Investigation of solar-induced photoelectrochemical water splitting and photocatalytic dye removal activities of camphor sulfonic acid C doped polyaniline -WO3- MWCNT ternary nanocomposite

The camphor sulfonic acid doped polyaniline-WO3-multiwall carbon nanotube (CSA PANI-WO3-CNT) ternary nanocomposite was synthesized during in-situ oxidative polymerization and characterized by Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), and Energy-dispersive X-ray spectroscopy (EDS). The application of CSA PANI-WO3-CNT ternary nanocomposite was investigated as the photocatalyst in the degradation of methylene blue dye (MB) and as the noble metal-free photoanode in photoelectrochemical water splitting under solar light irradiation. The degradation percentage of MB dye after 60 min illumination by CSAPANI-WO3-CNT ternary nanocomposite reached 91.40% which was higher than that of pure WO3 (43.45%), pure CSA PANI (48.4%) and CSA PANI-WO3 binary nanocomposite (85.15%). The photocurrent density of indium tin oxide (ITO)/CSA PANI-WO3 -CNT photoanode obtained 0.81 mA/cm(2) at 1.23 V vs. reversible hydrogen electrode under illumination which was 1.27, 2.13, and 4.26 times higher than that of the ITO/CSA PANI-WO3 (0.64 mA/cm(2)), ITO/pure CSA PANI (0.38 mA/cm(2)), and ITO/pure WO3 (0.19 mA/cm(2)). Also, the applied bias photon-to-current efficiency (ABPE) of ITO/CSA PANI-WO3-CNT was obtained 0.11% which showed two-fold, four-fold, and five-fold enhancements compared to the ITO/CSA PANI-WO3, ITO/CSA PANI, and ITO/WO3, respectively. The electrochemical impedance spectroscopy, as well as the Mott-Schottky results, confirmed the better photoelectrocatalytic activity of ITO/CSA PANI-WO3-CNT in comparison with ITO/WO3, ITO/CSA PANI, and ITO/CSA PANI-WO3. The observed improvement in the photocatalytic and photoelectrocatalytic performances of WO3 in the presence of CSA PANI is due to the formation of type -II heterojunction between WO3 and CSA PANI which allows the separation of charge carriers easier and faster. On the other hand, MWCNT addition to the CSA PANI-WO3 nanocomposite provided the conducting substrate for efficient interfacial charge separation as well as transferring. (C) 2019 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.