Synthesis, thermal stability, and photocatalytic activity of nanocrystalline gallium nitride via the reaction of Ga2O3 and NH4Cl at low temperature

Nanocrystalline gallium nitride (GaN) was prepared via one simple route by the reaction of metallic magnesium powders with gallium sesquioxide (Ga2O3) and ammonium chloride (NH4Cl) in an autoclave at 650 °C. X-ray powder diffraction (XRD) pattern indicated that the product was hexagonal GaN, and the cell constant was (a = 3.18962 Å, c = 5.18674 Å). Scanning electron microscopy (SEM) images showed that the sample consisted of particles with an average size of about 30 nm in diameter. Raman spectroscopy study showed a frequency shift towards lower side due to the polycrystalline nature of the synthesized GaN. The hexagonal GaN powder exhibited good photocatalytic activity in degradation of Rhodamine-B (RhB) under 300 W mercury lamp light irradiation. The product was also studied by the thermogravimetric analysis (TGA). It had good thermal stability and oxidation resistance below 750 °C in air.