Size-tunable Zn 2 SnO 4 octahedra possessing two lattice phases for thiol-ene reaction

Abstract

By adjusting the volume of LiOH used, octahedral Zn 2 SnO 4 particles with average sizes of 285 nm, 655 nm, and 1.5 μm have been synthesized hydrothermally.Observation of several additional X-ray diffraction (XRD) peaks suggests presence of a trigonal phase instead of the normal cubic phase of Zn 2 SnO 4 . Synchrotron XRD analysis verifies that the 655 nm and 1.5 μm octahedra possess a trigonal phase with bulk and surface layer lattices differing by slight cell constant changes, while the 285 nm octahedra are better fitted with a trigonal bulk lattice and a cubic phase in the thick surface layer. High-resolution transmission electron microscopy (HR-TEM) characterization also reveals distinct lattice point differences in the crystal bulk and surface layer. These structural features should be important to their significant band gap shifts despite the large particle dimensions. Attributed to better light absorption, the 1.5 μm octahedra showed the best dye photodegradation activity. They also 2 exhibited the best efficiency in the thiol-ene reaction to couple thiolphenol and styrene to generate thioether. The particle size-and shape-related lattice variations are broadly present in semiconductor crystals to affect their various properties.