Morphological Studies, Photocatalytic Activity, and Electrochemistry of Platinum Disulfide Nanoparticles from Bis(morpholinyl-4-carbodithioato)-platinum(II).

Abstract

Bis(morpholinyl-4-carbodithioato)-platinum(II) was synthesized and characterized using spectroscopic techniques and single-crystal X-ray crystallography. The Pt(II) complex crystallized in a monoclinic space group P21/n with a Pt(II) ion located on an inversion center coordinated two morpholinyl dithiocarbamate ligands that are coplanar to form a slightly distorted square planar geometry around the Pt(II) ion. The complex was thermolyzed at 120, 180, and 240 °C to prepare PtS2 nanoparticles. Powder X-ray diffraction patterns confirmed the hexagonal crystalline phase for the as-prepared PtS2 nanoparticles irrespective of thermolysis temperature. Bead-like shaped PtS2-120 nanoparticles with a particle size in the range of 12.46–64.97 nm were formed at 120 °C, while PtS2-180 prepared at 180 °C is quasi-spherical in shape with particles in the range of 24.30–46.87 nm. The PtS2-240 obtained at 240 °C is spherical with particles in the range of 11.45–46.85 nm. The broad emission maxima of the as-prepared PtS2 nanoparticles are ascribed to the particles’ broad size distributions. The photocatalytic degradation of methylene blue by the PtS2 nanoparticles shows a maximum efficiency of 87% for PtS2-240 after 360 min. The effects of photocatalytic dosage, irradiation time, pH medium, and scavengers were also evaluated. Cyclic voltammetry of the PtS2 nanoparticles showed a reversible redox reaction, while the electrochemistry of the as-prepared PtS2 indicates that the electron transfer process is diffusion-controlled.