Dual‐Functional Super‐Assembled Mesoporous Carbon‐Titania/AAO Hetero‐Channels for Bidirectionally Photo‐Regulated Ion Transport

Abstract Photo‐regulated nanofluidic devices have attracted great attention in recent years due to their adjustable ion transport in real time. However, most of the photo‐responsive nanofluidic devices can only adjust the ionic current unidirectionally, and cannot simultaneously increase or decrease the current signal intelligently by one device. Herein, a mesoporous carbon‐titania/ anodized aluminum hetero‐channels (MCT/AAO) is constructed by super‐assembly strategy, which exhibits dual‐function of cation selectivity and photo response. The polymer and TiO 2 nanocrystals jointly build the MCT framework. Polymer framework with abundant negatively charged sites endows MCT/AAO with excellent cation selectivity, and TiO 2 nanocrystals are responsible for the photo‐regulated ion transport. High photo current densities of 1.8 mA m −2 (increase) and 1.2 mA m −2 (decrease) are realized by MCT/AAO benefiting from the ordered hetero‐channels. Significantly, MCT/AAO can also achieve the bidirectionally adjustable osmotic energy by alternating the configurations of concentration gradient. Theoretical and experimental results reveal that the superior photo‐generated potential is responsible for the bidirectionally adjustable ion transport. Consequently, MCT/AAO performs the function of harvesting ionic energy from the equilibrium electrolyte solution, which greatly expands its practical application field. This work provides a new strategy in constructing dual‐functional hetero‐channels toward bidirectionally photo‐regulated ionic transport and energy harvesting.