Parvia Yardani Sefidi - Department of Physical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz
Mig Ghasem Hosseini - Electrochemistry Research Laboratory, Department of Physical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, Iran

Photo electrochemical (PEC) water splitting is an efficient and ecofriendly technique forproducing hydrogen as clean energy source [1]. In this regard, researchers are focused on metaloxides and their nanocomposites as semiconductor materials for PEC cells [2]. In this research,camphor sulfonic acid doped polyaniline –WO3 (CSA PANI-WO3) and camphor sulfonic aciddoped polyaniline –WO3-MWCNT (CSA PANI-WO3-CNT) nanocomosites were synthesized viain situ oxidative polymerization and used as photoanodes in PEC cell under solar illumination.The synthesized nanocomposites were characterized with Fourier transform infrared (FTIR)spectroscopy, X-ray diffraction (XRD) and Field emission scanning electron microscopy(FESEM). The Photo electrochemical measurements were conducted with Origa Flex-OGA 01APotentiostate/Galvanostate using the thin films of CSA PANI-WO3 and CSA PANI-WO3-CNTon FTO conductive glasses as the photoanode, saturated calomel electrode (SCE) as thereference electrode and Pt plate as the counter electrode, respectively in 0.1 M Na2SO4 solution.The photo electrochemical tests were carried out in the dark and under illumination of Xenonlamp (300 W). The linear sweep voltammetry (LSV) was measured at -0.1- 1.6 V with 0.05 V/sscan rate. The electrochemical impedance spectroscopy (EIS) test was done in the frequencyrange of 100 kHz-100 mHz with AC amplitude of 10 mV. The Mott Schottky (M-S) analysiswas performed in the -0.8 – 0.8 V vs SCE at fixed frequency of 1 kHz. The photocurrent densityof CSA PANI-WO3-CNT (2.65 mA/cm2) is 1.42 times higher than CSA PANI-WO3 (1.87mA/cm2). The higher photocurrent density of CSA PANI-WO3-CNT is due to the increase of theseparation efficiency of electron-hole pairs and better electron transfer owing to MWCNT. Thepositive value of the slope of the M-S curves confirm the n-type semiconducting behavior ofboth nanocomposites having electrons as the majority carriers. Also, the charge transferresistance (Rct) of CSA PANI-WO3-CNT is 1499 Ωcm2 which is lower than CSA PANI-WO3(5375 Ωcm2) indicating the improvement of photoelectrocatalytic performance in the presence ofMWCNT.

Polyaniline, WO3 Nanoparticles, Solar Energy, Photo Electrochemical Water Splitting