Scientists at the University of NSW (UNSW) have made a fundamental discovery in materials science that has potential applications for water filtration and energy storage. This is focused on the “wonder material,” graphene oxide (GO).
Imagine scattering a big box of LEGO bricks on your living room floor. A few days later you come back, and they have magically formed nicely organised piles by themselves. A team of researchers at UNSW have observed something like this, but under a very powerful microscope and looking at atoms.
The chemical compound graphene oxide is made up of a single layer of carbon atoms with oxygen atoms attached. Naturally, the oxygen atoms are attached to the graphene in a rather chaotic way. But at elevated temperatures, the oxygen atoms form more organised structures – as it turns out, by themselves.
This process of “self-organisation” drastically improves various properties of GO, such as its electrical conductivity.
Graphene oxide is an extremely thin form of carbon that has shown promise as a material for filters that improve water quality and moisture control. This new discovery further creates possible applications in energy storage, optoelectronics, biotechnology and highly precise water filtration.
For the past 10 years, researchers have assumed that this phenomenon existed but they could only demonstrate it in computational simulations. The pioneering research led by Dr Rakesh Joshi at UNSW – published in Materials Today – successfully observed it for the first time in real life, using electron microscopy.
While common microscopes use light to create a magnified image, electron microscopes use electrons. With this type of microscope, it is possible to observe single atoms, by magnifying what you’re looking at by a factor of 1 million.
First author Tobias Foller, a PhD student in Joshi’s group, first read about the temperature method that enhances the properties of GO without changing the chemical structure in a paper by researchers from Massachusetts Institute of Technology (MIT).
“I was immediately fascinated,” Foller said. “Reading more, I noticed a significant amount of research was using this phenomenon to fine-tune the properties of GO for a wide range of possible applications.
“But none of these studies showed a direct observation of the mechanism – they assumed it was driving these enhancements, but didn’t actually demonstrate it.”
Foller look into the matter more closely.
As the first results began to form, the first author on the MIT paper, Dr Priyank Kumar, joined UNSW as a Scientia lecturer in Engineering, to see the experimental discovery through to the end.
“I was thrilled to see the first results that could finally give direct evidence to our previous work,” Kumar said, who also collaborated on the study published this month.
A range of applications
“Now that we understand this mechanism, and have seen how it actually plays out in real life, we can control the properties of GO more precisely,” Joshi said.
“This all adds up to a key finding that gives us a deeper understanding of the properties of GO – and it might play a key role in bringing it a step closer to real-world applications such as sustainable water filtration, hydrogen generation and many more.”
The study in Materials Today is co-authored by scientists in electron microscopy, including UNSW associate professor Shery Chang and Gwan-Hyoung Lee from Seoul National University. UNSW’s hydrogen generation experts Professor Rose Amal and Dr Rahman Daiyan were also contributing authors.