Synthesis of ZnO and SnO₂nanoparticles comparing two different sol-gel methods.

Metal oxides semiconductors (MOSs) are binary compounds formed by oxygen and metals (SnO₂, CuO, ZnO, NiO, Co₃O₄, TiO₂) which have physical-chemical properties and they have been studied because of its application versatility. Tin dioxide and Zinc oxide have been capturing attention in last years by precursor accessibility and inexpensive synthesis process, furthermore an ample assortment of applications. There are several synthesis methods, but this work is focused on Sol-Gel method since providing higher homogeneity, purity, and quality for products. Material properties might be varied by using different solvents and complexing agents. Due to aforementioned background, our interest is synthesis of ZnO and SnO₂ by two sol-gel methods each. First for ZnO, precursor ZnC₄H₆O₄ was dissolved with water, then Triton X-100 added, stirred 3 hours, ammonia was added, product was washed, dried and calcinated at 700 ^oC. By other hand, ZnC₄H₆O₄ was dissolved with water, stirred at 80 ^oC, pH adjusted to 10, product was dried, washed, dried and calcinated at 550 ^oC. For SnO₂, SnCl₄*2H₂O was precursor, dissolved with ethanol and pH adjusted to 4, product was washed, dried and calcined at 650 ^oC. Another way was dissolving SnCl₄*2H₂O with water, ammonia was added, filtered, washed and later dissolved with acetic acid and ethylen glycol was added, solution was stirred, a gel was obtained, It was dried and calcinated to 350 ^oC. Four obtained powders were characterized by Raman spectrometry and XRD. For ZnO with XRD both cases were defined as wurzite phase but when ZnC₄H₆O₄ was dissolved with water Raman shift shows a higher intensity. For SnO₂ with XRD both cases were defined as tin oxide tetragonal phase but when SnCl₄*2H₂O was dissolved with ethanol  Raman shift shows a higher intensity. Zinc oxide and tin oxide that show higher intensity can be deposited over SiO₂ substrates to be used for photocatalysis, bacterial inhibitors, photovoltaics, electronic and biomedical applications.