Science & Technology

Simulations show that iron catalyzes the corrosion of “inert” carbon dioxide

Iron (blue) can react with trace amounts of water to produce corrosive chemicals, even though it is immersed in the “inactive” supercritical fluid of carbon dioxide. Atomic simulations performed at Rice University show how this reaction occurs. Credit: Evgeni Penev / Rice University

Theoretically, iron that rusts in water should not corrode in contact with the “inactive” supercritical fluid of carbon dioxide. But that’s right.

I do not know why Materials scientist To date, the Rice University team has a theory that can contribute to new strategies for protecting iron from the environment.

George R from Rice University. Through atomic-level simulations, Brown School of Engineering material theorist Boris Yakobson and his colleagues have discovered that iron itself is involved in its own corrosion when exposed to supercritical CO.2 (SCO2) And trace amounts of water by promoting the formation of reactive species in the fluid that returns to attack it.

Their study was published in the Cell Press Journal Matter, They are graphene Hexagonal boron nitride Can be used as a barrier between Iron atom And sCO reactive elements2..

Rice graduate student Qin-Kun Li and research scientist Alex Kutana are co-lead authors of this paper. Evgeni Penev, Professor of Rice Assistant Research, is a co-author.

Supercritical fluid is a material of temperature and pressure that keeps the phases roughly. For example, not everything is liquid, but not all gas yet. Characteristics of sCO2 According to researchers, it is “essentially inert”, non-corrosive and low cost, making it an ideal hydraulic fluid.

Jacobson, a professor of materials science and nanoengineering at Carl F. Hasselmann and a professor of chemistry, said: “Iron has long been a pillar of infrastructure, but it is only now that we have an atomistic understanding of how iron corrodes.”

Rice Lab’s simulation reveals the details of the devil. Previous studies have attributed corrosion to the presence of large amounts of water and other pollutants in superfluidity, but this is not always the case, Jacobson said.

“Water as a major impurity in sCO2Provides a hydrogen bond network that causes an interfacial reaction with CO2 And like other impurities Nitrous oxide It forms corrosive acids that are harmful to iron. “

Simulations have also shown that iron itself acts as a catalyst, lowering the reaction energy barrier at the interface between iron and sCO.2Finally, it leads to the formation of hosts for corrosive species such as oxygen, hydroxides, carboxylic acids and nitrites.

For researchers, this study demonstrates the power of theoretical modeling to solve complex chemical problems. In this case, predict the thermodynamic reaction and iron And sCO2.. They also showed that if the superfluidity contained trace amounts of water, all bets would be invalidated and corrosion would accelerate.

The team creates a supercritical carbon dioxide turbomachine for concentrated solar power plants

For more information:
Qin-Kun Li et al, Iron Corrosion in “Inert” Supercritical CO2, Insights in Ab initio Dynamics: Importance of Impurities, Matter (2022). DOI: 10.1016 / j.matt.2021.12.019

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Rice University

Quote: Simulations show that iron catalyzes the corrosion of “inert” carbon dioxide (January 21, 2022).

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Simulations show that iron catalyzes the corrosion of “inert” carbon dioxide Simulations show that iron catalyzes the corrosion of “inert” carbon dioxide

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