Crystal Size Dependence of the Photo-Electrochemical Water Oxidation on Nanoparticulate CaTiO3

0566049 - ÚFCH JH 2024 RIV US eng J - Journal Article
Klusáčková, Monika - Nebel, Roman - Minhová Macounová, Kateřina - Krtil, Petr
Crystal Size Dependence of the Photo-Electrochemical Water Oxidation on Nanoparticulate CaTiO3.
Electrocatalysis. Roč. 14, č. 3 (2023), s. 353-364. ISSN 1868-2529. E-ISSN 1868-5994
R&D Projects: GA MŠMT(CZ) LM2018124
Grant - others:Akademie věd - GA AV ČR(CZ) L200402001
Institutional support: RVO:61388955
Keywords : Calcium titanate * Ozone formation * Photo-electrochemistry * Spray-freezing/freeze-drying synthesis * Water oxidation
OECD category: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis)
Impact factor: 3.1, year: 2022
Method of publishing: Limited access

Nanocrystalline CaTiO3 materials with controlled particle size were prepared using spray-freezing/freeze-drying approach utilizing gelatine as a structure-directing agent. The resulting materials show characteristic particle size between 19 and 60 nm. The shape of the nanocrystals changes from cube-like single crystal containing particles into less regular isometric particles. Prepared materials as identified by X-ray diffraction analysis are formed by orthorhombic perovskite with small admixture of cubic phase. The ratio of both perovskite phases is independent of the particle size or prevailing crystal shape. All prepared materials show n-semiconducting character with band gap of ca 3.6 eV. They also show photo-electrochemical activity in water oxidation in acid media if a bias greater than 400 mV with respect to the flat band potential is applied. The specific photo-electrochemical activity decreases with increasing specific surface area. This behavior is attributed to increased probability of the electron transfer at the illuminated CaTiO3 surface facilitated by the surface states. The CaTiO3 materials also generate significant amount of ozone upon illumination in oxygen saturated solutions. The tendency to form ozone increases with increasing particle size suggesting that the ozone formation is hindered on materials with large number of low dimensionality states (crystal edges and vertices). Graphical Abstract: [Figure not available: see fulltext.].
Permanent Link: https://hdl.handle.net/11104/0337487