Preparation of α-Fe₂O₃ films by electrodeposition and photodeposition of Co–Pi on them to enhance their photoelectrochemical properties

Abstract

Photocurrents of different structures of α-Fe2O3 photoanodes, prepared by calcination of electrodeposited α-Fe films, are enhanced by Co–Pi co-catalyst.

Electrodeposited Ti-doped hematite photoanodes and their employment for photoelectrocatalytic hydrogen production in the presence of ethanol

“…This onset shifted to smaller values in the case of Ti-doped hematite and shifted a bit further in the presence of ethanol. These values were about 100-200 mV smaller than the onset reported for chemical vapor deposited hematite [5], comparable with the values reported in other electrochemically deposited hematite studies [6,7], but larger than the onset potential reported for Pt doped, electrochemically deposited hematite photoanodes [8]. The most impressive changes were, however, recorded with the photocurrent.…”

“…Thus, while for TiO 2 and WO 3 the hole diffusion length is $100 lm and 100-150 nm, respectively, in the case of hematite it is only 2-4 nm [6]. Furthermore, electron mobility in hematite is low (10 À1 V À1 s À1 ) [7] short [8]. For this reason, it is necessary to apply hematite on electrodes in the form of thin films, in order to allow charge carriers to reach the electrode.…”

“…A versatile synthesis procedure, allowing performance optimization by doping, has been obtained by the hydrothermal route [11][12][13][14]. An equally versatile, room temperature procedure for hematite film formation and doping is by electrodeposition [6][7][8]15,16]. The last procedure, which is easy to apply and interesting for industrial applications, has been adopted for the purposes of the present work.…”

“…Metal doping involves a variety of dopants, for example, Pt [8], Zn and Ti [16]. Another interesting approach is to combine hematite with an oxygen evolution co-catalyst, such as Co-Pi [7]. Electrodeposition is usually followed by high temperature annealing, which affects grain size and grain boundaries and, subsequently, overall photocatalyst performance [17].…”

Fivefold Enhanced Photoelectrochemical Properties of ZnO Nanowire Arrays Modified with C3N4 Quantum Dots

“…Compared with other semiconductors such as single elements and sulfides, metal oxides have been widely concerned and studied because of their low cost and high stability. Among them, zinc oxide (ZnO) due to the low initial potential and the ability to quickly transfer electrons to stimulate more people to study it [7][8][9], Lei et al synthesized ZnO quantum dots and was employed to enhance H 2 evolution for triazine imide and graphitic carbon nitride (g-C 3 N 4 ) [10]. Moreover, Kang et al demonstrated that coating nafion polymer films on the surface of ZnO thin photoanode exhibited photoelectric properties [11].…”