Electrochemical preparation of hematite nanostructured films for solar hydrogen production

Abstract

Abstract. Photoelectrochemical water splitting is a clean and promising technique for using a renewable source of energy, i.e., solar energy, to produce hydrogen. In this work electrochemical formation of iron oxyhydroxide and its conversion to hematite (α-Fe 2 O 3 ) through thermal treatment have been studied. Oxyhydroxide iron compounds have been prepared onto SnO 2 /F covered glass substrate by potential cycling with two different potential sweep rate values; then calcined at 520 o C in air to obtain α -Fe 2 O 3 nanostrutured films for their implementation as photoanode in a photoelectrochemical cell. X-ray diffraction analysis allowed finding that iron oxides films have nanocrystalline character. Scanning electron microscopy revealed that films have nanostructured morphology. The obtained results are discussed considering the influence of potential sweep rate employed during the preparation of iron oxyhydroxide film on optical, structural and morphological properties of hematite nanostructured films. Results show that films have acceptable characteristics as photoanode in a photoelectrochemical cell for hydrogen generation from water.

Effect of morphology and impact of the electrode/electrolyte interface on the PEC response of Fe2O3 based systems – comparison of two preparation techniques

“…1,6 The major challenge associated with hematite in PEC system is high rate of electronhole pair recombination, poor diffusion length of minority charge carriers (2-4 nm), low depth of solar light penetration (a À1 ¼ 118 nm at l ¼ 550 nm) and slow kinetics of oxygen evolution reaction. [7][8][9][10] All these factors lead to reduced solar to chemical conversion efficiency and poor PEC performance of a-Fe 2 O 3 .…”

“…Fabrication of hematite thin lms has been done in the past by variety of procedures viz. hydrothermal method, [20][21][22][23] chemical vapor deposition, 7,8 sputtering, 24 electrochemical deposition, 9,25 spray pyrolysis, 13,26 etc. and it was seen that the response of the material denitely depends on its method of preparation.…”

Recovering Indium Tin Oxide Electrodes for the Fabrication of Hematite Photoelectrodes

“…[29][30][31][32] Electrodeposition of semiconductors has shown to be a simple, inexpensive and safe technique which is able to produce large area depositions with good substrate/thin film adherence. 19,33,34 Although, thin hematite films can be deposited through an easy and cheap method, 32,33,35,36 the high costs of the TCOs represent a drawback for the construction and scalability of PEC cells. Thus, recycled ITO might be an alternative substrate option to build low-cost PEC cells.…”