Aqueous Synthesis of Z-Scheme Photocatalyst Powders and Thin-Film Photoanodes from Earth Abundant Elements
Journal of Environmental Chemical Engineering 2018
Andris Šutka, Mārtiņš Vanags, Urmas Joost, Krisjanis Smits, Jurģis Ruža, Jānis Ločs, Jānis Kleperis, Tālis Juhna

Solid-state narrow band gap semiconductor heterostructures with a Z-scheme charge-transfer mechanism are the most promising photocatalytic systems for water splitting and environmental remediation under visible light. Herein, we construct all-solid Z-scheme photocatalytic systems from earth abundant elements (Ca and Fe) using an aqueous synthesis procedure. A novel Z-scheme two-component Fe2O3/Ca2Fe2O5 heterostructure is obtained in a straightforward manner by soaking various iron-containing nanoparticles (amorphous and crystalline) with Ca(NO3)2 and performing short (20 min) thermal treatments at 820 °C. The obtained powder materials show high photocatalytic performances for methylene blue dye degradation under visible light (45 mW/cm2), exhibiting a rate constant up to 0.015 min−1. The heterostructure exhibits a five-fold higher activity compared to that of pristine hematite. The experiments show that amorphous iron-containing substrate nanoparticles trigger the Fe2O3/Ca2Fe2O5 heterostructure formation. We extended our study to produce Fe2O3/Ca2Fe2O5 nanoheterostructure photoanodes via the electrochemical deposition of amorphous iron-containing sediment were used. The visible-light (15 mW/cm2) photocurrent increases from 183 μA/cm2 to 306 μA/cm2 after coupling hematite and Ca2Fe2O5. Notably, the powders and photoanodes exhibit distinct charge-transfer mechanisms evidenced by the different stabilities of the heterostructures under different working conditions.


Keywords
Z-scheme; Photocatalyst; Hematite; Photoanode; Photoelectrochemical properties
DOI
10.1016/j.jece.2018.04.003
Hyperlink
https://www.sciencedirect.com/science/article/pii/S2213343718301805

Šutka, A., Vanags, M., Joost, U., Smits, K., Ruža, J., Ločs, J., Kleperis, J., Juhna, T. Aqueous Synthesis of Z-Scheme Photocatalyst Powders and Thin-Film Photoanodes from Earth Abundant Elements. Journal of Environmental Chemical Engineering, 2018, Vol. 6, No. 2, pp.2606-2615. ISSN 2213-3437. Available from: doi:10.1016/j.jece.2018.04.003

Publication language
English (en)
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