Synthesis of visible light-responsive cobalt-doped TiO 2 nanoparticles with tunable optical band gap

摘要: Visible light-responsive photocatalysts are the most promising candidates for green bioremediation processes that will degrade toxic organic industrial waste into harmless compounds. Among photocatalysts, TiO2 is best suited large-scale photo-induced mainly because of low cost and abundance. The major obstacle in its utilization as photocatalyst poor response to sunlight due wide energy band gap. This article reports sol–gel synthesis pristine cobalt-doped nanoparticles (TNPs). Titanium (IV) isopropoxide hydrolyzed condensed amorphous titanium dioxide gel by water/ethanol under acidic conditions. Irrespective Co concentration, TNPs always crystallize anatase phase when calcine at 500 °C. No signature other isomorphous phases, i.e., rutile or brookite, detected. optical gap (0 % doped) 3.03 eV (λ = 409 nm), which decreases up 1.93 eV (λ = 642 nm) concentration matrix increases from 0 2 %. Co(+2) substitution Ti(+4) site generates additional oxygen vacancies unit cell, introduces extra levels forbidden reduces indirect TNPs. doping makes them sensitive visible radiation, hence, their photoresponse expected be better than bulk titania, active only UV region electromagnetic spectrum.