Inverted core–shell structured hollow particles for improved volatile organic compounds removal and photocatalytic regeneration

Abstract

As the amount of time people spend indoors increases, the impact of indoor air quality on health has become more important, and numerous studies have been conducted to eliminate indoor air pollutants such as volatile organic compounds (VOCs). Among the several methods for removing VOCs, the adsorption is the most widely used in that it requires a simple mechanism and low energy, but has a limitation in that it is difficult to regenerate after saturation. In order to solve this problem, composite materials combining adsorbents and photocatalysts have been developed, but there is still an issue that the photocatalytic activity can be lowered by covering the surface of the photocatalyst with the adsorbent. Here, mesoporous carbon/silica/titania double shell hollow nanoparticles (MC/SiO2/TiO2 HNPs) are prepared through etching, calcination and carbonization of polystyrene/polyacrylonitrile/SiO2/TiO2 multi-layered core/shell nanoparticles. Attributed to the high specific surface area of the MC/SiO2/TiO2 HNPs, high VOCs adsorption efficiency can be achieved. Moreover, the photocatalytic activity can be maximized since the TiO2 shell is exposed to the surface without any covering materials.