Water-Induced Thermolytic Formation of Homogeneous Core−Shell CuS Microspheres and Their Shape Retention on Desulfurization

Abstract

Homogeneous inorganic core−shell microspheres made from hexagonal CuS are synthesized via thermolysis of Cu(R2dtc)2 (R = octyl, dtc = dithiocarbamate) precursor at 130−180 °C under N2 flow, optimally at 180 °C for 0.5 h. Scanning electron microscopy (SEM) analyses indicate that the core−shell microspheres have an average diameter of 1.74 μm (σ = ±12.7%) with a shell thickness of about 225 nm. Their formation is induced by the small amount of water in the precursor. A tentative formation mechanism is speculated. Interestingly, the as-made cupric sulfide CuS microspheres undergo a reduction to tetragonal cuprous sulfide Cu2S microspheres without morphology changes via solid-state annealing at 400 °C under N2 atmosphere. The microspheres made over 400−700 °C are invariably tetragonal Cu2S phase.