Preparation of alpha -Fe sub(2)O sub(3) films by electrodeposition and photodeposition of Co-Pi on them to enhance their photoelectrochemical properties

In this paper, alpha -Fe sub(2)O sub(3) photoanodes with different structures were prepared on indium-doped tin oxide (ITO) coated glass by calcination of electrodeposited alpha -Fe films. Morphologies of the films can be varied from the nanoparticle to sparse dendrites, and then to high-density dendrites as the deposition time is prolonged. Their morphology-dependent photoelectrochemical properties with and without coupling with the photodeposited Co-Pi were investigated through the photocurrent and the photoresponse. The alpha -Fe sub(2)O sub(3) film exposing a larger area of the bottom layer has a low photocurrent onset potential; after coupling with the Co-Pi co-catalyst, their onset potentials are shifted to the negative direction. The photocurrent of hematite films can be enhanced more than 40% for the particle type and 70% for the dendritic type regardless of low photocurrent values. This indicates that the photodeposited Co-Pi can effectively suppress the photogenerated electron-hole recombination on the surface of hematite, especially dendritic alpha -Fe sub(2)O sub(3).