By utilizing innovative in-situ spectroscopy methods, researchers at Binghamton University and Brookhaven Lab acquire fresh perspectives on catalytic oxidation.
Scientists at Binghamton University, in collaboration with the Center for Functional Nanomaterials (CFN), a DOE facility at Brookhaven National Laboratory, have conducted research to gain insight into how peroxides found on copper oxide surfaces promote hydrogen oxidation while hindering carbon monoxide oxidation, thus enabling the manipulation of oxidation reactions. Two innovative spectroscopy techniques that had not been employed in this manner before were utilized to facilitate the observation of these rapid changes. The findings of this study have been published in the Proceedings of the National Academy of Sciences (PNAS).

According to materials scientist Anibal Boscoboinik, copper is an extensively researched and significant surface in both catalysis and corrosion science. He emphasizes the critical role of copper in industrial mechanical parts, making it essential to comprehend its corrosion processes.

"I have always been fascinated by copper systems," shared Ashley Head, a materials scientist at CFN. "Their unique properties and reactions are truly remarkable and visually striking."

Having a deeper comprehension of oxide catalysts provides scientists with greater command over the chemical reactions they generate, which can lead to solutions for producing clean energy. One such catalyst is copper, which can form and transform methanol into valuable fuels. Thus, regulating the copper's oxygen levels and electron count is a crucial step toward ensuring efficient chemical reactions.

Following The Oxide As a Proxy


Chemical compounds known as peroxides consist of two oxygen atoms connected through shared electrons. Due to the relatively weak bond in peroxides, they are highly susceptible to structural changes caused by other chemicals, which results in their reactivity. Scientists conducted an experiment where they investigated the impact of different gases, such as oxygen (O2), hydrogen (H2), and carbon monoxide (CO), on the peroxide species formed during catalytic oxidation reactions on an oxidized copper surface (CuO). By doing so, they were able to modify the redox steps of these reactions.

Redox is a chemical process that involves reduction and oxidation. During this process, the reducing agent loses an electron while the oxidizing agent gains an electron. Researchers have discovered that peroxide species can significantly enhance CuO reducibility and favor H2 oxidation by forming a surface layer. However, this same layer of peroxide can also inhibit CuO reduction and suppress CO oxidation. The opposite effects of peroxide on these two oxidation reactions arise from its ability to modify the surface sites where the reactions occur.

By identifying bonding sites and studying their impact on oxidation, scientists can manipulate these gases to better control the reactions. However, to fine-tune these reactions, scientists needed a comprehensive understanding of the processes at play.

Opting For The Appropriate Equipment For The Task


The team emphasized the significance of investigating this reaction in situ due to the highly reactive nature of peroxides, resulting in rapid changes that are difficult to capture without the appropriate tools and surroundings. Being able to capture such a brief moment on the surface is crucial.

Previously, IR spectroscopy conducted in situ did not reveal any existence of peroxide species on copper surfaces. This method uses infrared radiation to examine how a material's chemical properties react under certain conditions by observing the way radiation is reflected or absorbed. However, in a recent experiment, scientists were able to distinguish different peroxide species with slight variations in their oxygen content, which would have been challenging to identify on a metal oxide surface.

Head reminisced about the thrill he experienced while researching the infrared spectra of peroxide species on a surface. He was thrilled to discover that there were very few published works on the topic. It was a thrilling experience to be able to differentiate between these species using a technique that is not commonly used for this kind of research.

While IR spectroscopy provided some insights, it wasn't adequate to establish certainty. Consequently, the research team resorted to another spectroscopy technique, namely ambient pressure X-ray Photoelectron Spectroscopy (XPS). This method employs X-rays with lower energy to displace electrons from the specimen. The energy levels of these electrons offer valuable information about the chemical attributes of atoms present in the specimen. The availability of both techniques via the CFN User Program facilitated the success of this study.

According to Boscoboinik, one of our primary sources of pride lies in the instruments we have and modified on-site. Our instruments are interlinked so that users can manipulate the sample in a regulated setting between these two techniques and analyze them in situ to obtain complementary information. Under normal circumstances, taking the sample out to use another instrument elsewhere may alter its surface due to a change in environment.

Guangwen Zhou, a professor at the Thomas J. Watson College of Engineering and Applied Science’s Department of Mechanical Engineering and the Materials Science program at Binghamton University, highlighted the exceptional qualities of CFN, not only in terms of its cutting-edge scientific facilities but also in terms of the opportunities it offers for training young researchers. According to Zhou, the students involved in the program have gained substantial knowledge and practical experience in the advanced microscopy and spectroscopy tools that are available at CFN.

This paper was produced through the joint effort of four Ph.D. students in Zhou's team: Yaguang Zhu and Jianyu Wang, who are the primary co-authors of this article, along with Shyam Patel and Chaoran Li. These scholars are at the outset of their professional journey, having recently completed their doctoral studies in 2022.

Findings Future


The outcomes of this investigation can have broader implications for various categories of reactions and catalysts apart from copper. The discoveries, methods, and procedures employed by researchers can potentially be incorporated into associated research. Metal oxides have immense usage as catalysts or constituents in catalysts. Adjusting the production of peroxide on different oxides may serve as a strategy to impede or boost surface reactions in different catalytic processes.

Head shared that he is engaged in various copper and copper oxide projects, which also involve converting carbon dioxide into methanol that can be utilized as a clean energy source. He further added that examining peroxides on the identical surface he uses holds the potential to have a significant influence on other initiatives that employ copper and different metal oxides.

The Brookhaven National Laboratory receives funding from the U.S. Department of Energy's Office of Science. This office is the primary sponsor of fundamental research in the physical sciences within the United States and is dedicated to resolving contemporary issues. For further details, please visit science.energy.gov.