Although they may not be huge, Nanodiamonds can help address one of humanity’s most pressing problems: Climate change.
Hydrogen is a clean-burning fuel that leaves no other than water after consumption. Although hydrogen is seen as a means to a zero-carbon future in many countries, it will be more expensive to produce than it is currently.
In a recent study published in Nature Energy, researchers led by Kyoto University’s Institute for Integrated Cell-Material Sciences (iCeMS) describe how nanodiamond-reinforced composite membranes can purify hydrogen from its humid mixtures, making the hydrogen generation processes vastly more efficient and cost-effective.
“There are many scalable methods to make hydrogen. However, hydrogen is generally found in humid mixtures, so that purification can be a challenge,” said Professor Easan Savannah, the leader of the iCeMS project. “Membrane technology permits energy-efficient, economic separation processes. Savannah said it is essential to use suitable membrane materials to make it work.
Graphene oxide, a water-soluble graphite derivative, can be combined to make a membrane that can be used in hydrogen purification. These filters allow hydrogen gas to pass through easily, while larger molecules can get stuck.
In humid conditions, hydrogen can be separated from CO 2 or O 2. Negatively charged GO sheets repel one another. The negatively charged sheets become more repellent when exposed to humidity. Water molecules can build up between the sheets and eventually cause the membrane to dissolve.
The research was co-supervised by Dr. Behnam Galei. He explained that nanodiamonds could be added to the GO sheets to solve the humidity-induced disintegration problem. “Positively charged nanodiamonds can cancel the membrane’s adverse repelling effects, making the GO sheets compacter and more water-resistant.
Savannah says, “In our collaboration with Avec Dr. RyujiIgarashi of QST, we were able to access nanodiamonds that have well-defined sizes functionality, and without which the research wouldn’t have been possible.” Importantly, Igarashi’s team has a patent technology that will allow them to scale up the production of nanodiamonds at a low cost.
Savannah believes that nanodiamonds can be used for more than hydrogen production. Humidity control is essential in many other areas, such as pharmaceuticals, semiconductors, and battery production. The use of membrane technology to remove humidity could revolutionize air conditioning. Air conditioners are one of the most inefficient methods of cooling. The large amount of electricity they use to run removes humidity. This can lead to more CO 2 emissions and a vicious global warming cycle.
Japan is committed to a zero-carbon future. To support joint ventures between prominent industry players and entrepreneurs that bring new technologies onto the market, it has created a US$20 million Green Innovation Fund.