Phase-selectivity photocatalysis: a new approach in organic pollutants' photodecomposition by nanovoid core(TiO_2)/shell(SiO_2) nanoparticles

摘要

Core(TiO_2)/shell(SiO_2) nanoparticles, with a void layer between the TiO_2 core and the silica layer, act as phase-selectivity photo-catalysts for the photodecomposition of organic pollutants (gas phase) without any damage to their organic supports (solid phase).rnEven though the superior photocatalytic performance of titanium(iv) dioxide (TiO_2) has been known for almost 30 years, a limitation quite prohibits its application in investigations. Because of the high photocatalytic activity and photo-stabilization of TiO_2, photocatalytic processes to decompose organic pollutants by oxidation utilizing TiO_2, either in the form of unsupported suspended TiO_2 powder or in the form of TiO_2 immobilized on supports, have been the subject of extensive research. Considering that it is difficult to deal with the powder, there is a preference to use immobilized TiO_2 as the catalyst in photocatalytic decomposition. However, such immobilized systems suffer from some serious drawbacks that limit their utilization, because organic supports such as textiles, paints, plastic films etc., will be photo etched by the high redox activity of TiO_2. The core/shell technique is the most common method that people use to obtain shell-protected TiO_2 nanoparticles in order to avoid the instability of the supports.