Microwave Plasma Assisted Sol‐Gel Synthesis of TiO 2 Photocatalyst for DC Plasma Jet Driven Degradation of Methylene Blue

A new microwave plasma assisted sol‐gel (MPAS) technique was adopted to produce Titanium dioxide (TiO 2 ) photocatalyst by using pure and mixed stabilizers. The crystalline phases, composition, bandgap energy and surface morphology of TiO 2 were studied through SEM, XRD, FT‐IR, UV‐Visible spectroscopy and photoluminescence spectroscopy. The average particle size of MPAS synthesized TiO 2 nanoparticles remained smaller than the simple sol‐gel method while bandgap energy increased by 40 %. The rutile content and crystallinity of nanoparticles were also found higher in MPAS synthesized TiO 2 than the simple sol‐gel method. The type of stabilizer only effected the particle size but not the phase transformations of TiO 2 nanoparticles. TiO 2 photocatalyst with band gap of 3.06 eV was used to degrade methylene blue dye in water under the exposure of open atmosphere argon plasma jet. UV radiation intensity of the plasma jet at a distance of 2 cm was 576 μW/cm 2 , which reduced to 149 μW/cm 2 at 10 cm. The plasma jet produced some highly reactive species and UV radiations. The reactive species reacted with dye molecules while UV radiations promoted the activity of TiO 2 . The dye degradation efficiency of the process, under the combined effect of reactive species and TiO 2 activity, reached to 95 % after 30 min of plasma exposure time.