Unidirectional ion transport in nanoporous carbon membranes with a hierarchical pore architecture

Lu Chen; Bin Tu; Xubin Lu; Fan Li; Lei Jiang; Markus Antonietti; Kai Xiao

doi:10.1038/s41467-021-24947-3

Unidirectional ion transport in nanoporous carbon membranes with a hierarchical pore architecture

Nat Commun. 2021 Jul 30;12(1):4650. doi: 10.1038/s41467-021-24947-3.

Authors

Lu Chen^#^{1

2

3}, Bin Tu^#⁴, Xubin Lu^#^{5

6

7}, Fan Li⁸, Lei Jiang^{2

9}, Markus Antonietti³, Kai Xiao^{10

11}

Affiliations

¹ Department of Biomedical Engineering, Southern University of Science and Technology (SUSTech), Shenzhen, China.
² Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, China.
³ Department of Colloids Chemistry, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
⁴ CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, China.
⁵ Gansu Province Organic Semiconductor Materials and Technology Research Center, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, China. xubin.lu@mail.lzjtu.cn.
⁶ National Green Coating Equipment and Technology Research Center, Lanzhou Jiaotong University, Lanzhou, China. xubin.lu@mail.lzjtu.cn.
⁷ Institute of Chemistry, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany. xubin.lu@mail.lzjtu.cn.
⁸ Max Planck Institute of Microstructure Physics, Halle (Saale), Germany.
⁹ CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.
¹⁰ Department of Biomedical Engineering, Southern University of Science and Technology (SUSTech), Shenzhen, China. xiaokai@iccas.ac.cn.
¹¹ Department of Colloids Chemistry, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany. xiaokai@iccas.ac.cn.

^# Contributed equally.

Abstract

The transport of fluids in channels with diameter of 1-2 nm exhibits many anomalous features due to the interplay of several genuinely interfacial effects. Quasi-unidirectional ion transport, reminiscent of the behavior of membrane pores in biological cells, is one phenomenon that has attracted a lot of attention in recent years, e.g., for realizing diodes for ion-conduction based electronics. Although ion rectification has been demonstrated in many asymmetric artificial nanopores, it always fails in the high-concentration range, and operates in either acidic or alkaline electrolytes but never over the whole pH range. Here we report a hierarchical pore architecture carbon membrane with a pore size gradient from 60 nm to 1.4 nm, which enables high ionic rectification ratios up to 10⁴ in different environments including high concentration neutral (3 M KCl), acidic (1 M HCl), and alkaline (1 M NaOH) electrolytes, resulting from the asymmetric energy barriers for ions transport in two directions. Additionally, light irradiation as an external energy source can reduce the energy barriers to promote ions transport bidirectionally. The anomalous ion transport together with the robust nanoporous carbon structure may find applications in membrane filtration, water desalination, and fuel cell membranes.