Anodic deposition of nanostructured hematite film using agarose gel as template. Application in water splitting

Abstract

The present study shows the results obtained in anodic electrodeposition of hematite precursor films in agarose gel template and photoelectrochemical characterization of the prepared hematite films. The peak current in cyclic voltammetry increases after each scan of the potential between −0.1 and 1.3 V for FTO electrode covered with a film of agarose gel in 0.1 M iron sulfate solution. The hematite samples with different thicknesses were prepared using template electrodeposition and annealing in air. The obtained nanostructured films were characterized by field emission scanning electron microscopy, X-ray diffraction, UV–vis spectroscopy, X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy. The results show that a synergistic improvement of photocurrent density (1.14 mAcm−2 at 1.23 V vs RHE) is induced by Sn-doping and slight surface modification of hematite with thin and discontinuous NiO film. The results indicate that thicker hematite films and hematite films strongly modified with NiO nanostructures show a reduced photoactivity.