Enhanced photoelectrochemical water splitting efficiency of hematite (α-Fe2O3)-Based photoelectrode by the introduction of maghemite (γ-Fe2O3) nanoparticles

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2021-04, Vol.410, p.113179, Article 113179
• Main Authors: Tokubuchi, Tsuyoshi, Arbi, Ramis Imran, Zhenhua, Pan, Katayama, Kenji, Turak, Ayse, Sohn, Woon Yong
• Format: Article
• Language: English
• Subjects: Hematite; Maghemite; Phase junction; Photo-electrochemical cell; Splitting; Time-resolved spectroscopy; Water
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2021.113179

[Display omitted] •We designed a phase-junction configuration of α and γ-Fe2O3 by inserting maghemite (γ-Fe2O3) particles in between a hematite (α-Fe2O3) layer and FTO substrate.•We prepared the micelle templated γ-Fe2O3 nanoparticles to suppress the phase transition from γ-Fe2O3 to α-Fe2O3.•The photo-anode consisting of the phase-junction configuration of α and γ-Fe2O3 showed a drastic improvement of the current density.•We could demonstrate using a time-resolved spectroscopic method that the enhancement of the performance originated from the retardation of the recombination, resulting from the improvement of the charge separation efficiency. To enhance the photo-electrochemical performance of hematite photo-electrode, we designed a phase-junction configuration of α and γ-Fe2O3. By inserting maghemite (γ-Fe2O3) particles synthesized by reverse micelle deposition, which is for suppressing the phase transition from γ-Fe2O3 to α-Fe2O3, in between a hematite (α-Fe2O3) layer and fluorine-doped tin oxide (FTO) substrate, we could achieve a drastic improvement of the current density. We successfully confirmed using Raman spectroscopy that γ-Fe2O3 still remained after the annealing process performed at high temperature and the phase-junction configuration of α/γ-Fe2O3 was constructed. In addition, we could demonstrate using a time-resolved spectroscopic method and an electro-impedance spectroscopy measurement that the enhancement of the performance originated from the retardation of the recombination, resulting from the improvement of the charge separation efficiency.