Photo-Induced Active Ion Transport-Assisted Efficient Ionic Power Harvesting from Bioinspired Janus Dual-Field Heterostructures

Natural organisms have developed various biological ion channels/transporters to maintain normal life activities to adapt to changing environments. Significantly, ion transporters with active ion transport property show much more controllability on these activities due to a variety of external stimuli, giving guidance to construct artificial counterparts for overcoming the issues in simple nanofluidic systems restricted by self-diffusive ion transport. Herein, a 2D nanofluidic system based on a Janus membrane (i.e., JM) is constructed, which can achieve light-driven active ion transport and do favor for ionic power harvesting in electrolyte systems with equal concentrations. The JM is obtained through sequentially assembled montmorillonite (MMT) decorated with photoelectric molecules (i.e., PMMT) and MXene nanosheets. Due to the formed intramembrane electric field and temperature gradient caused by the efficient charge separation and localized thermal excitation under light illumination, a photovoltaic-driven force and thermo-osmotic are generated for preferential ion transport. In addition, the unidirectional active transport is employed to harvest ionic power, showing an output power density of 2.0 mW m(-2 )and a high-performance energy conversion efficiency of 8.3 x 10-4%. The effects of the light intensity, electrolyte concentration and species on energy conversion performance are investigated, showing the university for ionic power harvesting.