Subscribe free to our newsletters via your
. 24/7 Space News .


Subscribe free to our newsletters via your




















TECH SPACE
New catalyst makes hydrogen peroxide accessible to developing world
by Staff Writers
Bethlehem PA (SPX) Mar 02, 2016


In an article published in Science a group of researchers from the United Kingdom and the United States has reported that bimetallic compounds consisting of palladium and any one of six other elements can effectively catalyse the hydrogenation of oxygen to form hydrogen peroxide.

Hydrogen peroxide is one of the most common and versatile of household products. In dilute form, it can disinfect wounds and bleach hair, whiten teeth and remove stains from clothing, clean contact lenses and kill mold and algae.

In high concentrations, hydrogen peroxide (H2O2) can be catalytically decomposed into oxygen and steam and used as a propellant or as an explosive itself.

Hydrogen peroxide is typically made in a multi-step, energy-intensive process that requires it to be produced in large quantities and shipped and stored in a highly concentrated form.

Now a group of researchers from the United Kingdom and the United States has developed a method of producing hydrogen peroxide on demand through a simple, one-step process. The method enables dilute H2O2 to be made directly from hydrogen and oxygen in small quantities on-site, making it more accessible to underdeveloped regions of the world, where it could be used to purify water.

In an article published in Science the group reported that bimetallic compounds consisting of palladium and any one of six other elements can effectively catalyse the hydrogenation of oxygen to form hydrogen peroxide. The project was led by Graham J. Hutchings, professor of physical chemistry and director of the Cardiff Catalysis Institute at Cardiff University in Wales.

The researchers say their new process overcomes a longstanding challenge to the catalytic production of hydrogen peroxide - namely the tendency of the catalyst to also quickly decompose the product into water soon after it has been made.

"Using our new catalyst, we've created a method of efficiently producing H2O2 on demand in a quick, one-step process," said Simon J. Freakley of the Cardiff Catalysis Institute, the article's lead author.

"Being able to produce H2O2 directly opens up a whole host of possibilities, most notably in the field of water purification [in areas] where safe and clean drinking water is at a premium."

The Science article, titled "Palladium-tin catalysts for the direct synthesis of H2O2 with high selectivity," was coauthored by other researchers from the Cardiff Catalysis Institute and from Lehigh University in Bethlehem, Pa., and the U.S. Department of Energy's Oak Ridge National Laboratory in Tennessee.

The article is the fourth on the topic that researchers from Cardiff and Lehigh have published in Science over the past decade. The first three dealt with advances in creating and using an alloy catalyst of gold and palladium; one, published in 2009, discussed that catalyst's potential to produce hydrogen peroxide quickly and efficiently while preventing its decomposition.

The new catalysts, said Christopher J. Kiely, can be made by combining palladium with tin, cobalt, nickel, gallium, indium or zinc, all of which are cheaper than gold. Furthermore, the catalyst can be made without the need to pre-treat the catalyst support with nitric acid, which is a requirement of the gold-palladium alloys.

"Scientists have known for more than a century that palladium metal can catalyse the direct reaction of hydrogen and oxygen to make hydrogen peroxide," said Kiely, professor of materials science and chemical engineering and director of Lehigh's Electron Microscopy and Nanofabrication Facility. "Unfortunately, the palladium also rapidly hydrogenates or decomposes the hydrogen peroxide that is produced to form water.

"In 2009, we figured out that gold-palladium nanoparticles, supported on acid-washed activated carbon, could switch off the second undesired reaction. But gold is expensive. For the catalyst to be industrially competitive, the gold needs to be replaced with a cheaper metal."

The group searched for a different metal to replace the gold, said Kiely, and found that a catalyst composed of palladium and tin could carry out the reaction to form hydrogen peroxide just as effectively as the gold-palladium catalyst. Subsequent tests showed that another five metals, in combination with palladium, also performed very well.

The group then used a variety of electron microscopy techniques to understand why palladium alloys caused the hydrogen peroxide that was produced to decompose and how this second reaction could be prevented. The answer, they learned, had to do with variations in the sizes and composition of the metal alloy catalyst particles.

"When you make a catalyst," said Kiely, "you always tend to generate catalyst particles that span a range of different sizes. When we measured the composition of the gold-palladium particles, it turned out that the larger particles contained a lot of gold while the smaller particles had a lot of palladium. Only the medium-sized particles had the right composition.

"While the larger particles make the hydrogen peroxide, the tiny palladium-rich particles efficiently convert the hydrogen peroxide to water. We had to find a way to stop these smaller particles from doing their job."

The group deposited a palladium-tin mixture onto a titanium dioxide (TiO2) support and observed that some of the tin spread out to form a very thin tin oxide layer over the TiO2 while the remainder was consumed in making palladium-tin alloy particles. The researchers developed a simple three-step heat treatment process that induced the secondary tin-oxide support layer to encapsulate the ultra-small palladium-rich particles. This served to muzzle the nuisance particles and prevent them from catalysing the hydrogenation and decomposition of the hydrogen peroxide.

"The heat treatment induced the tin-oxide layer to crawl over and effectively bury the small palladium-rich particles and stop them from working," said Kiely.

"More importantly, the larger palladium-tin alloy particles, which efficiently generate the hydrogen peroxide, were unaffected. This phenomenon, which is called a strong-metal-support-interaction, is normally not desired. You don't usually want the metal particles to be covered with thin oxide layers because that deactivates the catalysts. However, in this case we have managed to use the phenomenon selectively to deactivate only the small detrimental particles, while leaving the larger beneficial alloy particles free to do their work."

The group spent five years developing the palladium-tin catalyst and optimizing the heat treatment regimen, Kiely said.

"It was a long, hard slog to develop the material," he said, "but the resulting final catalyst has excellent performance characteristics."

In the Science article, the researchers said that the palladium-tin catalysts supported on titanium dioxide were able to switch off the hydrogenation of H2O2 and give an overall selectivity to the desired product of more than 95 percent.

The researchers analysed the catalyst materials using Oak Ridge's UltraSTEM (Scanning Transmission Electron Microscope), which is equipped with Electron Energy Loss Spectroscopy (EELS), along with two aberration-corrected instruments at Lehigh - the JEOL JEM-2200FS STEM and the JEOL JEM-ARM200CF atomic-resolution transmission electron microscope. In addition to Hutchings, Freakley and Kiely, the coauthors of the Science article are Qian He, Jonathan Harrhy, Li Lu, David A. Crole, David J. Morgan, Edwin N. Ntainjua, Jennifer K. Edwards, Albert F. Carley and Albina Borisevich.

.


Related Links
Lehigh University
Space Technology News - Applications and Research






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
TECH SPACE
Crystal and magnetic structure of multiferroic hexagonal manganite
Chester, UK (SPX) Feb 25, 2016
Ever since Curie conjectured on "the symmetry in physical phenomena, symmetry of an electric field and a magnetic field", it has long been a dream for material scientists to search for this rather unusual class of material exhibiting the coexistence of magnetism and ferroelectricity in a single compound known as a multiferroic compound. Multiferroic materials are a class of crystalline mat ... read more


TECH SPACE
New Lunar Exhibit Features NASA's Lunar Reconnaissance Orbiter Imagery

NASA releases strange 'music' heard by 1969 astronauts

NASA chooses ASU to design and operate special satellite

Chinese scientists invent leak detection system for moon exploration

TECH SPACE
Jarosite in the Noctis Labyrinthus Region of Mars

Trace Gas Orbiter and Schiaparelli are joined

Footprints of a martian flood

Russia plans return to Mars, Moon despite money woes

TECH SPACE
Tools and Talent at Michoud to Complete SLS Core Stage Welding in 2016

Orion Simulations Help Engineers Evaluate Mission Operations for Crew

Orion Test Hardware in Position for Solar Array Test

NASA Space Program Now Requires Russian Language

TECH SPACE
China to launch second space lab Tiangong-2 in Q3

China's moon lander Chang'e-3 enters 28th lunar day

Staying Alive on Tiangong 2

China Conducts Final Tests on Most Powerful Homegrown Rocket

TECH SPACE
Scott Kelly returns to earth, but science for NASA's journey to Mars continues

Orbital ATK Completes OA-4 Cargo Delivery Mission to ISS for NASA

Send your computer code into space with astronaut Tim Peake

Black Mold Found in Cargo Prepared for ISS, Resupply Mission Delayed

TECH SPACE
Arianespace Soyuz to launch 2 Galileo satellites in May

SpaceX postpones rocket launch again

Russian rocket engines ban could leave US space program in limbo

SpaceX warns of failure in Wednesday's rocket landing

TECH SPACE
Imaging Technique May Help Discover Earth-Like Planets Around Other Stars

Newly discovered planet in the Hyades cluster could shed light on planetary evolution

Imaging technique may help discover Earth-like planets

Longest-Lasting Stellar Eclipse Discovered

TECH SPACE
Eco-friendly food packaging material doubles shelf-life of food products

Virtual reality is next as smartphone sales slow

Crystal and magnetic structure of multiferroic hexagonal manganite

Mystery of Dracula orchids' mimicry is unraveled with a 3-D printer




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.