Preparation of ZnS-Based Nanocomposites by Thermolysis of Zinc-Containing Monomers in the Presence of Thiourea: Their Characterizations and LPG Sensing Applications

The thermolysis of zinc fumarate and its complexes with 2,2′-dipyridyl, 1,10-phenanthroline, and 4′-phenyl-2,2′:6′,2’’-terpyridine in the presence of thiourea results in the formation of ZnS-based metal-polymer nanocomposites. The zinc fumarate complex with 4′-phenyl-2,2′:6′,2’’-terpyridine is a 1D coordination polymer formed from a Zn(II)-terpyridine node bridged by fumarate ligands. Each zinc atom has five coordinations and is chelated by three ligand nitrogen atoms and two oxygen atoms of the fumarate fragments to form a ZnN₃O₂ chelate node. The polyhedron of the Zn(II) moiety is close to an ideal tetragonal pyramidal structure. According to X-ray powder diffraction data, all zinc sulfide-containing thermolysis products have high phase purity and a narrow particle size distribution. The resulting nanocomposites were used to create liquefied petroleum gas (LPG) sensors at room temperature. The sensors demonstrate satisfactory response times of 4.8 to 7.2 s and short relaxation times of 8.3 to 17.4 s. The devices are characterized by fairly stable operation for at least 45 days. The maximum discrepancy between recorded readings is 2.78%. The manufactured sensors have great potential for use a sensitive element of LPG in sensors that can be used for LPG monitoring.