Biomolecule-assisted hydrothermal synthesis and optical properties of Cu7S4 nanotubes

Abstract

Cu7S4 nanotubes were synthesized using a biomolecule DL-methionine-assisted hydrothermal method. The morphology and phase of the products can be controlled by adjusting the reaction parameters such as synthesis temperature, reaction time and the molar ratio of the reagents. We found that uniform polycrystal Cu7S4 nanotubes with diameters of 100-600 nm and lengths of 40-100 μm can be controllably synthesized at 200°C when the molar ratio of Cu(NO3)2 to DL-methionine in the synthesis system is 1:2. Similar Cu7S4 nanotubes can be obtained from D-or L- methionine systems. The bandgap energy of the Cu7S4 nanotubes was measured to be about 2.88 eV, a remarkable blue shift in comparison with that of bulk Cu7S4 (2.0 eV). We discussed the relationship between the products and the functional groups in the amphiphilic biomolecules. On the basis of our experimental data, we proposed that the Cu7S4 nanotubes were formed versus a self-sacrificing template mechanism. © Editorial office of Acta Physico-Chimica Sinica.