Scientists from the U.S. Department of Energy’s (DOE) Argonne National Laboratory and Ames National Laboratory report a faster, more energy-efficient way to manufacture propylene than the process currently used.

Converting propane into propylene typically involves a metal catalyst like chromium or platinum on a support material, such as aluminum oxide or silicon dioxide. The catalyst speeds up the reaction. However, it also necessitates high operating temperatures and energy use.

In a collaborative project, scientists from Argonne and Ames found that zirconium combined with silicon nitride enhances the catalytic conversion of propane gas to propylene. It does so in a way that is faster-reacting and less toxic and uses less energy than other nonprecious metals, like chromium. It is also less expensive than precious metal catalysts like platinum.

This discovery also reveals a way to reduce the temperature of the catalytic process. In turn, this reduces the amount of carbon dioxide released. Carbon dioxide accounts for almost 80% of greenhouse gas emissions in the United States.

Additionally, this research gives a glimpse into the reactivity achievable with other low-cost metals in the catalytic conversion of propane into propylene.

For some time, Argonne chemists David Kaphan and Max Delferro have been systematically studying how nontraditional surfaces influence and promote catalysis.

As lead researchers on this study, they wanted to understand how a nontraditional metal catalyst on a nontraditional type of support compares with traditionally used materials during the catalytic conversion of propane.

Catalyst support materials typically have high surface areas and help to distribute catalysts. They can also play an important role in promoting catalysis, as shown in this study.

The research team found that a zirconium catalyst on a silicon nitride support yielded significantly more active catalysis for the conversion of propane into propylene. Conversely, this was not the case with the silica support.

They also found that the silicon nitride support enabled catalysis in a way that’s faster and more energy efficient than with traditional metals on silica. As a catalyst support, silicon nitride can enhance chemical reactions on the surface of metals relative to more traditionally used oxides.

The scientists achieved catalytic conversion of propane at a temperature of 842 degrees F. This is slightly lower than the 1,022 degrees F typically required for catalysis using traditional materials.

Furthermore, when run at the same temperature as traditional catalysts for this transformation, the reaction rates were significantly faster than similar materials with oxide supports.

This discovery also offers proof that this concept can be generalized for other important reactions.

“This provides a window into nitride-supported metal reactivity. We see promise with the use of other transition metals where we can leverage this difference in the local environment of the nitride surface to enhance catalysis,” Kaphan said.

This research benefited from Argonne’s Advanced Photon Source (APS), a DOE Office of Science user facility. At beamline 10-BM, researchers used X-ray absorption spectroscopy to understand how the zirconium catalyst interaction with the nitride material differs from the oxide material.

Argonne researchers also collaborated with Frédéric Perras, a scientist at Ames National Laboratory, to gain a better understanding of the structure of the zirconium/silicon nitride catalyst. He used a dynamic nuclear polarization-enhanced nuclear magnetic resonance technique to analyze how silicon nitride reacts with metal sites.

“The composition on the surface of silicon nitride is largely unknown, which is what I found most exciting about this work,” said Perras, who is also an adjunct associate professor at Iowa State University.

The combination of material characterization techniques available at Argonne and Ames and the expertise of the people who worked on this paper is what contributed to the success of this experiment, according to Delferro.

“One person cannot do everything. This is really a team effort, and everyone brought their expertise to the table to achieve this goal,” he said.

A paper on the study was published in the Journal of the American Chemical Society. In addition to Delferro, Kaphan and Perras, authors include Joshua DeMuth, Yu Lim Kim, Jacklyn Hall, Zoha Syed, Kaixi Deng, Magali Ferrandon, A. Jeremy Kropf and Liu Cong.

Support for the research came from DOE’s Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences, Catalysis Science program.

A new study in the Journal of the American Heart Association, led by Lindsay Rosman, PhD,assistant professor of medicine in the division of cardiology at the University of North Carolina School of Medicine, is the first to show that wearable devices, such as smart watches, can significantly amplify anxiety and increase healthcare use in patients with Afib.

The study included 172 patients from UNC Health with a prior diagnosis of Afib who completed a survey and had their information linked to electronic health records. About half of the study sample had a wearable device and their data was compared to individuals without a wearable device. Rosman and her team found that patients with Afib who use wearables are more likely to be preoccupied with their heart symptoms, report concerns about their AFib treatment, and use healthcare resources compared to Afib patients without these devices. Providers and healthcare clinics were also impacted, as wearable users were more likely to call the clinic and send messages to their healthcare providers than individuals who did not have a device.

Also, 1 in 5 AFib patients who used wearables in this study experienced intense fear and anxiety in response to irregular rhythm notifications from their device. And a similar proportion (20%) routinely contacted their doctors when ECG results were abnormal or indicative of possible AFib. But it’s unclear if they actually needed to see a doctor, due to the alerts from their devices. It’s also unclear if the reported anxiety contributed to the worsening of symptoms, although anxiety has been a well-documented contributing factor to various conditions, including AFib.

“Given the significant increase in use of wearable devices in this patient group (and the population in general),” said Rosman, “we believe prospective studies and randomized trials are needed to understand the net effects of wearables — including their alerts — on patients’ healthcare use and psychological well-being, as well as the downstream effects on providers, hospitals, and health systems.”

The team has pioneered a new method to extract purified active materials from battery waste as detailed in the journal Nature Communications on July 24. Their findings have the potential to facilitate the effective separation and recycling of valuable battery materials at a minimal fee, contributing to a greener production of electric vehicles (EVs).

“With the surge in battery use, particularly in EVs, the need for developing sustainable recycling methods is pressing,” Tour said.

Conventional recycling techniques typically involve breaking down battery materials into their elemental forms through energy-intensive thermal or chemical processes that are costly and have significant environmental impacts.

The team proposed that magnetic properties could facilitate the separation and purification of spent battery materials.

Their innovation uses a method known as solvent-free flash Joule heating (FJH). This technique devised by Tour involves passing a current through a moderately resistive material to rapidly heat and transform it into other substances.

Using FJH, the researchers heated battery waste to 2,500 Kelvin within seconds, creating unique features with magnetic shells and stable core structures. The magnetic separation allowed for efficient purification.

During the process, the cobalt-based battery cathodes — typically used in EVs and associated with high financial, environmental and social costs — unexpectedly showed magnetism in the outer spinel cobalt oxide layers, allowing for easy separation.

The researchers’ approach resulted in a high battery metal recovery yield of 98% with the value of battery structure maintained.

“Notably, the metal impurities were significantly reduced after separation while preserving the structure and functionality of the materials,” Tour said. “The bulk structure of battery materials remains stable and is ready to be reconstituted into new cathodes.”

Rice graduate students Weiyin Chen and Jinhang Chen as well as postdoctoral researcher and Rice Academy Junior Fellow Yi Cheng are the co-lead authors of the study.

The co-authors include research administrator of materials science and nanoengineering Ksenia Bets; former postdoctoral researcher and now academic visitor in the Tour lab Rodrigo Salvatierra; postdoctoral researcher Bing Deng; applied physics graduate students Chang Ge, Duy Luong and Emily McHugh; Rice alumni John Li and Zicheng Wang; chemistry research scientist Carter Kittrell; research scientist of materials science and nanoengineering Guanhui Gao; assistant professor of materials science and nanoengineering Yimo Han; and the Karl F. Hasselmann Professor of Engineering and professor of materials science and nanoengineering Boris Yakobson.

The study was supported by the Air Force Office of Scientific Research, U.S. Army Corps of Engineers ERDC and Rice Academy Fellowship.