Defect-Mediated Crystallization of the Particulate TiO2 Photocatalyst Grown by Atomic Layer Deposition

: Bhuskute, Bela D.; Ali-Löytty, Harri; Saari, Jesse; Hiltunen, Arto; Ruoko, Tero-Petri; Salminen, Turkka; Valden, Mika

Publisher: AMER CHEMICAL SOC

: WASHINGTON

: 2024

: Journal of Physical Chemistry C

: JOURNAL OF PHYSICAL CHEMISTRY C

: J PHYS CHEM C

: 129

: 1

: 353

: 358

: 6

: 1932-7447

: 1932-7455

DOI: https://doi.org/10.1021/acs.jpcc.4c07091

: https://doi.org/10.1021/acs.jpcc.4c07091

: https://research.utu.fi/converis/portal/detail/Publication/477943694

Nanopowders or films of pure and mixed oxides in nanoparticulate form have gained specific interest due to their applicability in functionalizing high-surface-area substrates. Among various other applications, our presented work primarily focuses on the behavior of TiO₂ as a photocatalyst deposited by atomic layer deposition (ALD) on a quartz particle. The photocatalytic activity of TiO2 on quartz particles grown by ALD was studied in terms of ALD growth temperature and post-treatment heating rate. Amorphous TiO₂ thin films (30 nm) were grown from tetrakis(dimethylamido)titanium (TDMAT) at 100 and 200 °C on quartz particles (0.35-3.5 μm) and crystallized using oxidative heat treatment at 500 °C with variable heating rates. The growth temperature was found to affect the TiO₂ defect structure: TiO₂ grown at 200 °C is black due to Ti³⁺ defects, whereas the film grown at 100 °C is white but contains some traces of the TDMAT ALD precursor. During the oxidative heat treatment, precursor traces desorbed and Ti3+ defects were oxidized. ALD TiO₂ grown at 100 degrees C crystallized as anatase, whereas the rutile-to-anatase ratio of 200 °C grown TiO₂ increased with the heating rate. The hydrogen production rate of mixed-phase TiO₂ was found to outperform that of anatase TiO₂.

bhuskute-et-al-2024-defect-mediated-crystallization-of-the-particulate-tio2-photocatalyst-grown-by-atomic-layer.pdf

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B.D.B. is thankful for the EDUFI fellowship, Jenny and Antti Wihuri Foundation (HA postdoc homing grant), Fortum and Neste Foundation, Finnish Foundation for Technology Promotion, Walter Ahlström Foundation, and Emil Aaltonen Foundation for research and incentive grants. J.S. was supported by the Vilho, Yrjö, and Kalle Väisälä Foundation of the Finnish Academy of Science and Letters. T.-P.R. wassupported by the Research Council of Finland postdoctoral fellowship (Decision Number 320165), the Finnish Center of Excellence program on Life-Inspired Materials LIBER (Decision Number 346107), and the EU H2020 Marie Sklodowska-Curie grant agreement 101022777. This work was supported by the Jane & Aatos Erkko Foundation (Project “Solar Fuels Synthesis”). This work is part of the Academy of Finland Flagship Programme, Photonics Research and Innovation (PREIN, Decision Number 320165).