Synthesis and characterization of cauliflower-like ZnS microspheres by simple self-assembly method

Abstract Cauliflower-like ZnS microspheres comprising ZnS nanoblock-like structures were fabricated by a simple one-step self-assembly method involving a hydrothermal process at 150 °C for 10 h using Zn(CH 3 COO) 2 and Na 2 S 2 O 3 ·5H 2 O starting materials in an aqueous solution. The synthesized samples were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), and Brunauer–Emmett–Teller (BET) analysis. The photocatalysts were evaluated using the photodecomposition of methylene blue under UV light. The aqueous solutions had a pH 7, and exhibited the presence of a suspension of cauliflower-like ZnS microspheres, about 3–5 μm in diameter constructed of ZnS nanoblocks 2 /g, a pore volume of 0.0252 cm 3 /g, and a pore diameter of 3.77 nm, as determined by BET analysis. The photocatalytic degradation rate followed a pseudo-first-order equation. The kinetic constant ( k 1 ) of the cauliflower-like ZnS microspheres was 5.11×10 −2  min −1 .