Jph–time study. Also, the incident photon‐to‐current conversion efficiency (IPCE) and the applied bias photon‐to‐current efficiency (ABPE) were calculated for the Electrode (II) at 25°C. The optimum IPCE and ABPE efficiency were 18.7 and 0.99%, respectively, at 390 nm. By increasing the temperature to 70°C, the IPCE efficiency increases to about 37%. Finally, activation energy (Ea), enthalpy (ΔH*), and entropy (ΔS*) were determined, in which the values were 24.32 kJ mol−1, 10.90 kJ mol−1, and 74.99 J K−1 mol−1, respectively. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019