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 What happens in the cell nucleus after fertilization
06.12.2016 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Simple processing technique could cut cost of organic PV and wearable electronics

06.12.2016 | Materials Sciences

3-D printed kidney phantoms aid nuclear medicine dosing calibration

06.12.2016 | Medical Engineering

Robot on demand: Mobile machining of aircraft components with high precision

06.12.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>