Photoelectrochemical water oxidation of surface functionalized Zr-doped α-Fe₂O₃ photoanode

In the present work, the photoelectochemical (PEC) water oxidation property of the Zr-doped α-Fe₂O₃ (Zr-α-Fe₂O₃) nanostructure-based photoanode was improved by Co(OH)₂ surface fictionalization. The surface functionalized Zr-α-Fe₂O₃ photoanode exhibits an improved water oxidation capability with photocurrent density of 1.9 mAcm⁻² at 1.23 V vs. RHE while comparing with pure α-Fe₂O₃ (0.42 mAcm⁻²) and Zr-α-Fe₂O₃ (0.96 mAcm⁻²) photoanodes. Moreover, the Applied bias photon-to-current efficiency (ABPE) was calculated for all prepared photoanodes and it was found that Zr-α-Fe₂O₃/Co(OH)₂ photoanode showed a higher value (0.22%) than pure α-Fe₂O₃ (0.04%) and Zr-α-Fe₂O₃ (0.08%) photoanodes. In addition, the charge transfer resistance (R_ct) of Zr-α-Fe₂O₃/Co(OH)₂ photoanode is only 21.6 Ω/cm², which is lower than that of pure α-Fe₂O₃ (990 Ω/cm²) and Zr-α-Fe₂O₃ (32.8 Ω/cm²) photoanodes. The enhancement in the PEC water oxidation performance of the Zr-α-Fe₂O₃/Co(OH)₂ photoanode is attributed by improvement of charge transfer process by surface-attached Co-based co-catalyst and thus improved overall PEC water oxidation efficiency.