Titanium-coated high-density Fe2O3 single crystal nanowire array for solar water splitting

Abstract

Fe2O3 holds promising n-type semiconductor material in the field of solar water splitting due to its excellent photocatalytic properties. However, the photoelectrochemical performance of Fe2O3 is limited by its inherent properties such as poor conductivity, and charge separation efficiency owing to its recombination rate. Therefore, researchers are more focused on nanostructuring, doping, and surface coating to overcome these issues of Fe2O3. In this study, we have investigated a low-cost way to fabricate a Ti coating layer on a high-density Fe2O3 single-crystal nanowire array for solar water splitting. Firstly, we have prepared a high-density single-crystal Fe2O3 nanowire array at lower temperatures by a new approach stress-induced atomic diffusion method. Thereafter, the prepared nanowire array was coated by Ti film using RF sputtering. The optimal film thickness of 13 nm titanium coatings layer into Fe2O3 single crystal nanowire array exhibited a high photocurrent density of 1.36 mA/cm2 at 1.23 V versus RHE and solar to hydrogen conversion efficiency (STH) of 1.67%, which could be resulting from adjusted optoelectronic properties of the nanowires.