Enhancing Ionic Selectivity and Osmotic Energy by Using an Ultrathin Zr‐MOF‐Based Heterogeneous Membrane with Trilayered Continuous Porous Structure

• Published in: Angewandte Chemie 2024-08, Vol.136 (35), p.n/a
• Main Authors: Yang, Zhen‐Jie, Yeh, Li‐Hsien, Peng, Yu‐Hsiang, Chuang, Yi‐Ping, Wu, Kevin C.‐W.
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Design; Energy conversion; Energy harvesting; Fluidics; Ion transport; Ion-selective membrane; Ionic diode; Membrane permeability; Membranes; Metal-organic frameworks; MOF membrane; Nanoarchitectonics; Nanochannels; Nanofluids; Osmotic power; Potassium chloride; Rivers; Seawater; Transport properties; Zirconium
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202408375

Designing a nanofluidic membrane with high selectivity and fast ion transport property is the key towards high‐performance osmotic energy conversion. However, most of reported membranes can produce power density less than commercial benchmark (5 W/m2), due to the imbalance between ion selectivity and permeability. Here, we report a novel nanoarchitectured design of a heterogeneous membrane with an ultrathin and dense zirconium‐based UiO‐66‐NH2 metal–organic framework (MOF) layer and a highly aligned and interconnected branched alumina nanochannel membrane. The design leads to a continuous trilayered pore structure of large geometry gradient in the sequence from angstrom‐scale to nano‐scale to sub‐microscale, which enables the enhanced directional ion transport, and the angstrom‐sized (~6.6–7 Å) UiO‐66‐NH2 windows render the membrane with high ion selectivity. Consequently, the novel heterogeneous membrane can achieve a high‐performance power of ~8 W/m2 by mixing synthetic seawater and river water. The power density can be largely upgraded to an ultrahigh ~17.1 W/m2 along with ~48.5 % conversion efficiency at a 50‐fold KCl gradient. This work not only presents a new membrane design approach but also showcases the great potential of employing the zirconium‐based MOF channels as ion‐channel‐mimetic membranes for highly efficient blue energy harvesting. We demonstrate a significantly promoted selectivity and blue energy harvesting performance by a novel nanoarchitectured design of a heterogeneous membrane with a trilayered pore structure of large geometry gradient from angstrom‐scale to nano‐scale to sub‐microscale, which is composed of an ultrathin zirconium‐based UiO‐66‐NH2 MOF and a highly aligned branched alumina nanochannel membrane.