Temperature effect on water splitting using a Si-doped hematite photoanode

Abstract

The influence of temperature on the performance of a photoelectrochemical (PEC) cell prepared with Sidoped hematite photoanode was studied for water splitting. The cell performance was characterized byphotocurrent-voltage (JeV) characteristic curves and electrochemical impedance spectroscopy atdifferent cell operating temperatures, from 25 C to 65 C. A standard three-electrode configurationcomprehending the photoelectrode of hematite, the counter-electrode of pure platinum wire (99.9%) andthe reference electrode of Ag/AgCl/Sat.KCl was used. The identification of possible degradation pathwayswas addressed. It was observed that the generated photocurrent density increased with temperature.However, the photoelectrode became unstable above 50 C. The experiments performed concerning thestudy of the temperature effect and the aging showed that the optimal operation temperature of the PECcell is ca. 45 C; this temperature ensures simultaneously the highest photocurrent density and stability.This study is important for understanding the behavior of hematite photoelectrodes operating under realoutdoor conditions.