The precious metal platinum has long been prized for its ability to spur key chemical reactions in a process called catalysis, but at more than $1,000 an ounce, its high price is a limiting factor for applications like fuel cells, which rely on the metal.
In a search for an inexpensive alternative, a team including researchers from the Department of Energy's Oak Ridge National Laboratory turned to carbon, one of the most abundant elements. Led by Stanford University's Hongjie Dai, the team developed a multi-walled carbon nanotube complex that consists of cylindrical sheets of carbon.
Once the outer wall of the complex was partially "unzipped" with the addition of ammonia, the material was found to exhibit catalytic properties comparable to platinum. Although the researchers suspected that the complex's properties were due to added nitrogen and iron impurities, they couldn't verify the material's chemical behavior until ORNL microscopists imaged it on an atomic level.
"With conventional transmission electron microscopy, it is hard to identify elements," said team member Juan-Carlos Idrobo of ORNL. "Using a combination of imaging and spectroscopy in our scanning transmission electron microscope, the identification of the elements is straight-forward because the intensity of the nanoscale images tells you which element it is. The brighter the intensity, the heavier the element. Spectroscopy can then identify the specific element. "
ORNL microscopic analysis confirmed that the nitrogen and iron elements were indeed incorporated into the carbon structure, causing the observed catalytic properties similar to those of platinum. The next step for the team is to understand the relationship between the nitrogen and iron to determine whether the elements work together or independently.
The team's findings are published in Nature Nanotechnology as "An oxygen reduction electrocatalyst based on carbon nanotube–graphene complexes." Coauthors on the paper are ORNL's Stephen Pennycook and Juan-Carlos Idrobo, Vanderbilt University's Wu Zhou, Stanford's Yanguang Li, Hailiang Wang, Liming Xie and Yongye Liang, and Tsinghua University's Fei Wei.
Research was carried out in part at the Shared Equipment Research Facility (ShaRE), a user facility supported by the U.S. Department of Energy, Office of Science; and by the Materials Sciences and Engineering Division in DOE's Office of Basic Energy Sciences.
ORNL is managed by UT-Battelle for the Department of Energy's Office of Science. DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit http://science.energy.gov.
Morgan McCorkle | EurekAlert!
Beyond conventional solution-process for 2-D heterostructure
22.06.2018 | Science China Press
Graphene assembled film shows higher thermal conductivity than graphite film
22.06.2018 | Chalmers University of Technology
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
22.06.2018 | Materials Sciences
22.06.2018 | Earth Sciences
22.06.2018 | Life Sciences