Crystallization of hollow TiO2 into anatase at mild conditions, for improved surface recognition in selective photocatalysis

• Published in: Applied catalysis. A, General General, 2022-11, Vol.648, p.118912, Article 118912
• Main Authors: Ferreira, V.R.A., Azenha, M.A., Pereira, C.M., Silva, A.F.
• Format: Article
• Language: English
• Subjects: Anatase; Binding sites; Crystallization; Degradation; Hollow TiO2 microspheres; Microspheres; Photocatalysis; Photocatalytic selectivity; Roasting; Selective binding; Selectivity; Sol-gel; Titanium dioxide; Ultraviolet radiation
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2022.118912

The objective of this work was the exploration of low calcination temperature ranges (< 350 ºC) to obtain molecularly imprinted microspheres (MIM) with a high crystallinity as anatase, in cooperation of an acidic pretreatment aiming at the preservation of the hollow shape and also of the selective binding sites. It was confirmed the possibility of obtaining bilirubin-imprinted crystalline TiO2 microspheres (highly crystalline anatase, as confirmed by XRD) exhibiting higher photocatalytic efficiency associated especially with the hollow shape and calcination at lower temperatures (200 ºC or 250 ºC). It was with the calcination temperature of 250 ºC that the highest photocatalytic efficiency was obtained, under UV irradiation, associated with the highest adsorption selectivity (α(K) = 19) and degradation selectivity (α(k) = 2.7) observed for the degradation of the template against a closely related analogue compound. [Display omitted] •Calcination under mild conditions (200 and 250 ºC) preserved the selective mesoporous structure of the TiO2 layer.•Initial acidic treatment proved to be important to maintain the integrity of the hollow shape and selectivity.•It was possible to obtain highly crystalline anatase shells with calcinations at 200 and 250 ºC.•Photocatalytic efficiency and selectivity to the template (biliribin) much improved with calcinations at 250 ºC.