The research team of Professor Wu Heng’an of the University of Science and Technology of China and the research team of Wang Huanting, a professor at Monash University in Australia, prepared a new type of nano-rectifier device based on metal-organic framework (MOF) materials, which realized the bidirectional rapid rectification transport of metal ions and protons for the first time, and provided new design ideas for the development of new bionic nano-rectifier devices and nano-energy traps. The research results were recently published in Science Advances.
Metal-organic framework (MOF) two-way rapid rectifier transport mechanism of ions and protons in sub-nanometer channels Courtesy of the University of Science and Technology of China
Rectification refers to the one-way transmission of substances in a channel. Efficient ion integrity channel is the structural basis for the regulation of various physiological functions of the organism, for example, the potassium ion channel on the surface of the biofilm can realize the rectification of ions and protons in the opposite direction to ensure the balance of electrolytes and pH on both sides of the membrane and maintain the normal progress of various life activities.
In addition, the ion whole flow channel has a wide range of application prospects in engineering and technical practices such as clean energy conversion and storage, and acid solution recovery for sustainable mining.
Inspired by bioion channels, various nanoflow modules/membranes with (sub)nanometer sizes have been reported to enable biomimetic ion transport, ion separation, and energy capture.
For example, scientists have successfully achieved unidirectional rectification of bioion-like ion channels based on materials such as carbon nanotubes, graphene, polymers, and metal-organic frameworks (MOFs).
However, to date, how to achieve bidirectional commutation transport of metal ions and protons in a nanochannel (device) at the same time is still a research gap in this field.
In this study, Wang Huanting’s research team designed and prepared an asymmetric nanochannel structure composed of a metal-organic framework (MOF) and polyethylene terephthalate (PET), which successfully realized the rapid bidirectional commutation of metal ions and protons.
The computational mechanics team of the University of Science and Technology of China developed a theoretical model of nano-limit mass transfer, analyzed the rectified transport phenomenon of ions and protons in asymmetric nanochanns, and revealed the two-way rapid rectification transport mechanism of metal ions and protons in the limited space.
Theoretical calculations found that the transport of metal ions in the confined space was regulated by the concentration gradient, while the conduction of protons was determined by the regularly arranged water chain structure, and the different transport mechanisms of the two particles led to the bidirectional rectification characteristics of the nanochannel.
It is worth mentioning that the polarity sites in the metal-organic framework (MOF) sub-nanometer channel form a synergistic hydrogen bond network with water molecules, which further improves the directional migration ability of protons, and even higher than the proton conduction ability of one-dimensional restricted water chains in carbon nanotubes of the same size, with the characteristics of rapid rectifier transmission.
The bidirectional rapid rectifier transport mechanism of metal ions and protons in the confined space proposed in the study provides a new idea for the structural design of artificial ion channels, which is expected to promote the further development of high-throughput selective membrane technology.
The reviewers believe that the two-way rectification mechanism of ions and protons proposed in this study is “enlightening, interesting and meticulous” and “opens up new directions for the real application of metal-organic framework materials through experimentation and theory and mutual cooperation”. (Source: China Science Daily Wang Min)
Related paper information:https://doi.org/10.1126/sciadv.abl5070