Supplementary material from "Orientation-dependent structural and photocatalytic properties of LaCoO<sub>3</sub> epitaxial nano-thin films"

Published on 2018-02-12T09:37:46Z (GMT) by
LaCoO<sub>3</sub> epitaxial films were grown on (100), (110) and (111) oriented LaAlO<sub>3</sub> substrates by the polymer-assisted deposition method. Crystal structure measurement and cross-section observation indicate that all the LaCoO<sub>3</sub> films are epitaxially grown in accordance with the orientation of LaAlO<sub>3</sub> substrates, with biaxial compressive strain in the <i>ab</i> plane. Owing to the different strain directions of CoO<sub>6</sub> octahedron, the mean Co–O bond length increases by different amounts in (100), (110) and (111) oriented films compared with that of bulk LaCoO<sub>3</sub>, and the (100) oriented LaCoO<sub>3</sub> has the largest increase. Photocatalytic degradation of methyl orange indicates that the order of photocatalytic activity of the three oriented films is (100) > (111) > (110). Combined with analysis of electronic nature and band structure for LaCoO<sub>3</sub> films, it is found that the change of the photocatalytic activity is closely related to the crystal field splitting energy of Co<sup>3+</sup> and Co–O binding energy. The increase in the mean Co–O bond length will decrease the crystal field splitting energy of Co<sup>3+</sup> and Co–O binding energy and further reduce the value of band gap energy, thus improving the photocatalytic activity. This may also provide a clue for expanding the visible-light-induced photocatalytic application of LaCoO<sub>3</sub>.

Cite this collection

Zhang, Yan-ping; Liu, Hai-feng; Hu, Hai-long; Xie, Rui-shi; Ma, Guo-hua; Huo, Ji-chuan; Wang, Hai-bin (2018): Supplementary material from "Orientation-dependent structural and photocatalytic properties of LaCoO3 epitaxial nano-thin films". The Royal Society.