A successful, sustainable catalyst for ethanol dehydrogenation
Ethanol is an alcohol used in a vast number of industrial and household applications. When dehydrogenated—in this case, stripped of some of its hydrogen atoms—it yields another important compound: acetaldehyde, which is used to make resins, dyes, perfumes and synthetic flavors, among many other products. But currently available catalysts for ethanol dehydrogenation suffer from deactivation, poor performance over time and unwanted side reactions.
A good catalyst is essential for a reaction because it can improve production, allowing a product to be made more cheaply and quickly. At the U.S. Department of Energy's (DOE) Brookhaven National Laboratory, a collaboration between Brookhaven researchers and international scientists has developed a catalyst that facilitates ethanol dehydrogenation more quickly and with less waste than other catalysts, including metals such as copper and nickel. These catalysts suffer from several major issues, including a tendency to clump together or break down the ethanol too much.
"Our catalyst solves an important problem in chemistry because it completes a selective dehydrogenation: Instead of stripping away all of the hydrogen atoms, it removes just the ones necessary," said chemist Anatoly Frenkel, who holds a joint appointment with Brookhaven and Stony Brook University and co-led the paper on the work, which appears in the journal Angewandte Chemie.
In addition to its promising performance, this ethanol-based catalytic system is more sustainable than other methods used to produce acetaldehyde, which involve petrochemicals. Ethanol, on the other hand, can be produced from biomass, such as food waste, crop residues and forestry byproducts.
Three's a catalyst
The system developed here is unusual for thermal catalysis, in which heat assists the process, because it consists of three metals—platinum, chromium and silver—instead of just two or one. Rather than being dispersed in the silver as single atoms, the platinum and chromium atoms pair up in dumbbell-like structures, with the sea of silver acting as a bulk host material.
"Systems like this one, in which two different metals form a 'dimer' structure like our dumbbells, supported by a bulk third metal, tend to have broader functionality and greater stability—each metal takes on a different key role," Frenkel said. "But they have not been well explored, and detecting the dimers and studying those roles is exceedingly difficult."
To understand the system's behavior, the group used a variety of methods. These included theoretical modeling, microscopy and X-ray techniques at two synchrotron facilities: Brookhaven's National Synchrotron Light Source II (NSLS-II), a DOE Office of Science user facility, and the MAX IV synchrotron laboratory in Sweden.
Theory guides experiment
The group began its investigation with crucial theoretical work, which it used to guide the design of the catalyst. According to its calculations, the platinum-chromium-silver system would achieve selective dehydrogenation.
"Prior quantum chemical calculations and surface science experiments by our collaborators showed that platinum-chromium pairs form preferentially in silver and exhibit electronic structures distinct from isolated platinum and chromium sites, enabling unique surface chemistry," said Jason Weaver, a chemist at the University of Florida and the paper's first author.
"These insights motivated us to test whether trimetallic platinum-chromium-silver alloys could sustain ethanol dehydrogenation under practical reaction conditions and to directly identify the presence and catalytic role of platinum-chromium pair sites."
The group turned to a series of experiments, using samples prepared by Jürgen Biener, a scientist at DOE's Lawrence Livermore National Laboratory and a co-author of the paper.
At the Quick X-ray Absorption and Scattering (QAS) beamline at NSLS-II, members of the group used an X-ray method that provides information about the bulk of the sample. This technique, known as X-ray absorption fine structure (XAFS), provided precise measurements of the behavior of the platinum, chromium and silver atoms, as well as their respective neighboring atoms.
The data, which were analyzed by Shuting Xiang, a graduate student in Stony Brook's Materials Science and Chemical Engineering Department and the paper's second author, revealed that the platinum and chromium were indeed paired.
Having proven that the platinum-chromium dumbbells were present in the sample's bulk, the group needed to show that they existed on the surface. They shipped the samples to MAX IV, where they were studied by Weaver and two colleagues, Lund University's Jan Knudsen and Malmö University's Lindsay Merte, using a type of XAFS method that is sensitive to surface details and can be used under real-time reaction conditions. This work helped them understand the local environment and behavior of each metal, a necessary step before they could piece together a complete picture of the system.
"These surface studies were critical for connecting all components of our work," Frenkel said. "This was a very important and novel aspect of the study, as most experimental methods focus on the bulk of the catalyst, while the chemical transformations that we investigated occur on the surface."
Importantly, the work at MAX IV also included another technique, ambient-pressure X-ray photoelectron spectroscopy (AP-XPS). This is also a surface-sensitive technique, but it allows the sample to be studied under active conditions and is therefore a useful tool for understanding the full structure-function relationship of chemical reactions. In this case, the AP-XPS work confirmed that the only samples that performed well were those that contained the platinum-chromium dumbbells.
"AP-XPS allows us to look at reacting molecules in the gas and on the surface at the same time and relate this to what the metals are doing," Merte said. "Combining this with the local bonding information from surface-sensitive XAFS gives a really complete picture of the state of the catalyst and how this affects its performance."
The experimental work also included reactivity studies and scanning transmission electron microscopy (STEM) at Brookhaven's Center for Functional Nanomaterials, another DOE Office of Science user facility. The STEM work provided additional information on the distribution and local atomic environment of the platinum and chromium atoms within the silver host.
When reconciled, the full suite of approaches directly links the platinum-chromium dimers, embedded in silver, to the enhanced activity of the platinum-chromium-silver alloy compared with two-metal alloys.
"The success of this study shows that some scientific problems can only be solved when you bring together theorists and experimentalists, applying multiple approaches in a coordinated way," Frenkel said.
Publication details
Jason F. Weaver et al, Self‐Stabilized Heterometallic Pair Sites for Selective Ethanol Dehydrogenation on Pt–Cr–Ag Alloy Catalysts, Angewandte Chemie International Edition (2025). DOI: 10.1002/anie.202513844
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Citation: A successful, sustainable catalyst for ethanol dehydrogenation (2026, July 29) retrieved 30 July 2026 from https://phys.org/news/2026-07-successful-sustainable-catalyst-ethanol-dehydrogenation.html
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