Highly efficient photoelectrochemical water splitting from P-doped α-Fe₂O₃ nanorod/BiVO₄ heterojunction array

We report the fabrication of P-doped α-Fe₂O₃ nanorod/BiVO₄ heterojunction photoelectrode for photoelectrochemical (PEC) water splitting. The heterojunction photoelectrode is fabricated by combining methods of hydrothermal deposition, wet impregnation and metal organic decomposition. The structure and PEC activity of the photoelectrode are systemically studied. This heterojunction photoelectrode exhibits a surprising photocurrent density of 1.17 mA/cm² at 0.8 V vs. Ag/AgCl, which is approximately 3.55 times higher than that of the pristine α-Fe₂O₃. The photoconversion efficiency is 9.58 times higher than α-Fe₂O₃ and the onset potential has an obvious negative shift of 450 mV compared to the α-Fe₂O₃ for the heterojunction photoelectrode. The significant enhancement of PEC water splitting performance is attributed to the heterojunction structure and the synergistic effects of P-doping, which contributes to expediting electron and hole transfer and reducing carriers recombination. This novel design may provide an efficient way to developing efficient heterojunction photoelectrodes for practical PEC application.