Published October 25, 2021
By Kimberly Mann Bruch, SDSC Communications
Hydrogen peroxide, often used as a disinfectant, serves as a precursor for many organic compounds. Recently, computational materials scientists at The University of Texas Austin (UT Austin) investigated a novel synthetic approach where oxygen molecules react with water and electrons with the help of a catalyst, such as a cobalt atom bound to four nitrogen atoms and embedded in a thin layer of carbon (Co-N4-C), to form hydrogen peroxide. However, the scientists were puzzled about how and why the reaction produced hydrogen peroxide (H2O2) rather than hydroxide (OH-), which was expected due to its lower energy. To answer this question, they used supercomputing resources to simulate the reaction at an atomic scale.
The UT Austin scientists used Comet at the San Diego Supercomputer Center (SDSC) at UC San Diego and Stampede2 at the Texas Advanced Computing Center (TACC) at UT Austin, to detail how oxygen molecules react with water and electrons to form hydrogen peroxide on the catalyst.
Yuanyue Liu, an assistant professor of materials science and engineering, and Xunhua Zhao, a postdoctoral researcher, recently published their study results in the Journal of American Chemical Society.
Prior to these simulations, which were run on Comet and Stampede2 thanks to allocations from the National Science Foundation Extreme Science and Engineering Discovery Environment (XSEDE), there was limited understanding about why some catalysts yield more hydrogen peroxide than hydroxide, due to the lack of an effective tool to simulate the kinetics.
“XSEDE provided computational resources without which we would not able to do our research,” Zhao said. “Using Comet and Stampede2 to simulate this reaction, we found that bond breaking to yield hydrogen peroxide can have a lower energy barrier than the bond breaking to yield hydroxide, despite that the hydroxide has a lower energy than the hydrogen peroxide.”
“Moreover, we explained why the yield of hydrogen peroxide increases with decreasing electrode potential,” Liu said. “There are two types of oxygen in the reaction, and depending on which one first gets hydrogen from water, you may obtain different products — decreasing the electrode potential pushes the water closer to the oxygen and that will give us hydrogen peroxide.”
Why It’s Important and What’s Next
Liu and Zhao’s findings have helped the materials science community further understand this important fundamental process; however, there is much work to be done.
“While our research uncovers how hydrogen peroxide is selectively produced, we continue to work on making our simulations less computationally expensive,” Liu said. “We are also working on applying this model to other electrochemical systems.”
How Supercomputers Helped
“We used XSEDE resources to first develop an advanced first principles model for effective calculations of the electrochemical kinetics at the solid-water interface,” Liu said. “Then, we used Comet and Stampede2 to simulate the pathways of forming hydrogen peroxide and hydroxide on the Co-N4-C catalyst, and how these pathways vary with the applied electrode potential — this allowed us to understand what makes one product more favorable than the other, and how to tune the preference.”
Zhao and Liu said that while they ran into a few code compilation problems during their study, SDSC support was helpful in assisting with solutions.
“We look forward to working on Expanse at SDSC for our next set of simulations that will help us continue developing and applying atomistic modelling methods to understand, design, and discover materials for electronics and energy applications,” Liu said.
This work was supported by the National Science Foundation (award nos. 1900039 and 2029442), the Welch Foundation (F-1959-20180324), ACS PRF (60934-DNI6) and the Department of Energy (DE-EE0007651). This work used computational resources at National Renewable Energy Lab, XSEDE (allocation TG-CHE190065), the Center for Nanoscale Materials at Argonne National Laboratory and the Center for Functional Nanomaterials at Brookhaven National Laboratory.
About SDSC
The San Diego Supercomputer Center (SDSC) is a leader and pioneer in high-performance and data-intensive computing, providing cyberinfrastructure resources, services and expertise to the national research community, academia and industry. Located on the UC San Diego campus, SDSC supports hundreds of multidisciplinary programs spanning a wide variety of domains, from astrophysics and earth sciences to disease research and drug discovery. SDSC’s newest National Science Foundation-funded supercomputer, Expanse, supports SDSC’s theme of “Computing without Boundaries” with a data-centric architecture, public cloud integration and state-of-the art GPUs for incorporating experimental facilities and edge computing.
About TACC
The Texas Advanced Computing Center (TACC) at The University of Texas at Austin is one of the leading supercomputing centers in the world. TACC's mission is to enable discoveries that advance science and society through the application of advanced computing technologies. The center operates two of the most powerful university supercomputers in the U.S. — Frontera and Stampede2 — and more than a dozen advanced computing systems in total. Tens of thousands of scientists and students use TACC's supercomputers each year to answer complex questions in every field of science. TACC staff also encourage, educate, and train the next generation of researchers, empowering them to make discoveries that change the world. Learn more.
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