Carbon Modified (CM)- n-Fe2O3 Thin Films for Efficient Photoelectrochemical Splitting of Water

Abstract

Carbon modified n-type Iron (III) oxide (CM-n-Fe2O3) photoelectrodes were synthesized by thermal oxidation of Fe metal sheets (Alfa Co. 0.25 mm thick) by heating at several temperatures for different lengths of time. Reference n-Fe2O3 films were prepared by electric oven for comparison. The photocatalytic activity of both CM-n-Fe2O3 and oven made n- Fe2O3 was evaluated by measuring the rate of water splitting reaction to hydrogen and oxygen, which is proportional to photocurrent density, jp. The photoelectrodes were illuminated by light intensity of 100 mW cm-2 from a 150 Watt Xenon arc lamp. At a potential of 0.0 V (V/SCE) and under illumination intensity of 100 mW cm-2 the photocurrent density increased from 5.1 mA cm-2 for oven made n-Fe2O3 to 8.75 mA cm-2 for carbon modified n-type Iron (III) oxide (CM-n-Fe2O3) photoelectrodes synthesized by thermal oxidation. The corresponding maximum photoconversion efficiency improved significantly from 3.6 % for oven made n-Fe2O3 to 6.5% for CM- n-Fe2O3 synthesized by thermal oxidation process. Both n-Fe2O3 electrodes were characterized by using UV-Vis spectra, scanning electron microscope (SEM), monochromatic photocurrent density analysis, and energy dispersive analysis by X-ray (EDAX).