A significant breakthrough in graphene studies
Chemists have made a remarkable advancement by controlling the movement of halide ions through a two-layer nanographene system by intentionally introducing defects. Their findings open up new possibilities for applications in areas such as water purification and sensor technologies.
Graphene is an incredibly thin, flexible, and durable material composed entirely of carbon. It consists of layers that are essentially a single layer of carbon atoms. To achieve a thickness equivalent to that of a human hair, one would need to stack thousands of these layers on top of one another.
Numerous researchers are deeply engaged in the study of graphene. The unique characteristics of this material hold the potential for innovative applications, particularly in the fields of electronics and energy technology.
Enabling Graphene to Allow Molecule Passage
Scientists are particularly interested in controlling the permeability of graphene to various substances. “Defects can be strategically introduced into the carbon lattice of graphene, creating tiny holes that allow gases to pass through,” explains Professor Frank Würthner from Julius-Maximilians-Universität (JMU) Würzburg, Germany.
While permeability for some substances, like halide ions (such as fluoride, chloride, and bromide), has not yet been observed, it remains a topic of fundamental scientific interest for various applications, including water desalination and the detection or purification of diverse mixtures, according to Professor Würthner.
Introducing Defects to Facilitate Ion Passage: Findings Published in Nature
For the first time, Frank Würthner’s research team has developed a model system featuring a defect that permits the halides fluoride, chloride, and bromide to pass through, while iodide is excluded. This was accomplished in a stable double layer formed by two nanographenes that enclose a cavity. The halide ions that enter this cavity are held there, allowing researchers to measure the time taken for their passage. Their research has been published in the journal Nature.
Chloride is a key component of common salt, prevalent in seawater, and plays a vital role in biological processes in all organisms. Dr. Kazutaka Shoyama, co-leader of the project, states, “Demonstrating high permeability for chloride through single-layer nanographene and selective halide binding in double-layer nanographene brings several applications within reach.” These potential applications include membrane technology for water filtration, artificial receptors, and chloride channels.
The Next Objective: Constructing Larger Nanographene Stacks
The Würzburg team aims to create larger stacks of their nanographenes to further investigate ion flow, thus exploring processes that resemble those occurring in biological ion channels.
This research was conducted at the Institute of Organic Chemistry and the Center for Nanosystems Chemistry at JMU, with funding provided by the German Research Foundation (DFG) through two grants for developing nanographenes with imide groups.
