Synthesis and photoelectrochemical water oxidation of (Y, Cu) codoped α-Fe2O3 nanostructure photoanode

Abstract Hematite (α-Fe2O3) is one of the best capable photoanode material for water oxidation under visible light. The role of synergetic effect between two metal dopants for enhanced water oxidation is not adequately studied. The mono-doping (Y) and co-doping (Cu, Y) effect on the crystal structure, morphology, optical properties and their influence as photoanodes for energy harvesting applications are systematically explored. In this study, we have synthesized the pure, mono-doped (Y), and co-doped (Y and Cu) hematite nanostructures for enhanced photoelectrochemical (PEC) performance using a simple template free hydrothermal synthesis technique. The optimized photoelectrode showed a substantial improvement (∼36-times) in the PEC photocurrent density over pristine, mono-doped and co-doped photoanodes. Electrochemical impedance spectroscopy analysis confirmed that the co-dopant enhanced the charge carrier density of hematite and it acts as an electron donor. Moreover, it is demonstrated that the photocurrent density increases after mono-doping from 0.012 mAcm−2 to 0.020 mAcm−2 and further improved to 0.439 mAcm−2 with co-dopant at 1.23 V vs. RHE. The considerably enhanced PEC activity is ascribed to the higher conductivity, enhanced interfacial charge transfer at the surface of hematite and the synergistic effect between two metal dopants.