Morphological, optical and photoelectrochemical properties of Fe2O3–GNP composite thin films

Abstract

The ever increasing demand for energy and increased environmental pollution has led to the search for new and renewable energy sources. Harnessing solar energy for the production of clean hydrogen is a very attractive method. This paper focuses on the synthesis of iron oxide photoanodes modified with graphene nanoplates (Fe₂O₃–GNP) as conducting scaffolds for the efficient generation of hydrogen in a photoelectrochemical (PEC) cell using solar energy. These GNP modified α-Fe₂O₃ samples were found to exhibit an enhanced photoresponse, which has been mainly attributed to: (i) efficient charge transfer at the semiconductor/electrolyte junction, and (ii) a red shift in the UV-vis spectra of the composite Fe₂O₃–GNP thin films with respect to the pristine α-Fe₂O₃ sample. The highest photocurrent density of 2.5 mA cm⁻² at 0.75 V/SCE was observed for the 0.2 wt% GNP modified α-Fe₂O₃ sample, with a solar to hydrogen conversion efficiency of 1.8%. The flat band potential (−0.83 V/SCE) and donor density (1.09 × 10²¹ cm⁻³) were found to be maximized for the same sample. In virtue of their superior photoelectrochemical performance, GNP modified α-Fe₂O₃ thin films have substantial potential for use in PEC water splitting reactions.