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

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 alpha-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 alpha-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 alpha-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 x 1021 cm(-3)) were found to be maximized for the same sample. In virtue of their superior photoelectrochemical performance, GNP modified alpha-Fe2O3 thin films have substantial potential for use in PEC water splitting reactions.