Effect of chiral-arrangement on the solar adsorption of black TiO2-SiO2 mesoporous materials for photodegradation and photolysis

Aiming at exploring the relationship between photocatalysts with nanoscale chiral structures and their photocatalytic activity, we fabricated a novel chiral-arranged TiO2-SiO2 mesoporous material with high visible-light absorption and photocatalytic performance. Through a soft template route using a chiral surfactant and a co-structure-directing agent, the mesoporous materials with helical-spherical depositions could form in under low reaction temperature (≤10 °C). The asymmetric helical microstructures introduced numerous oxygen vacancies and Ti-N bonds into the materials, thus significantly promoting their visible-light response and photocatalytic performance. The chiral-arranged TiO2-SiO2 mesoporous material had high substantial visible-light-driven photocatalytic performance, including the degradation for rhodamine B in water and the production of hydrogen with a sacrificial reagent. The optimal removal rate of chiral-arranged TiO2-SiO2 materials for rhodamine B exceeded 97% irradiated by visible light. With increasing reaction temperature, the formation of TiO2 agglomerations could not deposit with the silica chiral frames and no chiral structure formed in the materials, thus exhibiting no visible-light response of TiO2-SiO2 materials.