Nonequilibrium Ti⁴⁺ Doping Significantly Enhances the Performance of Fe₂O₃ Photoanodes by Quenching

Hematite (α-Fe₂O₃) is one of the most promising photoanodes for solar water splitting due to its narrow band gap, high photostability and low cost. Though intensive studies have been done on α-Fe₂O₃ photoelectrodes in the past decades, the reported record efficiency is still much lower than the theoretical maximum value (about 16 %). High resistance is one of key challenges for high performance. In this work, we used a facile quenching method to realize nonequilibrium Ti⁴⁺ doping and decrease resistance of a Fe₂O₃ photoanode, which indicated much higher performance than that of a sample cooled naturally by conventional methods. To the best of our knowledge, this is the first demonstration of improving the performance of doped Fe₂O₃ by a quenching method. This method can serve as a reference for other doped photoelectrodes for solar water splitting.