Advanced design of sol-gel derived multilayered cerium titanate films: structural, surface, photoelectrochemical and photocatalytic properties and photocatalytic properties
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MCPh_2024.pdf (11.48 MB)
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0009-0001-3112-2989 Date
2024-07-08
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Abstract
Crystallization of Ce2Ti2O7 in the mixture of TiO2 and CeO2 has been achieved by the three-layered coating of cerium - titanium mixed sol of the 1 : 1 metal molar ratio on a glass substrate after thermal treatment of interlayers at 300°C or 600°C and the last layer at 450°C or 600°C in the air as proven by XRD, SAED and Raman spectroscopy. The monoclinic and its mixture with pyrochlore crystal structures are formed in the case of the last layer heating at 450°C and 600°C, respectively. It is shown that Ce ions retarded TiO2 crystallization, leading to the increase in the specific surface area of some films that, in turn, depends on the calcination temperature. The formation of Ti-O Ce bonds on the surface of the films was proven by the noticeable shift of Ti2p and O1s XPS maxima compared to TiO2 ones. The additional peaks in Ti2p, O1s and Ce3d XPS spectra belonging to the common bonds between the metal ions are identified for the first time. The preferential formation of Ti-O-Ce fragments at the treatment of all layers at 600°C is noted. The bandgap energy and band-edge positions of Ce2Ti2O7 were firstly determined by photoelectrochemical measurements. The inactivity of the films in photocatalytic reductive and oxidative processes is caused by the unfavorable position of the valence band causing the recombination of the photoformed electron-hole pair.