Dual-film optofluidic microreactor with enhanced light-harvesting for photocatalytic applications

Optofluidic microreactors are promising platform for photocatalytic reactions. However, the light transmission phenomenon is serious in optofluidic microreactors which makes a part of solar energy lose in surroundings. To resolve this problem, in this work, a novel dual-film optofluidic microreactor is proposed and fabricated by immobilizing TiO2 nanorod arrays on both the top and bottom internal wall of the microchamber. Such dual-film structure enables the transmitted light to be utilized by the bottom TiO2 film instead of being wasted, thus improving the light-harvesting capacity of optofluidic microreactor. Moreover, TiO2 nanorod arrays are employed as the photocatalytic film in this optofluidic microreactor to enlarge the specific surface area and facilitate the mass transfer. The photocatalytic performance and the kinetic properties of the dual-film optofluidic microreactor are evaluated by photocatalytic degradation of methylene blue. Results show that the proposed dual-film optofluidic microreactor yielded much higher degradation efficiency than the conventional one as a result of enhanced light-harvesting and improved mass transfer. In addition, the long-term testing proves that the durability of the dual-film optofluidic microreactor can be improved by operating it in a periodically rotated manner. In short, the TiO2 nanorod arrays-based dual-film optofluidic microreactor exhibits efficient light-harvesting and high durability and shows promising potential for photocatalytic applications.