The influence of temperature on the performance of a photoelectrochemical (PEC) cell prepared with Si-doped hematite photoanode was studied for water splitting. The cell performance was characterized by photocurrent-voltage (J-V) characteristic curves and electrochemical impedance spectroscopy at different cell operating temperatures, from 25 degrees C to 65 degrees C. A standard three-electrode configuration comprehending the photoelectrode of hematite, the counter-electrode of pure platinum wire (99.9%) and the reference electrode of Ag/AgCl/Sat.KCI was used. The identification of possible degradation pathways was addressed. It was observed that the generated photocurrent density increased with temperature. However, the photoelectrode became unstable above 50 degrees C. The experiments performed concerning the study of the temperature effect and the aging showed that the optimal operation temperature of the PEC cell is ca. 45 degrees C; this temperature ensures simultaneously the highest photocurrent density and stability. This study is important for understanding the behavior of hematite photoelectrodes operating under real outdoor conditions. (C) 2014 Elsevier B.V. All rights reserved.