Synthesis of TiO2/Al2O3 Double-Layer Inverse Opal by Thermal and Plasma-Assisted Atomic Layer Deposition for Photocatalytic Applications

Hamsasew Hankebo Lemago; Feras Shugaa Addin; Dániel Atilla Kárajz; Tamás Igricz; Bence Parditka; Zoltán Erdélyi; Dóra Hessz; Imre Miklós Szilágyi

doi:10.3390/nano13081314

Nanomaterials (Apr 2023)

Synthesis of TiO2/Al2O3 Double-Layer Inverse Opal by Thermal and Plasma-Assisted Atomic Layer Deposition for Photocatalytic Applications

Hamsasew Hankebo Lemago,
Feras Shugaa Addin,
Dániel Atilla Kárajz,
Tamás Igricz,
Bence Parditka,
Zoltán Erdélyi,
Dóra Hessz,
Imre Miklós Szilágyi

Affiliations

Hamsasew Hankebo Lemago: Department of Inorganic and Analytical Chemistry, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
Feras Shugaa Addin: Department of Inorganic and Analytical Chemistry, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
Dániel Atilla Kárajz: Department of Inorganic and Analytical Chemistry, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
Tamás Igricz: Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
Bence Parditka: Department of Solid-State Physics, Faculty of Sciences and Technology, University of Debrecen, H-4002 Debrecen, Hungary
Zoltán Erdélyi: Department of Solid-State Physics, Faculty of Sciences and Technology, University of Debrecen, H-4002 Debrecen, Hungary
Dóra Hessz: Department of Physical Chemistry and Materials Science, Faculty of Chemical and Bioengineering, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
Imre Miklós Szilágyi: Department of Inorganic and Analytical Chemistry, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary

DOI: https://doi.org/10.3390/nano13081314
Journal volume & issue: Vol. 13, no. 8
p. 1314

Abstract

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In comparison to conventional nano-infiltration approaches, the atomic layer deposition (ALD) technology exhibits greater potential in the fabrication of inverse opals (IOs) for photocatalysts. In this study, TiO2 IO and ultra-thin films of Al2O3 on IO were successfully deposited using thermal or plasma-assisted ALD and vertical layer deposition from a polystyrene (PS) opal template. SEM/EDX, XRD, Raman, TG/DTG/DTA-MS, PL spectroscopy, and UV Vis spectroscopy were used for the characterization of the nanocomposites. The results showed that the highly ordered opal crystal microstructure had a face-centered cubic (FCC) orientation. The proposed annealing temperature efficiently removed the template, leaving the anatase phase IO, which provided a small contraction in the spheres. In comparison to TiO2/Al2O3 plasma ALD, TiO2/Al2O3 thermal ALD has a better interfacial charge interaction of photoexcited electron–hole pairs in the valence band hole to restrain recombination, resulting in a broad spectrum with a peak in the green region. This was demonstrated by PL. Strong absorption bands were also found in the UV regions, including increased absorption due to slow photons and a narrow optical band gap in the visible region. The results from the photocatalytic activity of the samples show decolorization rates of 35.4%, 24.7%, and 14.8%, for TiO2, TiO2/Al2O3 thermal, and TiO2/Al2O3 plasma IO ALD samples, respectively. Our results showed that ultra-thin amorphous ALD-grown Al2O3 layers have considerable photocatalytic activity. The Al2O3 thin film grown by thermal ALD has a more ordered structure compared to the one prepared by plasma ALD, which explains its higher photocatalytic activity. The declined photocatalytic activity of the combined layers was observed due to the reduced electron tunneling effect resulting from the thinness of Al2O3.

Published in Nanomaterials

ISSN: 2079-4991 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Science: Chemistry
Website: https://www.mdpi.com/journal/nanomaterials

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