Synthesis of a heterojunction CoTiO3/Co3O4 nano-composite thin film with superior photocatalytic activity and reusability: Effect of calcination temperature on phase transformation and effect of oxidants on enhanced degradation of Indo Light Blue dye

Mohammad Hossein Habibi; Elahe Shojaee

doi:10.1016/j.saa.2019.117796

Synthesis of a heterojunction CoTiO₃/Co₃O₄ nano-composite thin film with superior photocatalytic activity and reusability: Effect of calcination temperature on phase transformation and effect of oxidants on enhanced degradation of Indo Light Blue dye

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Mar 15:229:117796. doi: 10.1016/j.saa.2019.117796. Epub 2019 Dec 9.

Authors

Mohammad Hossein Habibi¹, Elahe Shojaee²

Affiliations

¹ Nanotechnology Laboratory, Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Islamic Republic of Iran. Electronic address: habibi@chem.ui.ac.ir.
² Nanotechnology Laboratory, Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Islamic Republic of Iran.

PMID: 31896052
DOI: 10.1016/j.saa.2019.117796

Abstract

CoTiO₃/Co₃O₄ heterojunction nano-composite was grown by a coprecipitation method at low temperature. The effects of calcination temperature on the phase composition, crystallization and morphology of the cobalt titanates were also examined. Notably, the novel nano-crystalline cobalt titanate with a narrow band gap to coulpe with cobalt oxide (Co₃O₄) by a direct coprecipitation method (CoTiO₃/Co₃O₄) was attained. The Nano-crystalline samples were systematically characterized by TG/DTG, XRD, DRS, FESEM, FT-IR, EDX and XPS techniques. The results showed that CoTiO₃/Co₃O₄ nano-composite hetero-junction was formed at 650 °C, while at 750 °C a single phase CoTiO₃ nano-crystal was prepared. Photocatalytic activities indicated the heterostructured CoTiO3/Co₃O₄ nano-composite exhibited much higher photocatalytic activity for degradation of Indo Light blue under visible light irradiation with added oxidants (K₂S₂O₈, KBrO₃, and H₂O₂). The charge separation of CoTiO3 and Co₃O₄ would result the enhanced visible-light harvesting ability and longer lifetime of photogenerated charge carriers. The stability and reusability of catalysts during four successive cycles were resulted. Finally, a possible mechanism responsible for the charge separation and improved photocatalytic activity was proposed.

Keywords: Charge separation; CoTiO(3)/Co(3)O(4); Heterojunction; Indo Light Blue dye; Nano-composite; Oxidant; Phase transformation; Photocatalytic; Thin film.