Preparation by Solvothermal Synthesis, Growth Mechanism, and Photocatalytic Performance of CuS Nanopowders

Various CuS nanostructures, including nanoflowers, doughnut-shaped nanospheres, dense nanospheres, and mixtures of nanoneedles, nanoparticles, and nanoplates, were synthesized from different copper and sulfur sources by a solvothermal method. The formation mechanisms along with photocatalytic properties for the degradation of rhodamine B (RhB) under visible-light irradiation were investigated in this study. The experimental results indicate that when the sulfur source is fixed at CS(NH2)2 in the solvothermal reaction, spherical nanoflowers, doughnut-shaped nanospheres, and dense nanospheres could be synthesized by using CuCl2, Cu(NO3)2, and CuSO4 as the copper source, respectively. Furthermore, atypical nanoflowers and a mixture of nanoneedles, nanoparticles, and nanoplates could be obtained when the sulfur source was switched to Na2S2O3 and Na2S with a fixed copper source of CuCl2. The energy gaps calculated from the light absorption spectrum were 1.61, 1.93, 2.01, 1.70, and 1.82 eV for the spherical nanoflowers, doughnut-shaped nanospheres, dense nanospheres, atypical nanoflowers, and the mixture of nanoneedles, nanoparticles, and nanoplates respectively. Among these five samples, three powders composed of spherical nanoflowers, atypical nanoflowers as well as a mixture of nanoneedles, nanoparticles, and nanoplates exhibited excellent photocatalytic properties and can degrade rhodamine B completely in an hour.