Electrodeposited Co-Pi Catalyst on α-Fe2O3 Photoanode for Water-Splitting Applications

Abstract

Optoelectronic properties of hematite (α-Fe₂O₃) as a photoanode and the required over-potential in photo-assisted water splitting has been improved by presence of Co-Pi on its surface. In order to increase the lifetime of the photogenerated holes and lower the applied bias, cobalt-phosphate (Co-Pi) on nanostructured α-Fe₂O₃ by electrodeposition was deposited. The nanostructure morphology of the α-Fe₂O₃ was confirmed by XRD and SEM. After depositing four different thicknesses of Co-Pi on α-Fe₂O₃, their photo-electrochemical (PEC) property was determined using linear sweep voltammetry (LSV) and chronoamperometry. The SEM and EDX results showed a complete coverage of Co-Pi on α-Fe₂O₃ and that the Co:P ratio was approximately 1:1.9 for the best produced catalyst. The highest performance of about 200 mV decrease in the onset potential was achieved for the 30-minutes electrodeposited sample. The Co-Pi/α-Fe₂O₃catalyst showed an enhancement of 100% of photocurrent compared to the bare α-Fe₂O₃.