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

Nanocrystalline CaTiO 3 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...

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Bibliographic Details
Published inElectrocatalysis Vol. 14; no. 3; pp. 353 - 364
Main Authors Klusáčková, Monika, Nebel, Roman, Macounová, Kateřina Minhová, Krtil, Petr
Format Journal Article
LanguageEnglish
Published New York Springer US 01.05.2023
Springer Nature B.V
Subjects
Admixtures
Apexes
Calcium titanate
Catalysis
Chemistry
Chemistry and Materials Science
Electrochemistry
Electron transfer
Energy Systems
Freezing
Graph theory
Nanocrystals
Original Research
Oxidation
Ozone
Particle size
Perovskites
Physical Chemistry
Single crystals
Ozone formation
Photo-electrochemistry
Water oxidation
Spray-freezing/freeze-drying synthesis
Calcium titanate
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Summary:Nanocrystalline CaTiO 3 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 CaTiO 3 surface facilitated by the surface states. The CaTiO 3 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
ISSN:1868-2529
1868-5994
DOI:10.1007/s12678-022-00801-y