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

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.