A breakthrough in research could transform clean energy technology

By some estimates, the amount of solar energy that reaches Earth’s surface in one year is greater than the sum of all the energy we could ever produce from non-renewable sources. The technology needed to convert sunlight into electricity has developed rapidly, but inefficiencies in the storage and distribution of that power have remained a major problem, making solar power on a large scale impractical. However, a breakthrough by researchers from UVA’s College and Graduate School of Arts & Sciences, the California Institute of Technology and the Argonne National Laboratory of the U.S. Department of Energy, Lawrence Berkeley National Laboratory and Brookhaven National Laboratory would be a critical obstacle to the process. can take away, a discovery that represents a giant step towards a clean energy future.

One way to harness solar energy is to use solar electricity to split water molecules into oxygen and hydrogen. The hydrogen produced by the process is stored as fuel, in a form that can be transferred from one place to another and used to generate power on demand. A catalyst is needed to split water molecules into their constituent parts, but the catalytic materials currently used in the process, also known as the oxygen evolution reaction, are not efficient enough to make the process practical.

Using an innovative chemical strategy developed at UVA, a team of researchers led by chemistry professors Sen Zhang and T. Brent Gunnoe has produced a new form of catalyst using the elements cobalt and titanium. The advantage of these elements is that they are much more abundant in nature than other commonly used catalytic materials containing precious metals, such as iridium or ruthenium.

“The new process involves creating active catalytic sites at the atomic level on the surface of titanium oxide nanocrystals, a technique that produces a durable catalytic material and one that is better at triggering the oxygen evolution reaction.” Zhang said. “New approaches to efficient reaction catalysts for oxygen generation and a better fundamental understanding of them are essential for a possible transition to scale use of solar renewable energy. This work is a perfect example of how catalyst efficiency for clean energy technology can be optimized by tailoring nanomaterials to atomic scale. . “

According to Gunnoe, “This innovation, focused on the performance of the Zhang laboratory, represents a new method to improve and understand catalytic materials with a resulting effort that includes the integration of advanced material synthesis, atomic-level characterization and quantum mechanics theory.”

Several years ago, UVA joined the MAXNET Energy consortium, consisting of eight Max Planck Institutes (Germany), UVA and Cardiff University (UK), which brought together international collaborative efforts focused on electrocatalytic water oxidation. MAXNET Energy was the seed for the current joint venture. efforts of my group and the Zhang lab, which has been and continues to be a fruitful and productive collaboration, ”said Gunnoe.

With the help of the Argonne National Laboratory and Lawrence Berkeley National Laboratory and their state-of-the-art user facilities for synchrotron X-ray absorption spectroscopy, which uses radiation to examine the structure of matter at the atomic level, the research team found that the catalyst has a well-defined surface structure that allows them to can clearly see how the catalyst evolves in the interval of the oxygen evolution reaction and accurately evaluate its performance.

“The work utilized X-ray beams from the Advanced Photon Source and the Advanced Light Source, including part of a ‘fast-access’ program reserved for a rapid feedback loop to explore emerging or urgent scientific ideas,” said Argonne X radiation physicist Hua Zhou, a co-author of the paper. “We are very pleased that both national scientific user facilities can make a substantial contribution to such smart and tidy water splitting work that will represent a leap forward for clean energy technologies.”

Both the Advanced Photon Source and Advanced Light Source are user facilities of the U.S. Department of Energy (DOE) Office of Science, located at DOE’s Argonne National Laboratory and Lawrence Berkeley National Laboratory, respectively.

Additionally, using newly developed quantum mechanical methods, researchers at Caltech were able to accurately predict the rate of oxygen production induced by the catalyst, providing the team with a detailed understanding of the chemical mechanism of the reaction.

“We have been developing new quantum mechanical techniques for over five years to understand the reaction mechanism of oxygen evolution, but in all previous studies we could not be sure of the exact catalyst structure. Zhang’s catalyst has a well-defined atomic structure, and we discover that our theoretical results are essentially in exact agreement with experimental observations, ”said William A. Goddard III, professor of chemistry, materials science and applied physics at Caltech and one of the main researchers on the project.“ This provides the first strong experimental validation of our new theoretical methods, which we can now use to predict even better catalysts that can be synthesized and tested. This is an important milestone towards global clean energy. “

“This work is a great example of the team effort of UVA and other researchers to work on clean energy and the exciting discoveries that come from these interdisciplinary collaborations,” said Jill Venton, chair of UVA’s Chemistry Department.