Facile fabrication of mesoporous SiO2@(cTiO2/BiOI) heterojunctions with enhanced photocatalytic properties due to large surface area for contact with pollutants

Abstract

In order to fabricate photocatalysts possessing large surface area to contact with pollutants, mesoporous SiO2@TiO2 was prepared by step sol–gel method within the presence of cetyl trimethylammonium bromide templates. After removal of the surfactant by calcination or acid drawing, BiOI was inlayed on SiO2@TiO2 by successive ionic adsorption method. The catalysts with high crystalline TiO2 component, which formed in the calcination process for the removal of surfactant, showed higher photocatalytic activity under UV irradiation. More than 95% of 10 mg/L of methyl orange, methylene blue and tetracycline hydrochloride was degraded by 12 mg of the catalysts within 60 min. The improved catalytic effect derived from the enhanced charge transfer at the interface and the easy contact of pollutants with the catalysts. The catalytic mechanism was further studied and the possible degradation position of methyl orange after attack by active species was analyzed by Material Studio through calculating the electron density change.

Keywords

• Mesoporous catalysts
• TiO2/BiOI heterojunction
• MO
• Electron density