Morphology effect of honeycomb-like inverse opal for efficient photocatalytic water disinfection and photodegradation of organic pollutant

Abstract

Morphology is crucial component to achieve high photon utilization efficiency and efficient photocatalytic activity. In this work, novel honeycomb-like inverse opals were fabricated by a simple sol-gel method combined with a self-assembly polystyrene (PS) opal as template. The obtained materials exhibit unique 3D ordered porous structure with center-to-center distance of about 200nm, which lead to periodic modulations of light propagation and strengthen light absorption of materials. Photocatalytic activity of TiO2 with morphology of honeycomb and bulk, with or without doping Mg2+ was comparatively investigated by disinfection of bacteria and photodegradation of organic pollutant. Morphology evolution of TiO2 from bulk to honeycomb would increase specific surface area and strengthen light adsorption, which could largely strengthen photocatalytic activity of honeycomb-like TiO2. After Mg2+ is doped, it was found that Mg-TiO2 systems exhibited much higher activity than their counterpart due to decreased band gap. In this way, water disinfection of 100% inactivation of bacteria was achieved under visible light. Highly reactive h+ and O2− were found to be major reactive species and a possible mechanism was reasonably proposed.