Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > How Size Matters for Catalysts

University of Utah chemistry Prof. Scott Anderson and doctoral student Bill Kaden work on the elaborate apparatus they use to produce and study catalysts, which are substances that speed chemical reactions without being consumed. The world economy depends on catalysts, and the Utah research is aimed at making cheaper, more efficient catalysts, which could improve energy production and reduce emissions of Earth-warming gases.

Photo Credit: William Kunkel
University of Utah chemistry Prof. Scott Anderson and doctoral student Bill Kaden work on the elaborate apparatus they use to produce and study catalysts, which are substances that speed chemical reactions without being consumed. The world economy depends on catalysts, and the Utah research is aimed at making cheaper, more efficient catalysts, which could improve energy production and reduce emissions of Earth-warming gases. Photo Credit: William Kunkel

Abstract:
Study Links Size, Activity, Electronic Properties

How Size Matters for Catalysts

Salt Lake City, UT | Posted on November 8th, 2009

University of Utah chemists demonstrated the first conclusive link between the size of catalyst particles on a solid surface, their electronic properties and their ability to speed chemical reactions. The study is a step toward the goal of designing cheaper, more efficient catalysts to increase energy production, reduce Earth-warming gases and manufacture a wide variety of goods from medicines to gasoline.

Catalysts are substances that speed chemical reactions without being consumed by the reaction. They are used to manufacture most chemicals and many industrial products. The world's economy depends on them.

"One of the big uncertainties in catalysis is that no one really understands what size particles of the catalyst actually make a chemical reaction happen," says Scott Anderson, a University of Utah chemistry professor and senior author of the study in the Friday, Nov. 6 issue of the journal Science. "If we could understand what factors control activity in catalysts, then we could make better and less expensive catalysts."

"Most catalysts are expensive noble metals like gold or palladium or platinum," he adds. "Say in a gold catalyst, most of the metal is in the form of large particles, but those large particles are inactive and only nanoparticles with about 10 atoms are active. That means more than 90 percent of gold in the catalyst isn't doing anything. If you could make a catalyst with only the right size particles, you could save 90 percent of the cost or more."

In addition, "there's a huge amount of interest in learning how to make catalysts out of much less expensive base metals like copper, nickel and zinc," Anderson says. "And the way you are going to do that is by 'tuning' their chemical properties, which means tuning the electronic properties because the electrons control the chemistry."

The idea is to "take a metal that is not catalytically active and, when you reduce it to the appropriate size [particles], it can become catalytic," Anderson says. "That's the focus of our work - to try to identify and understand what sizes of metal particles are active as catalysts and why they are active as catalysts."

In the new study, Anderson and his students took a step toward "tuning" catalysts to have desired properties by demonstrating, for the first time, that the size of metal catalyst "nanoparticles" deposited on a surface affects not only the catalyst's level of activity, but the particles' electronic properties.

Anderson conducted the study with chemistry doctoral students Bill Kaden and William Kunkel, and with former doctoral student Tianpin Wu. Kaden was first author.

The Economy Depends on Catalysts

"Catalysts are a huge part of the economy," Anderson says. "Catalysts are used for practically every industrial process, from making gasoline and polymers to pollution remediation and rocket thrusters."

Catalysts are used in 90 percent of U.S. chemical manufacturing processes and to make more than 20 percent of all industrial products, and those processes consume large amounts of energy, according to the U.S. Department of Energy (DOE).

In addition, industry produces 21 percent of U.S. Earth-warming carbon dioxide emissions - including 3 percent by the chemical industry, DOE says.

Thus, improving the efficiency of catalysts is "the key to both energy savings and carbon dioxide emissions reductions," the agency says.

Catalysts also are used in drug manufacturing; food processing; fuel cells; fertilizer production; conversion of natural gas, coal or biomass into liquid fuels; and systems to reduce pollutants and improve the efficiency of combustion in energy production.

The North American Catalysis Society says catalysts contribute 35 percent or more of global Gross Domestic Product. "The biggest part of this contribution comes from generation of high energy fuels (gasoline, diesel, hydrogen), which depend critically on the use of small amounts of catalysts in … petroleum refineries," the group says.

"The development of inexpensive catalysts … is pivotal to energy capture, conversion and storage," says Henry White, professor and chair of chemistry at the University of Utah. "This research is vital to the energy security of the nation."

Catalyst Research: What Previous Studies and the New Study Showed

Many important catalysts - such as those in catalytic converters that reduce motor vehicle emissions - are made of metal particles that range in size from microns (millionths of a meter) down to nanometers (billionths of a meter).

As the size of a catalyst metal particle is reduced into the nanoscale, its properties initially remain the same as a larger particle, Anderson says. But when the size is smaller than about 10 nanometers - containing about 10,000 atoms of catalyst - the movements of electrons in the metal are confined, so their inherent energies are increased.

When there are fewer than about 100 atoms in catalyst particles, the size variations also result in fluctuations in the electronic structure of the catalyst atoms. Those fluctuations strongly affect the particles' ability to act as a catalyst, Anderson says.

Previous experiments documented that electronic and chemical properties of a catalyst are affected by the size of catalyst particles floating in a gas. But those isolated catalyst particles are quite different than catalysts that are mounted on a metal oxide surface - the way the catalyst metal is supported in real industrial catalysts.

Past experiments with catalysts mounted on a surface often included a wide variety of particle sizes. So those experiments failed to detect how the catalyst's chemical activity and electronic properties vary depending with the size of individual particles.

Anderson was the first American chemist to sort metal catalyst particles by size and demonstrate how their reactivity changes with size. In previous work, he studied gold catalyst particles deposited on titanium dioxide.

The new study used palladium particles of specific sizes that were deposited on titanium dioxide and used to convert carbon monoxide into carbon dioxide.

The study not only showed how catalytic activity varies with catalyst particle size, "but we have been able to correlate that size dependence with observed electronic differences in the catalyst particles," Kaden says. "People had speculated this should be happening, but no one has ever seen it."

Anderson says it is the first demonstration of a strong correlation between the size and activity of a catalyst on a metal surface and electronic properties of the catalyst.

How the Study was Conducted

Using an elaborate apparatus in Anderson's laboratory, the chemists aimed a laser beam to vaporize palladium, creating electrically charged, palladium nanoparticles in a vapor carried by a stream of helium gas.

Electromagnetic fields are used to capture the particles and send them through a mass spectrometer, which selects only the sizes of palladium particles Anderson and colleagues want to study. The desired particles then are deposited on a single crystal of titanium oxide that measures less than a half-inch on a side.

Next, the chemists use various methods to characterize the sample of palladium catalyst particles: specifically the palladium catalyst's electronic properties, physical shape and chemical activity.

####

Contacts:
Scott Anderson
professor of chemistry
Office phone: (801) 585-7289
Cell phone: (801) 413-9174


Bill Kaden
doctoral student in chemistry
Office phone: (801) 581-6644


Lee J. Siegel
science news specialist, University of Utah Public Relations
Office phone: (801) 581-8993
Cell phone: (801) 244-5399

Copyright © University of Utah

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Evidence mounts for quantum criticality theory: Findings bolster theory that quantum fluctuations drive strange electronic phenomena January 30th, 2015

Everything You Need To Know About Nanopesticides January 30th, 2015

DNA nanoswitches reveal how life's molecules connect: An accessible new way to study molecular interactions could lower cost and time associated with discovering new drugs January 30th, 2015

Crystal light: New light-converting materials point to cheaper, more efficient solar power: University of Toronto engineers study first single crystal perovskites for new solar cell and LED applications January 30th, 2015

Park Systems Announces Innovations in Bio Cell Analysis with the Launch of Park NX-Bio, the only 3-in-1 Imaging Nanoscale Tool Available for Life Science Researchers January 29th, 2015

Chemistry

Creating new materials with quantum effects for electronics January 29th, 2015

Anti-microbial coatings with a long-term effect for surfaces – presentation at nano tech 2015 in Japan January 21st, 2015

Hydrogels deliver on blood-vessel growth: Rice researchers introduce improved injectable scaffold to promote healing January 20th, 2015

Possible Futures

GS7 Graphene Sensor maybe Solution in Fight Against Cancer January 25th, 2015

Nanotechnology in Energy Applications Market Research Report 2014-2018: Radiant Insights, Inc January 15th, 2015

'Mind the gap' between atomically thin materials December 23rd, 2014

A novel method for identifying the body’s ‘noisiest’ networks November 19th, 2014

Announcements

Evidence mounts for quantum criticality theory: Findings bolster theory that quantum fluctuations drive strange electronic phenomena January 30th, 2015

Everything You Need To Know About Nanopesticides January 30th, 2015

DNA nanoswitches reveal how life's molecules connect: An accessible new way to study molecular interactions could lower cost and time associated with discovering new drugs January 30th, 2015

Crystal light: New light-converting materials point to cheaper, more efficient solar power: University of Toronto engineers study first single crystal perovskites for new solar cell and LED applications January 30th, 2015

Food/Agriculture/Supplements

Everything You Need To Know About Nanopesticides January 30th, 2015

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

Nanosensor Used for Simultaneous Determination of Effective Tea Components January 24th, 2015

Transparent artificial nacre: A brick wall at the nanoscale January 22nd, 2015

Environment

Iranian Scientists Use MOFs to Eliminate Dye Pollutants January 29th, 2015

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

Magnetic Nanosorbents Able to Eliminate Chemical Contaminants January 19th, 2015

Malaysian Nanotechnology Company Nanopac Innovation Ltd. lists on the NSX January 19th, 2015

Energy

Crystal light: New light-converting materials point to cheaper, more efficient solar power: University of Toronto engineers study first single crystal perovskites for new solar cell and LED applications January 30th, 2015

Los Alamos Develops New Technique for Growing High-Efficiency Perovskite Solar Cells: Researchers’ crystal-production insights resolve manufacturing difficulty January 29th, 2015

Carbon nanoballs can greatly contribute to sustainable energy supply January 27th, 2015

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Automotive/Transportation

Teijin to Participate in Nano Tech 2015 January 22nd, 2015

Materials - Efficient catalysts... January 13th, 2015

Waterloo chemist one step closer to a new generation of electric car battery January 12th, 2015

New concept of fuel cell for efficiency and environment: It grasps both performance efficiency and removal of toxic heavy metal ions in direct methanol fuel cells January 5th, 2015

Aerospace/Space

Asteroid Mining 101: A New Book by World-Renowned Expert Dr. John S. Lewis - Exclusive Sneak-Peek Opportunity for Book Reviewers and Media January 29th, 2015

Scientists 'bend' elastic waves with new metamaterials that could have commercial applications: Materials could benefit imaging and military enhancements such as elastic cloaking January 23rd, 2015

Teijin to Participate in Nano Tech 2015 January 22nd, 2015

Production of Special Nanocomposite in Iran with Application in Railways December 23rd, 2014

Industrial

Industrial Nanotech, Inc. Announces New OEM Customer January 27th, 2015

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

Iranian Scientists Produce Graphene-Based Oxygen Sensor January 23rd, 2015

Teijin to Participate in Nano Tech 2015 January 22nd, 2015

Fuel Cells

New concept of fuel cell for efficiency and environment: It grasps both performance efficiency and removal of toxic heavy metal ions in direct methanol fuel cells January 5th, 2015

Toward a low-cost 'artificial leaf' that produces clean hydrogen fuel December 3rd, 2014

Single-atom gold catalysts may offer path to low-cost production of fuel and chemicals November 28th, 2014

National Synchrotron Light Source II Achieves 'First Light' October 23rd, 2014

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE