Modification of polyaniline-WO3 as a noble metal-free photo electrocatalyst with (6, 6) - Phenyl-C61- butyric acid methyl ester for solar photoelectrochemical water splitting

Development of semiconductors with appropriate bandgap energies, strong light absorption, effectual charge carrier separation, and rapid transport of photogenerated electrons and holes as photoanode for photoelectrochemical (PEC) water oxidation has gained a lot of attention in the recent years. In our previous studies, the PEC performance of polyaniline-WO₃ (PANI-W) nanocomposite was confirmed as a high-performance organic-inorganic photoelectrocatalyst. In this research, we modified polyaniline-WO₃ photoelectrocatalyst with (6, 6)-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM) as an efficient fullerene derivative with high electron-accepting capability and excellent electron mobility for solar-induced water oxidation. The as-synthesized compounds were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The electrochemical measurements showed that the activity of PC₆₁BM modified polyaniline-WO₃ toward water electro-oxidation enhanced. A photocurrent density of 1.63 mAcm⁻² at 1.23 V vs. RHE achieved for PANI-W-PCBM indicating ~2.5-fold improvement compared to that of PANI-W. Furthermore, the charge transfer resistance (R_ct) of PANI-W-PCBM at electrode/electrolyte interface under light irradiation is 433 Ωcm² which is 5.64 times lower than that of PANI-W (2441 Ωcm²). The modification of PANI-W nanocomposite with PC₆₁BM suppressed the recombination of photogenerated electrons and holes and provided more active sites for oxygen evolution reaction due to the outstanding electrical conductivity, carrier mobility, and large surface area of PC₆₁BM. Therefore, modification of organic-inorganic nanocomposite with conjugated carbon-based materials increased the PEC water splitting activity.