Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanoparticles: When less is more in predicting performance

09.11.2012
A computational approach that makes processor-intensive first-principle calculations more manageable is now available to predict the structure of nano-alloy catalysts

Nanoparticles can be potent catalysts. Bimetallic nano-alloys of platinum and palladium, for example, can help to generate hydrogen fuel by promoting the electrochemical breakdown of water.

Identifying the most active nano-alloy for such a task, however, remains a challenge; catalytic performance relates directly to particle structure, and experiments to establish the atomic arrangement of such small particles are difficult to perform. Predicting stable nano-alloy structures is now possible using a computational approach developed by Teck Leong Tan at the A*STAR Institute of High Performance Computing and his co-workers1.

Their technique can also identify ways in which the nanoparticle’s atomic structure could be tuned to improve catalytic performance.

The challenge with calculating nano-alloy structure and properties from first principles is the computational processing power it requires, says Tan. For their study, he and his co-workers considered a 55-atom nano-alloy particle, each site in the structure filled by either a palladium or a platinum atom. “There are millions of possible alloy configurations, so it would be computationally intractable to do a direct search using first-principles calculations,” Tan explains.

To make the process manageable, the researchers conceptually broke the nanoparticle down into small geometric subunits, or clusters. From first principle calculations on a set of around 100 different alloy structures, each consisting of 30 or so clusters, they generated a reliable model of alloy behavior using an approach called cluster expansion. From this model, they calculated whole-nanoparticle properties. “The model is used to rapidly search through the huge configuration space for low-energy states,” says Tan. These low-energy states represent the stable alloy configurations that should exist experimentally (see image).

Using their calculated stable structures, Tan and his co-workers then predicted how different atomic conformations affect a particle’s performance as a catalyst. As a model reaction, the researchers examined the hydrogen evolution reaction, the electrochemical generation of hydrogen gas. The results suggest that particle catalytic activity will increase as more palladium is added, because this alloy improves hydrogen binding at various adsorption sites on the nanoparticle surface — useful information for guiding the synthesis of new nanocatalysts.

The approach should be widely applicable for nanoparticle research, notes Tan. “The cluster expansion method can generally be applied to any alloy systems where structures and stabilities are of interest,” he says. Tan next plans to investigate the impact of molecules adsorbed onto a catalyst’s surface. “The presence of adsorbed molecules often leads to changes in alloy structures, thereby altering catalytic performance,” he says.

The A*STAR-affiliated researchers contributing to this research are from the Institute of High Performance Computing
Associated links
http://www.research.a-star.edu.sg/research/6581
Journal information
Tan, T. L., Wang, L. -L., Johnson, D. D. & Bai, K. A comprehensive search for stable Pt−Pd nanoalloy configurations and their use as tunable catalysts. Nano Letters 12, 4875–4880 (2012)

A*STAR Research | Research asia research news
Further information:
http://www.research.a-star.edu.sg/research/6581
http://www.researchsea.com

More articles from Information Technology:

nachricht Drones learn to navigate autonomously by imitating cars and bicycles
23.01.2018 | Universität Zürich

nachricht Cloud technology: Dynamic certificates make cloud service providers more secure
15.01.2018 | Technische Universität München

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Optical Nanoscope Allows Imaging of Quantum Dots

Physicists have developed a technique based on optical microscopy that can be used to create images of atoms on the nanoscale. In particular, the new method allows the imaging of quantum dots in a semiconductor chip. Together with colleagues from the University of Bochum, scientists from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute reported the findings in the journal Nature Photonics.

Microscopes allow us to see structures that are otherwise invisible to the human eye. However, conventional optical microscopes cannot be used to image...

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Rutgers scientists discover 'Legos of life'

23.01.2018 | Life Sciences

Seabed mining could destroy ecosystems

23.01.2018 | Earth Sciences

Transportable laser

23.01.2018 | Physics and Astronomy

VideoLinks Science & Research
Overview of more VideoLinks >>>