Electrochemical deposition of hematite and investigation of its photoelectrochemical properties for water splitting

Production of hydrogen using photoelectrochemical water splitting is a promising method for production of clean and renewable energy source. Using positive and negative semiconductors respectively as photocathode and photoanode, water can be splitted into hydrogen and oxygen. In this study, hematite was synthesized using electrochemical deposition. The diffraction pattern obtained using x-ray diffraction showed hematite having rhombohedral crystal structure. Surface morphology obtained by scanning electron microscope showed a two-layer structure, lower layer with cracks and upper layer consisting of particles. Photocurrent density was obtained using linear sweep voltammetry under chopped illumination and it was obtained at 0.6V vs Ag/AgCl as 2.5 μA.cm-2. Nyquist plot of hematite at potentials of 0V and 0.6V was obtained using electrochemical impedance spectroscopy and an equivalent circuit was fitted to EIS data and the value of the parameters was obtained. Also, using Mott-schottky plot, the flat band potential and the carrier density were obtained to be -0.35V vs Ag/AgCl and 8.4×1018 cm-3.