Effect of annealing on the conversion of ZnS to ZnO nanoparticles synthesized by the sol-gel method using zinc acetate and thiourea

Abstract

A systematic study is presented on the conversion of zinc sulfide to zinc oxide nanoparticles as a function of annealing temperature. Zinc acetate dihydrate (Zn(CH3COO)2.2H2O) and thiourea (NH2CSNH2) are used as precursors to synthesize ZnS and then ZnO. The aqueous solution of the precursor was refluxed at 90°C for over 12 h. The synthesized complex was then annealed at 300°C, 500°C, 700°C, and 900°C in air for one hour. From elemental analyses, it was found that the as-synthesized powder is a mixture of ZnS and ZnO, which annealing later converts to the zinc oxide phase only. The morphological observations revealed spherical particles of various sizes (20 nm to 300 nm) while increasing the annealing temperatures. A drastic change in the vibration bands is noticed with annealing. Photoelectron peaks related to sulfur and carbon are observed for synthesized powder, whereas, these peaks disappeared when annealed at 500°C.

Differential Antimycotic and Antioxidant Potentials of Chemically Synthesized Zinc-Based Nanoparticles Derived from Different Reducing/Complexing Agents against Pathogenic Fungi of Maize Crop

“…The conspicuous broadband (3690 to 2975 cm −1 ) was observed in starch (RA), and albumin, starch and cellulose (CA) which can be ascribed to hydroxyl (O-H) and amine (N-H) group vibrations. Similar peaks have also been reported for thiourea derived ZnNPs [26].…”

“…The particle size of less than 10 nm have been reported for NaOH-ethanol reaction mix [ 43 ] while ZnNPs generated from NaOH-isopropanol reaction mixture formed particles with the mean size dimensions of 189.0 ± 6.0 and 447.0 ± 22.0 nm by sonochemical and hydrothermal techniques respectively [ 47 ]. However, unlike Chen et al [ 30 ] the ZnNPs size was larger for the albumin (CA) ZnNPs while similar size distribution and average size have been observed for thiourea (RA) [ 26 ], cellulose (CA) [ 29 ], and starch (CA) ZnNPs [ 27 ].…”

“…Six different ZnNMs samples were prepared using soluble zinc salts (zinc acetate/zinc nitrate/zinc chloride) as the precursors. The reducing/complexing-capping agents used in the study were sodium hydroxide [ 25 ], thiourea [ 26 ] and natural polymers such as starch [ 27 , 28 ], and cellulose-nanocomposite [ 29 ], and protein (Bovine-serum albumin (BSA)) [ 30 ]. The brief protocols depicting the schematic steps have been provided in Figure 1 .…”

One‐Step Synthesis of Visible Range Luminescent Multicomponent Semiconductor Composites Based on Graphitic Carbon Nitride

“…In the case of unlimited supply of oxygen in the ambient atmosphere, sulfur from ZnS reacts with oxygen, producing gaseous sulfur dioxide SO 2 and ZnO. [ 31 ] So, ZnS should be completely converted into ZnO at a temperature higher than 500 °C, and all sulfur must be evaporated from the residue. [ 31 ] However, in our experiments, the material synthesized at a temperature higher than 550 °C contains high EDX detectable amount of sulfur.…”

“…[ 31 ] So, ZnS should be completely converted into ZnO at a temperature higher than 500 °C, and all sulfur must be evaporated from the residue. [ 31 ] However, in our experiments, the material synthesized at a temperature higher than 550 °C contains high EDX detectable amount of sulfur. Moreover, XRD and XPS detect both ZnS and ZnO crystal phases in the residue.…”