Direct vapor transport synthesis of ZnGa2O4 nanowires with superior photocatalytic activity

ZnGa2O4 nanowires have been synthesized by a direct vapor transport process on c-sapphire substrate without any template under low temperature. Their structural and optical properties were characterized by field-emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS) X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), and photoluminescence (PL). Structural characterization revealed that the as-synthesized samples consist of cubic spinel ZnGa2O4 nanowires with 30–90 nm in diameter and 3–5 μm long. Room temperature photoluminescence show intense ultraviolet (375 nm) and green (530 nm) emissions originate from oxygen vacancies. Specifically, a near-band-edge emission centered at 283 nm was observed. The photocatalytic activity of ZnGa2O4 nanowires was evaluated by the degradation of methyl blue (MB) under ultraviolet light illumination. The results show that ZnGa2O4 nanowires exhibit high photocatalytic activity and is attributed to the enhanced light absorption and strong redox ability of photo-generated electron–hole pairs.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► ZnGa2O4 nanowires were synthesized by a direct vapor transport method. ► Intense green and UV emission observed at room temperature. ► Enhanced light absorption contribute to high photocatalytic activity.