Construction of bimetallic Pd-Ag enhanced AgBr/TiO2 hierarchical nanostructured photocatalytic hybrid capillary tubes and devices for continuous photocatalytic degradation of VOCs

Combining high-efficient photocatalysts and well-designed photocatalytic reactors is a promising approach to realize the practical photocatalytic degradation of the volatile organic chemicals (VOCs). In this work, the PdAg/AgBr/TiO2 hierarchical nanostructure was synthesized via a hydrothermal approach followed by the photodeposition, ion-exchange, and the photo-reduction processes. The bimetallic Pd-Ag co-catalyst on AgBr/TiO2 composites presented enhanced photocatalytic activity in the photo-degradation of propylene, which was varied with Pd content. The high photocatalytic activity of the hybrid photocatalyst is derived from the high visible-light photocatalytic activity of AgBr and the improved charge separation of the Pd-Ag/AgBr/TiO2 hierarchical nanostructure. Finally, a self-container hydrothermal method was proposed and prepared the Pd-Ag enhanced AgBr/TiO2 hierarchical nanostructured photocatalytic hybrid capillary tubes. A well-designed continuous photocatalytic reactor was integrated by fixing the glass capillary tubes onto a pair of circled glass tubes with a Xe arc lamp in the center of the device. The reactor showed a high degradation efficiency of gaseous propylene over a large range of flow rates. Therefore, it possesses a high potential for the practical application to deal with the VOCs.