Journal
APPLIED SURFACE SCIENCE
Volume 447, Issue -, Pages 627-635Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.apsusc.2018.04.049
Keywords
Perovskite oxides; SrTiO3; Ti-rich surface; Photocatalytic CO2 reduction
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Funding
- National Nature Science Foundation of China [21473248]
- CAS-SAFEA International Partnership Program for Creative Research Teams
- Youth Talent Support Program of Shaanxi University of Science Technology
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Perovskite oxide SrTiO3 is a promising semiconductor photocatalyst for CO2 reduction, which has two possible chemical surfaces-TiO2-terminated and SrO-terminated surfaces. Up to now, the effect of chemical surface and its modification on CO2 adsorption, activation and sequential photocatalytic reduction is not established. In the work, SrTiO3, surface-Ti-rich SrTiO3 and Sr(OH)(2)-decorated SrTiO3 were prepared and their structural, surface, and optical properties and photocatalytic activity were explored. It is found that the absorption edge of surface-Ti-rich SrTiO3 shifted toward visible-light region as compared with that of the other two photocatalysts, which is attributed to the decreased Ti 3d ground-state level at the surface. Bicarbonate-(HCO3-) and bidentate carbonate-like (b-CO3=) species are the main species for CO2 adsorption on the surface-Ti-rich SrTiO3, whereas, besides HCO3- and b-CO3=, plenty of monodentate carbonate-like species (m-CO3=) that has relatively low reactivity is present on the SrTiO3 and Sr(OH)(2)-decorated photocatalysts. As a result, the surface-Ti-rich SrTiO3 exhibits the highest activity for CO2 reduction. Furthermore, although Sr(OH)(2)-decoration and SrO-terminated surfaces facilitate CO2 fixing, the produced surface species are attached to the weakly active Sr ions, giving rise to the lower reactivity. The present work might supply a guide for designing highly active perovskite-type semiconductors for photocatalysis. (C) 2018 Elsevier B.V. All rights reserved.
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