Doe Science news source
The DOE Science News Source is a Newswise initiative to promote research news from the Office of Science of the DOE to the public and news media.
  • 2017-05-02 11:05:04
  • Article ID: 673966

Fight to the Top: Silver and Gold Compete for the Surface of a Bimetallic Solid

Keeping mobile metals fixed for commodity chemical production

  • Credit: Image: Nathan Johnson, Pacific Northwest National Lab

    Silver atoms migrate in an alloy, changing the material’s structure and reactivity as they do so. Understanding the changes is key to creating more energy-efficient catalysts

  • Credit: Image: Nicholas Gould, CCEI EFRC

    An alloy surface forms reactive oxygen. (Au): Gold, (Ag): Silver, (O): Oxygen.

  • Credit: Image: Nicholas Gould, CCEI EFRC

    (A) Low-magnification image of the alloy during ozone treatment. (B) Increased magnification image of an oxygen-rich layer formed during ozone treatment.

  • Credit: Image: Nicholas Gould, CCEI EFRC

    (A) Low-magnification image of the alloy shortly after methanol treatment. (B) Increased magnification image of the removal of the oxygen-rich surface in the previous figure (right), and the formation of gold-rich particles (red square).

It’s the classic plot of a buddy movie. Two struggling bodies team up to drive the plot and do good together. That same idea, when it comes to metals, could help scientists solve a big problem: the amount of energy consumed by making chemicals.

Before delving into the intricacies of the chemistry in question, an introduction to alloys and their uses is beneficial. An alloy is a mixture of metals that often has properties superior to the sum of its parts. For example, stainless steel is an alloy of mostly iron and chromium, and the mixture has the strength of iron and the corrosion resistance of chromium, yielding a symbiotic solid solution. Alloys are commonly used as catalysts to accelerate a chemical reaction to form valuable products.

The transformation of methanol (CH3OH) to methyl formate (C2H4O2) is important for industrial production of chemicals critical to modern life, such as formamides and formic acid, which are precursors to pharmaceuticals and agricultural herbicides and pesticides. These chemicals are produced on such a large scale that improvement in reaction efficiency would result in significant energy savings and reduced environmental impact.

However, the reaction is tricky. Oxygen in the air we breathe cannot react with methanol to create formate, because it exists as a pair of oxygen atoms. But most metal surfaces can break oxygen-oxygen bonds to form oxygen atoms that are reactive, the exception being pure gold. Yet a gold-silver alloy has unusual properties, including creation of gold-oxygen bonds that pure gold cannot form. This is a similar phenomenon to formation of rust on iron surfaces, where rust is simply iron-oxygen bonds.

Recently, researchers at the Integrated Mesoscale Architectures for Sustainable Catalysis, an Energy Frontier Research Center, investigated a gold-and-silver alloy for turning methanol into methyl formate. The material is highly porous, which gives it a high contact area with any gases flowing through it. However, the material has surprisingly dynamic properties, and as the alloy is exposed to different gas streams, the positions of gold and silver atoms rearrange. Some arrangements led to the desired methyl formate, while others led to valueless carbon dioxide. The challenge is to understand how the alloy restructures during the reaction, and how to maintain the desired configuration. Initially, the catalyst had to be treated with gaseous flowing ozone, O3 (three oxygens bonded together), to form the desired structure.

The team examined the alloy using high-resolution microscopy at Brookhaven National Laboratory and X-ray photoelectron spectroscopy at Lawrence Berkeley National Laboratory. By looking closely and probing only the first few layers of the material, the team identified the structure responsible for methyl formate production. They discovered that silver-and-gold alloys, enriched in silver (greater than the overall 3 percent), catalyze methanol conversion to methyl formate. During ozone treatment, the silver atoms are enriched on the surface. In other words, silver atoms inside the metal alloy reacted with ozone and migrated towards the surface to form silver-oxygen and gold-oxygen bonds.

When the feed is switched from ozone to methanol, the methanol reacts with the surface oxygen. Initially, the methanol reacts to carbon dioxide, but after the surface oxygen is depleted, the methanol converts to valuable methyl formate. Surprisingly, as the oxygen is consumed, silver migrates into the subsurface — a few layers of atoms below the surface — forming a local surface alloy. This structural change coincided with the formation of a new oxygen species and the production of methyl formate. Thus, at this point, the alloy was in an optimal structure to create methyl formate.

However, further exposure to methanol removed the oxygen responsible for methyl formate production and caused further, detrimental rearrangements of the silver and gold atoms. Fortunately, the team found that supplementing the methanol feed with oxygen allowed for the continual regeneration of the valuable oxygen species responsible for formate production. Thus, a key factor for maintaining the methyl formate production is to keep the subsurface silver alloy structure from rearranging. The team prevented the alloy from restructuring by using the right operating temperature and oxygen content in the methanol stream.

The novelty of this work lies in its observations of the catalyst behavior during the reaction. The work demonstrates the dynamic nature of the catalyst and shows that the products are sensitive to the catalyst structure. The knowledge of how catalysts restructure during the reaction will lead to using the proper conditions and, ultimately, lower costs and environmental impact for commodity chemical production.

Acknowledgments: 

This work was supported as part of the Integrated Mesoscale Architectures for Sustainable Catalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Work at Lawrence Livermore National Laboratory was performed under the auspices of the U.S. Department of Energy. This research used resources of the Center for Functional Nanomaterials, a U.S. Department of Energy Office of Science user facility. It also used resources of the Advanced Light Source, a U.S. Department of Energy Office of Science user facility.

More Information: 

Zugic B, L Wang, C Heine, DN Zakharov, BAJ Lechner, EA Stach, J Biener, M Salmeron, RJ Madix, and CM Friend. 2016. “Dynamic Restructuring Drives Catalytic Activity on Nanoporous Gold-Silver Alloy Catalysts.” Nature Materials 1(December):1-8. DOI: 10.1038/nmat4824

This item, written by Nicholas Gould, is part of Frontiers in Energy Research, a newsletter for the Energy Frontier Research Centers created by early career members of the centers. See http://www.energyfrontier.us/newsletter/

X
X
X
  • Filters

  • × Clear Filters

Nanoparticle Supersoap Creates 'Bijel' With Potential as Sculptable Fluid

A new type of "bijel" created by Berkeley Lab scientists could one day lead to applications in soft robotics, liquid circuitry, and energy conversion.

With Extra Sugar, Leaves Get Fat Too

Eat too much without exercising and you'll probably put on a few pounds. As it turns out, plant leaves do something similar. In a new study at the U.S. Department of Energy's Brookhaven National Laboratory, scientists show that retaining sugars in plant leaves can make them get fat too. In plants, this extra fat accumulation could be a good thing.

High-Speed Movie Aids Scientists Who Design Glowing Molecules

In a recent experiment conducted at the Department of Energy's SLAC National Accelerator Laboratory, a research team used bright, ultrafast X-ray pulses from SLAC's X-ray free-electron laser to create a high-speed movie of a fluorescent protein in action. With that information, the scientists began to design a marker that switches more easily, a quality that can improve resolution during biological imaging.

Biomass-Produced Electricity in the US Possible, but It'll Cost

If the U.S. wants to start using wood pellets to produce energy, either the government or power customers will have to pay an extra cost, a new University of Georgia study has found.

Scientists Make Atoms-Thick Post-It Notes for Solar Cells and Circuits

In a study published Sept. 20 in Nature, UChicago and Cornell University researchers describe an innovative method to make stacks of semiconductors just a few atoms thick. The technique offers scientists and engineers a simple, cost-effective method to make thin, uniform layers of these materials, which could expand capabilities for devices from solar cells to cell phones.

Titan Helps Researchers Suck Mystery Out of Cell's 'Vacuum Cleaners'

In cancer cells, a membrane transport protein called P-glycoprotein, or Pgp, actively pumps anticancer drugs out of the cell, contributing to multidrug resistance. Recently, a team led by computational biophysicist Emad Tajkhorshid from the University of Illinois at Urbana-Champaign (UIUC) used the Titan supercomputer to uncover new details about Pgp that could help the drug discovery community manipulate Pgp function.

Laser-Free Method of Ion Cooling Has Range of Potential Uses

Prof. Daniel Zajfman's universal ion trap cools to a tenth of a degree above absolute zero. The new method does not depend on the type or the weight of the ion and, thus, might be used to investigate the properties of large biological molecules or nanoparticles, among other things.

Tiny Lasers from a Gallery of Whispers

Whispering gallery mode resonators rely on a phenomenon similar to an effect observed in circular galleries, and the same phenomenon applies to light. When light is stored in ring-shaped or spherical active resonators, the waves superimpose in such a way that it can result in laser light. This week in APL Photonics, investigators report a new type of dye-doped WGM micro-laser that produces light with tunable wavelengths.

Copper Catalyst Yields High Efficiency CO2-to-Fuels Conversion

Berkeley Lab scientists have developed a new electrocatalyst that can directly convert carbon dioxide into multicarbon fuels and alcohols using record-low inputs of energy. The work is the latest in a round of studies coming out of Berkeley Lab tackling the challenge of a creating a clean chemical manufacturing system that can put carbon dioxide to good use.

Solar-to-Fuel System Recycles CO2 to Make Ethanol and Ethylene

Berkeley Lab scientists have harnessed the power of photosynthesis to convert carbon dioxide into fuels and alcohols at efficiencies far greater than plants. The achievement marks a significant advance in the effort to move toward sustainable sources of fuel.


  • Filters

  • × Clear Filters

PPPL Physicist Francesca Poli Named ITER Scientist Fellow

Article describes new ITER Scientist Fellow.

Los Alamos Gains Role in High-Performance Computing for Materials Program

A new high-performance computing initiative announced this week by the U.S. Department of Energy will help U.S. industry accelerate the development of new or improved materials for use in severe environments.

UK Commits $88 Million to LBNF/DUNE in First-Ever Umbrella Science Agreement with U.S.

The UK has committed $88 million to the Long-Baseline Neutrino Facility and Deep Underground Neutrino Experiment as part of an umbrella science and technology agreement with the United States.

Wayne State Receives $1.2 Million NSF Grant to Develop Autonomous Battery Operating System

Researchers at Wayne State University led by Nathan Fisher, associate professor of computer science in the College of Engineering, received a $1.2 million grant from the National Science Foundation to address the need for effective, integrative battery operating systems that provide sustained and reliable power.

UAH leads effort that secures $20 million grant from the National Science Foundation

A partnership comprising nine universities in Alabama, including The University of Alabama in Huntsville (UAH) as the lead institution, has been awarded a $20 million, five-year grant by the National Science Foundation's Experimental Program to Stimulate Competitive Research (EPSCoR).

Sandia Labs Wins 5 Regional Technology Transfer Awards

Sandia National Laboratories won five awards from the 2017 Federal Laboratory Consortium for its work to develop and commercialize innovative technologies.

Tulane Receives Grant to Reduce Auto Emissions

Members of Tulane University's Shantz Lab will work with industrial scientists to assist in the development of next-generation materials designed to reduce harmful automotive emissions. The three-year old lab and its group of students have received a grant and equipment resources from SACHEM, Inc., a chemical science company.

Lab Leads New Effort in Materials Development

Lawrence Livermore National Lab will be part of a multi-lab effort to apply high-performance computing to US-based industry's discovery, design, and development of materials for severe environments under a new initiative announced by the Department of Energy (DOE) on Sept. 19.

ORNL Innovation Crossroads Program Opens Second Round of Energy Entrepreneurial Fellowships

Entrepreneurs are invited to apply for the second round of Oak Ridge National Laboratory's Innovation Crossroads program.

Los Alamos Recognized as Top Diversity Employer

For the second straight year, Los Alamos National Laboratory was recognized as a top diversity employer by LATINA Style and STEM Workforce Diversity magazine.


  • Filters

  • × Clear Filters

Fungi: Gene Activator Role Discovered

Specific modifications to fungi DNA may hold the secret to turning common plant degradation agents into biofuel producers.

First Look at a Living Cell Membrane

Neutrons provide the solution to nanoscale examination of living cell membrane and confirm the existence of lipid rafts.

High Yield Biomass Conversion Strategy Ready for Commercialization

Researchers convert 80 percent of biomass into high-value products with strategy that's ready for commercialization.

Consequences of Drought Stress on Biofuels

Switchgrass cultivated during a year of severe drought inhibited microbial fermentation and resulting biofuel production.

Clay Minerals and Metal Oxides Change How Uranium Travels Through Sediments

Montmorillonite clays prevent uranium from precipitating from liquids, letting it travel with groundwater.

Tundra Loses Carbon with Rapid Permafrost Thaw

Seven-year-study shows plant growth does not sustainably balance carbon losses from solar warming and permafrost thaw.

Crystals Grow by Twisting, Aligning and Snapping Together

Van der Waals force, which that enables tiny crystals to grow, could be used to design new materials.

Vitamin B12 Fuels Microbial Growth

Scarce compound, vitamin B12, is key for cellular metabolism and may help shape microbial communities that affect environmental cycles and bioenergy production.

Carbon in Floodplain Unlikely to Cycle into the Atmosphere

Microbes leave a large fraction of carbon in anoxic sediments untouched, a key finding for understanding how watersheds influence Earth's ecosystem.

Bacterial Cell Wall Changes Produce More Fatty Molecules

New strategy greatly increases the production and secretion of biofuel building block lipids in bacteria able to grow at industrial scales.


Spotlight

Thursday September 21, 2017, 03:05 PM

From Science to Finance: SLAC Summer Interns Forge New Paths in STEM

SLAC National Accelerator Laboratory

Thursday September 07, 2017, 02:05 PM

Students Discuss 'Cosmic Opportunities' at 45th Annual SLAC Summer Institute

SLAC National Accelerator Laboratory

Thursday August 31, 2017, 05:05 PM

Binghamton University Opens $70 Million Smart Energy Building

Binghamton University, State University of New York

Wednesday August 23, 2017, 05:05 PM

Widening Horizons for High Schoolers with Code

Argonne National Laboratory

Saturday May 20, 2017, 12:05 PM

Rensselaer Polytechnic Institute Graduates Urged to Embrace Change at 211th Commencement

Rensselaer Polytechnic Institute (RPI)

Monday May 15, 2017, 01:05 PM

ORNL, University of Tennessee Launch New Doctoral Program in Data Science

Oak Ridge National Laboratory

Friday April 07, 2017, 11:05 AM

Champions in Science: Profile of Jonathan Kirzner

Department of Energy, Office of Science

Wednesday April 05, 2017, 12:05 PM

High-Schooler Solves College-Level Security Puzzle From Argonne, Sparks Interest in Career

Argonne National Laboratory

Tuesday March 28, 2017, 12:05 PM

Champions in Science: Profile of Jenica Jacobi

Department of Energy, Office of Science

Friday March 24, 2017, 10:40 AM

Great Neck South High School Wins Regional Science Bowl at Brookhaven Lab

Brookhaven National Laboratory

Wednesday February 15, 2017, 04:05 PM

Middle Schoolers Test Their Knowledge at Science Bowl Competition

Argonne National Laboratory

Friday January 27, 2017, 04:00 PM

Haslam Visits ORNL to Highlight State's Role in Discovering Tennessine

Oak Ridge National Laboratory

Tuesday November 08, 2016, 12:05 PM

Internship Program Helps Foster Development of Future Nuclear Scientists

Oak Ridge National Laboratory

Friday May 13, 2016, 04:05 PM

More Than 12,000 Explore Jefferson Lab During April 30 Open House

Thomas Jefferson National Accelerator Facility

Monday April 25, 2016, 05:05 PM

Giving Back to National Science Bowl

Ames Laboratory

Friday March 25, 2016, 12:05 PM

NMSU Undergrad Tackles 3D Particle Scattering Animations After Receiving JSA Research Assistantship

Thomas Jefferson National Accelerator Facility

Tuesday February 02, 2016, 10:05 AM

Shannon Greco: A Self-Described "STEM Education Zealot"

Princeton Plasma Physics Laboratory

Monday November 16, 2015, 04:05 PM

Rare Earths for Life: An 85th Birthday Visit with Mr. Rare Earth

Ames Laboratory

Tuesday October 20, 2015, 01:05 PM

Meet Robert Palomino: 'Give Everything a Shot!'

Brookhaven National Laboratory

Tuesday April 22, 2014, 11:30 AM

University of Utah Makes Solar Accessible

University of Utah

Wednesday March 06, 2013, 03:40 PM

Student Innovator at Rensselaer Polytechnic Institute Seeks Brighter, Smarter, and More Efficient LEDs

Rensselaer Polytechnic Institute (RPI)

Friday November 16, 2012, 10:00 AM

Texas Tech Energy Commerce Students, Community Light up Tent City

Texas Tech University

Wednesday November 23, 2011, 10:45 AM

Don't Get 'Frosted' Over Heating Your Home This Winter

Temple University

Wednesday July 06, 2011, 06:00 PM

New Research Center To Tackle Critical Challenges Related to Aircraft Design, Wind Energy, Smart Buildings

Rensselaer Polytechnic Institute (RPI)

Friday April 22, 2011, 09:00 AM

First Polymer Solar-Thermal Device Heats Home, Saves Money

Wake Forest University

Friday April 15, 2011, 12:25 PM

Like Superman, American University Will Get Its Energy from the Sun

American University

Thursday February 10, 2011, 05:00 PM

ARRA Grant to Help Fund Seminary Building Green Roof

University of Chicago

Tuesday December 07, 2010, 05:00 PM

UC San Diego Installing 2.8 Megawatt Fuel Cell to Anchor Energy Innovation Park

University of California San Diego

Monday November 01, 2010, 12:50 PM

Rensselaer Smart Lighting Engineering Research Center Announces First Deployment of New Technology on Campus

Rensselaer Polytechnic Institute (RPI)

Friday September 10, 2010, 12:40 PM

Ithaca College Will Host Regional Clean Energy Summit

Ithaca College

Tuesday July 27, 2010, 10:30 AM

Texas Governor Announces $8.4 Million Award to Create Renewable Energy Institute

Texas Tech University

Friday May 07, 2010, 04:20 PM

Creighton University to Offer New Alternative Energy Program

Creighton University

Wednesday May 05, 2010, 09:30 AM

National Engineering Program Seeks Subject Matter Experts in Energy

JETS Junior Engineering Technical Society

Wednesday April 21, 2010, 12:30 PM

Students Using Solar Power To Create Sustainable Solutions for Haiti, Peru

Rensselaer Polytechnic Institute (RPI)

Wednesday March 03, 2010, 07:00 PM

Helping Hydrogen: Student Inventor Tackles Challenge of Hydrogen Storage

Rensselaer Polytechnic Institute (RPI)

Thursday February 04, 2010, 02:00 PM

Turning Exercise into Electricity

Furman University

Thursday November 12, 2009, 12:45 PM

Campus Leaders Showing the Way to a Sustainable, Clean Energy Future

National Wildlife Federation (NWF)

Tuesday November 03, 2009, 04:20 PM

Furman University Receives $2.5 Million DOE Grant for Geothermal Project

Furman University

Thursday September 17, 2009, 02:45 PM

Could Sorghum Become a Significant Alternative Fuel Source?

Salisbury University

Wednesday September 16, 2009, 11:15 AM

Students Navigating the Hudson River With Hydrogen Fuel Cells

Rensselaer Polytechnic Institute (RPI)

Wednesday September 16, 2009, 10:00 AM

College Presidents Flock to D.C., Urge Senate to Pass Clean Energy Bill

National Wildlife Federation (NWF)

Wednesday July 01, 2009, 04:15 PM

Northeastern Announces New Professional Master's in Energy Systems

Northeastern University

Friday October 12, 2007, 09:35 AM

Kansas Rural Schools To Receive Wind Turbines

Kansas State University

Thursday August 17, 2006, 05:30 PM

High Gas Prices Here to Stay, Says Engineering Professor

Rowan University

Wednesday May 17, 2006, 06:45 PM

Time Use Expert's 7-Year Fight for Better Gas Mileage

University of Maryland, College Park





Showing results

0-4 Of 2215