Preparation And Properties Of Nanostructured MGaS₂ （M=Cu,Ag）

Wurtzite CuGaS2 was successfully synthesized in a facile one-pot hydrothermal process using CuCl, Ga(NO3)3 and thioacetamide as reagents. The as-prepared product was characterized with X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and UV-vis spectroscopy. The results indicate that the as-prepared sample is an aggregation of wurtzite CuGaS2 nanosheets and nanorods, and possess high crystallinity. This CuGaS2 hierarchical nanostructure can exhibit a strong emission at 832 nm with full width athalf maximum of approximate 20 nm. Furthermore, the application of CuGaS2 obtained in the trace detection of L-noradrenaline was explored as a photoluminescent probe. In addition, the as-prepared CuGaS2 possess high sensitivity to L-noradrenaline in water with a detectable concentration of 5.0 ×10-7 mol·L-1 when it used as a photoluminescent probe, implying that it is a promising candidate in the field of biological and chemical sensing in future.A compact CuGaS2 ultrathin film with crystallinity was prepared in an improved layer-by-layer self-assembled process following heat treatment and characterized with X-ray diffraction, Field scanning electron microscopy (FSEM), Thermogravimetric analysis (TGA). The results show that a tetragonal phase of CuGaS2 film with thermal stability was fabricated and the surface is smooth and dense. Then, the effect of layers on the optical properties over the CuGaS2 self-assembled film was studied. The CuGaS2 ultrathin film exhibits a strong emission at 829 nm with full width at half maximum of approximate 12 nm and possesses high sensitivity to L-noradrenaline with a detectable concentration of 2.83 ng/cm2.Crystalline tetragonal quasi-rounded AgGaS2 nanoplates with a diameter of about 40 nm were successfully synthetized by a facile one-pot hydrothermal process. The as-prepared product was characterized with X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorptionedesorption isotherms and UV-vis spectroscopy. Meanwhile, photocatalytic H2 evolution from water over the as-prepared AgGaS2 nanoplates loaded with CuS was explored using Na2S and Na2SO3 as sacrificial reagents. The results indicate that the AgGaS2 nanoplates loaded with CuS is an efficient photocatalyst under visible irradiation. More importantly, the photocatalytic H2 evolution is very rapid in the presence of the AgGaS2 nanoplates with CuS. In the first hour of irradiation, more than 65% of the total hydrogen production can be obtained and the rate is up to 772 mmol·h-1·g-1. Furthermore, for practical purposes, the photocatalytic H2 evolution was studied as a function of content of loaded CuS, hydro thermal reaction temperature, hydrothermal reaction time, dosage of photocatalyst, and concentration of sacrificial reagents, respectively. At last, the formation mechanism of AgGaS2 nanoplates and the photocatalytic mechanism were preliminarily discussed.