Reprint of "Influence of chitosan–PEG binary template on the crystallite characteristics of sol–gel synthesised mesoporous nanotitania photocatalyst"

Highlights: • Binary templated (PEG and chitosan) mesoporous nano titania was prepared by sol–gel method. • PEG:chitosan in the ratio of 1:3 (P1-C3 titania) offered the best template effect. • P1-C3 titania had superior activity in degrading 4-chlorophenol under UV irradiation. • While, PEG acted as a physical template for mesopore formation. • Chitosan played a major role in defining the crystallite dimensions. - Abstract: Nano-titania is by far, the most studied material for its photocatalytic application in air and water pollution abatement. In this study, we have demonstrated the advantage offered by using a binary template of PEG and chitosan for the sol–gel synthesis of titania. Nano-titania samples were prepared using PEG, chitosan and the binary combination of these two as templates. XRD showed that all synthesized samples preserved the anatase structure. Titania sample prepared on 1% PEG and 3% chitosan as template (P1-C3 titania) possessed spherical shaped particles with an average particle size of 12.3 nm, a surface area of 82.9 m²/g and uniform dispersion. DRS UV–Vis spectra indicated that, P1-C3 titania showed blue shift in its absorption profile due to decrease in particle size. Consistent with the characteristics, the P1-C3 titania exhibited the highest photocatalytic activity for the degradation of 4-chlorophenol under UV irradiation, in comparison with all the synthesized photocatalytic systems and Degussa-P25. The chitosan bio template is believed to offer controlled growth of titania through Lewis base type interaction with Ti metallic centers in TiO₂. Such controlled growth route will be significant in synthesizing custom-made titania for its advanced applications in catalytic processes