Facet-controlled synthesis and facet-dependent photocatalytic properties of SnO2 micropolyhedrons

The facet-dependent properties of SnO2 are of fundamental and practical importance. In this study, by adjusting the deposition temperature during chemical vapor deposition, octahedral SnO2 with the exposed (1 0 1) facet and two other kinds of SnO2 polyhedrons with (1 0 1) and (1 0 0) facets with different ratios are fabricated controllably based on the vapor-solid growth mechanism. A slight increase in the deposition temperature from 1030 to 1070 degrees C decreases the surface energy of the reduced (1 0 1) facet with Sn termination, leading to the formation of polyhedrons with different area ratios of (1 0 1) to (1 0 0) facets. By adopting the terephthalic acid fluorescent method, the SnO2 octahedrons are demonstrated to have the strongest photocatalytic activity due to the formation of surface states induced by 5s electrons of bivalent Sn on the (1 0 1) surface. The results reveal that the photocatalytic properties of SnO2 microcrystals can be enhanced by facet-controlled synthesis. (C) 2015 Elsevier B.V. All rights reserved.