Structural, optical and morphological study of sol-gel synthesized titanium dioxide incorporated with transition metal elements (silver and cobalt)

Titanium dioxide has been utilized since 1972 in plethora of fields such as in mitigation of harmful contaminants from environment. In this manuscript, 5 mol % silver and 6 mol % cobalt were incorporated with 89 mol % titanium dioxide (Ti_0.89 Ag_0.05Co_0.06O₂) using sol-gel technique. Ti_0.89 Ag_0.05Co_0.06O₂ (sample) was characterized by using X-ray diffraction, UV-Vis spectroscopy, Photoluminescence, Fourier transform infrared (FT-IR), Field emission scanning electron microscopy (FESEM) and Energy dispersive X-ray (EDX) spectrum. X-ray Diffraction (XRD) spectrum unveiled secondary phases and outlined the tensile strain in the sample. Utilizing Debye Scherrer method, Modified Scherrer method and W-H plot, the average crystallite size was calculated in the range (40 ~ 64) nm. The energy band gap 2.96 eV was estimated from Tauc plot. The low band gap of sample as compared to wide band gap of pristine TiO₂ (band gap: 3.2 eV) outlined shift towards higher wavelength in absorption spectrum. Photoluminescence spectrum confirmed the defects or impurity states formed due to intercalation of silver and cobalt transition metal elements. Fourier transform Infrared (FT-IR) spectrum displayed inculcation of silver and cobalt elements in titanium dioxide. The strong transmission band 500–800 cm^-1 was associated to Ti-O strain vibrations. Field emission scanning electron microscopy (FESEM) images illustrated irregular spherical morphology and agglomerated distribution with average particle size 60 nm. Energy Dispersive X-ray (EDX) analysis technique confirmed the presence of titanium, oxygen, silver, and cobalt atoms.