title: Fabrication of CaFe2O4/TaON heterojunction photoanode for photoelectrochemical water oxidation.
abstract: Tantalum oxynitride photoanode is fabricated and modified with calcium ferrite to form a heterojunction anode for a photoelectrochemical water splitting cell. The synthesized powders are loaded sequentially to the transparent conducting glass by electrophoretic deposition, which is advantageous to form a uniform layer and a junction structure. X-ray diffraction, UV-vis diffuse reflectance spectroscopy, scanning electron microscopy, and impedance spectroscopy analysis are conducted to investigate the structural, morphological, and electrochemical characteristics of the anode. The introduction of CaFe2O4 overlayer onto TaON electrode increases the photocurrent density about five times at 1.23 V vs reversible hydrogen electrode without any co-catalyst. Impedance spectroscopy analysis indicates that the junction formation increased photocurrent density by reducing the resistance to the transport of charge carriers and thereby enhancing the electron-hole separation. This photocurrent generation is a result of the overall water splitting as confirmed by evolution of hydrogen and oxygen in a stoichiometric ratio. From the study of different junction configurations, it is established that the intimate contact between TaON and CaFe2O4 is critical for enhanced performance of the heterojunction anode for photoelectrochemical water oxidation under simulated sun light.
authors: Department of Chemical Engineering, Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang 790-784, Republic of Korea.
authors: Eun Sun
authors: ES
authors: Kim
authors: Naoyuki
authors: N
authors: Nishimura
authors: Ganesan
authors: G
authors: Magesh
authors: Jae Young
authors: JY
authors: Kim
authors: Ji-Wook
authors: JW
authors: Jang
authors: Hwichan
authors: H
authors: Jun
authors: Jun
authors: J
authors: Kubota
authors: Kazunari
authors: K
authors: Domen
authors: Jae Sung
authors: JS
authors: Lee