Synthesis and characterization of novel spinel Zn1.114La1.264Al0.5O4.271 nanoparticles

Novel spinel Zn1.114La1.264Al0.5O4.271 nanoparticles were synthesized using low-temperature gel combustion method and characterized by XRD, XPS, FE-SEM, TEM, BET, UV-Vis, FT-IR and fluorescence analyses. The XPS analysis revealed that the number of Zn2+ ions in the Oh holes was similar to 2.7 times greater than that in the T-d holes confirming the synthesized compound was not a mixture of different metal oxides but it was a normal spinel material. The average crystallite size measured for the sharpest peak at 2 theta approximate to 33 degrees in the XRD diagrams was about 25 nm for the fuel/metals ratios of 1:3 and 2:3, but it was similar to 15 nm for the fuel/metals ratios of 10:3 and 20:3. The FE-SEM micrographs showed puzzle like, leaf and spherical morphologies for the nanoparticles synthesized using starch, poly(vinyl alcohol) and glycerin fuels, respectively. Interestingly, with increasing the fuel/metals ratio, the calcination time was decreased significantly from about 24 h to about 15 min. The N-2-physisorption data illustrated that varying both the fuel type and pH of the solution affected the BET surface areas and pore volumes. The band gap of the nanoparticles synthesized with glycerin fuel was slightly greater (3.24 eV, smaller electron conductivity) than those of nanoparticles obtained using starch and poly(vinyl alcohol) fuels (3.11 and 3.12 eV, respectively). Accordingly, the semiconductor Zn1.114La1.264Al0.5O4.271 nanoparticles can find promissing applications as catalysts (in chemical synthesis), electrocatalysis (cathodic and anodic materials in solar cells and fuel cells), ceramics (in high temperature catalytic reactions as highly stable materials) and adsorbents (in air/wastewater treatments). (C) 2016 Elsevier B.V. All rights reserved.