Synergistic effects of P-doping and a MnO2 cocatalyst on Fe2O3 nanorod photoanodes for efficient solar water splitting

Abstract

Herein, we design and fabricate hematite (Fe₂O₃) nanorod photoanodes modified with P-doping and a MnO₂ oxygen evolution cocatalyst for photoelectrochemical (PEC) water splitting. This novel MnO₂/P:Fe₂O₃ photoanode exhibited a remarkably enhanced PEC water oxidation activity, and its photocurrent density is approximately 5-fold higher than that of pristine Fe₂O₃. The significant improvement of PEC performance is mainly attributed to the synergistic effects of P-doping and MnO₂ cocatalysts. More specifically, the Mott–Schottky and Nyquist plots clearly reveal that P-doping could not only effectively increase the density of charge carriers but also enhance the electron and hole transfer mobilities of Fe₂O₃ photoanodes. Furthermore, the MnO₂ cocatalyst modification can significantly facilitate charge separation and hole transport to the photoanode/electrolyte interface for water oxidation. Therefore, these demonstrations may provide an alternate strategy for designing and fabricating highly efficient Fe₂O₃-based PEC systems for solar energy conversion.