Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Water-cleanup catalysts tackle biomass upgrading

27.06.2014

Rice University researchers register 4th 'volcano plot' for palladium-gold catalysts

Rice University chemical engineer Michael Wong has spent a decade amassing evidence that palladium-gold nanoparticles are excellent catalysts for cleaning polluted water, but even he was surprised at how well the particles converted biodiesel waste into valuable chemicals.


Rice University scientists (from left) Michael Wong, Zhun Zhao and James Clomburg discovered a palladium and gold nanocatalyst that is faster -- about 10 times faster -- at converting glycerol into high-value products than catalysts of either metal alone.

Credit: Jeff Fitlow/Rice University

Through dozens of studies, Wong's team focused on using the tiny metallic specks to break down carcinogenic and toxic compounds. But his latest study, which is available online and due for publication in an upcoming issue of the Royal Society of Chemistry's journal Chemical Science, examined whether palladium-gold nanocatalysts could convert glycerol, a waste byproduct of biodiesel production, into high-value chemicals.

In scientific parlance, the data from the study produced a "volcano plot," a graph with a sharp spike that depicts a "Goldilocks effect," a "just right" balance of palladium and gold that is faster -- about 10 times faster -- at converting glycerol than catalysts of either metal alone.

... more about:
»Palladium »biomass »catalysts »chemicals »glycerol »volcano

"We've now seen this volcano plot at least four times now, first with TCE, then with the dry cleaning contaminant 'perc,' and more recently with chloroform and nitrites," Wong said. "The remarkable thing is that the reaction, in each case, is very different."

In previous studies, the nanocatalysts were used in reduction reactions, chemical processes marked by the addition of hydrogen. In the latest tests on glycerol conversion, the nanocatalysts spurred an oxidation reaction, which involves adding oxygen.

"Oxidation and reduction aren't just dissimilar; they're often thought of as being in opposite directions," Wong said.

In chemistry, the role of the catalyst is much like that of a matchmaker; catalysts cause other compounds to react with one another, often by bringing them into close proximity, but the catalysts themselves don't take part in the reaction. Catalysts often speed up reactions that would otherwise happen too slowly, and drugmakers and chemical companies use catalysts to improve the efficiency of their chemical processing. The global market for industrial catalysts is projected to top $19 billion by 2016.

Palladium and gold -- and mixtures of the two -- have long been recognized as extremely effective catalysts. Among catalysts, gold is now valued because it doesn't tarnish or oxidize, a process that can shorten a catalyst's lifespan. Palladium is typically prized because it is especially good at binding and inducing molecules to reduce or oxidize. Wong and colleagues have demonstrated a way to bring these two metals together with better control. They build their catalysts on gold spheres that are about four nanometers in diameter. The spheres are partially covered with palladium, so that the particles' surface contains some gold and some palladium.

Wong and colleagues have shown that covering 60-80 percent of the gold's surface area with palladium typically produces the ideal catalyst -- though the exact percentage varies for different reactions.

"Our synthesis knob, the thing we use to dial in the efficiency, is the coverage area, and the precision of that knob is really what sets us apart from other people who are studying bimetallic catalysis," Wong said. "That precision is what produces these beautiful volcano plots, but it also helps in another way because it allows us to develop a rigorous explanation for the effects that we're measuring."

In the latest study, Wong, Rice graduate student and lead author Zhun Zhao and colleagues from Rice, Argonne National Laboratory and the University of Groningen in Holland used high-powered X-ray spectroscopy and other techniques to show that the "Goldilocks" coverage area for glycerol catalysis was about 60 percent.

"Palladium by itself oxidizes, which is not good because it slows down the catalysis," Zhao said. "We found that the gold in our catalysts helps stabilize the palladium and prevents it from degrading. The catalysts in our tests had extremely high durability. Our best catalyst produced a glycerol product with higher purity and in less time than anything else we found in the literature."

Wong said the research opens up an exciting new area of exploration for his lab.

"Now that we understand how these work with glycerol, we can study reactions of other biomass molecules like glucose, a building block of plants," Wong said.

###

Additional co-authors include Rice's Lori Pretzer, Pongsak Limpornpipat, James Clomburg and Ramon Gonzalez, Groningen's Joni Arentz and Argonne's Neil Schweitzer, Tianpin Wu and Jeffrey Miller. The research was supported by the National Science Foundation, the Welch Foundation, the Sigma Xi Grants-in-Aid of Research program, Rice University and the Department of Energy.

A copy of the Chemical Science paper is available at:

http://pubs.rsc.org/en/content/articlepdf/2014/sc/c4sc01001a

This release can be found online at news.rice.edu.

Follow Rice News and Media Relations on Twitter @RiceUNews.

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,920 undergraduates and 2,567 graduate students, Rice's undergraduate student-to-faculty ratio is 6.3-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 2 for "best value" among private universities by Kiplinger's Personal Finance.

David Ruth | Eurek Alert!

Further reports about: Palladium biomass catalysts chemicals glycerol volcano

More articles from Life Sciences:

nachricht New Model of T Cell Activation
27.05.2016 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht Fungi – a promising source of chemical diversity
27.05.2016 | Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie - Hans-Knöll-Institut (HKI)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Worldwide Success of Tyrolean Wastewater Treatment Technology

A biological and energy-efficient process, developed and patented by the University of Innsbruck, converts nitrogen compounds in wastewater treatment facilities into harmless atmospheric nitrogen gas. This innovative technology is now being refined and marketed jointly with the United States’ DC Water and Sewer Authority (DC Water). The largest DEMON®-system in a wastewater treatment plant is currently being built in Washington, DC.

The DEMON®-system was developed and patented by the University of Innsbruck 11 years ago. Today this successful technology has been implemented in about 70...

Im Focus: Computational high-throughput screening finds hard magnets containing less rare earth elements

Permanent magnets are very important for technologies of the future like electromobility and renewable energy, and rare earth elements (REE) are necessary for their manufacture. The Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, has now succeeded in identifying promising approaches and materials for new permanent magnets through use of an in-house simulation process based on high-throughput screening (HTS). The team was able to improve magnetic properties this way and at the same time replaced REE with elements that are less expensive and readily available. The results were published in the online technical journal “Scientific Reports”.

The starting point for IWM researchers Wolfgang Körner, Georg Krugel, and Christian Elsässer was a neodymium-iron-nitrogen compound based on a type of...

Im Focus: Atomic precision: technologies for the next-but-one generation of microchips

In the Beyond EUV project, the Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena are developing key technologies for the manufacture of a new generation of microchips using EUV radiation at a wavelength of 6.7 nm. The resulting structures are barely thicker than single atoms, and they make it possible to produce extremely integrated circuits for such items as wearables or mind-controlled prosthetic limbs.

In 1965 Gordon Moore formulated the law that came to be named after him, which states that the complexity of integrated circuits doubles every one to two...

Im Focus: Researchers demonstrate size quantization of Dirac fermions in graphene

Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices

Quantum mechanics is the field of physics governing the behavior of things on atomic scales, where things work very differently from our everyday world.

Im Focus: Graphene: A quantum of current

When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene

In 2010 the Nobel Prize in physics was awarded for the discovery of the exceptional material graphene, which consists of a single layer of carbon atoms...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking 4.0: International Laser Technology Congress AKL’16 Shows New Ways of Cooperations

24.05.2016 | Event News

Challenges of rural labor markets

20.05.2016 | Event News

International expert meeting “Health Business Connect” in France

19.05.2016 | Event News

 
Latest News

11 million Euros for research into magnetic field sensors for medical diagnostics

27.05.2016 | Awards Funding

Fungi – a promising source of chemical diversity

27.05.2016 | Life Sciences

New Model of T Cell Activation

27.05.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>