Oxide catalysts, typically formulated as powders, play an integral role in many chemical transformations, including cleaning wastewater, curbing tailpipe emissions, and synthesizing most consumer products.
Greener, more efficient chemical processes would benefit greatly from solid oxide catalysts that are choosier about their reactants, but achieving this has proven a challenge. Now researchers from Northwestern University and Argonne National Laboratory have developed a straightforward and generalizable process for making reactant-selective oxide catalysts by encapsulating the particles in a sieve-like film that blocks unwanted reactants.
The process could find applications in energy, particularly the conversion of biomass into sugars and then fuels and other useful chemicals.
A paper detailing the research, "Shape-selective Sieving Layers on an Oxide Catalyst Surface," was published October 28 in the journal Nature Chemistry.
Especially for selective oxidation, "The ability to conduct these reactions in a selective way opens doors to new applications in green chemistry and sustainability," said Justin Notestein, assistant professor of chemical and biological engineering at Northwestern's McCormick School of Engineering and the paper's corresponding author. "Unlike current processes, which may require enzymes or precious metals, our method relies only on harmless, inert oxides. These are powders you can hold in your hand."
In testing their method, the researchers focused on photocatalytic oxidations such as the conversion of benzyl alcohol into benzaldehydes, reactions that are notoriously unselective. The researchers coated a core particle of titanium dioxide, a harmless white pigment, with a nanometer-thick film of aluminum oxide. They used a synthesis method that resulted in a film pitted with tiny holes they dubbed "nanocavities," less than two nanometers in diameter.
This sieve-like coating allowed only the smaller reactants in a mixture to slip through the holes and react with the titanium oxide, while larger reactants were blocked. The result was much higher selectivity (up to 9:1) toward the less hindered reactants.
The process was conducted at room temperature and required only a low-power light source, whereas other catalysts may require precious metals or hazardous oxidants.
Northwestern University: http://www.northwestern.edu
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
The state has sent National Guard troops to the town of Pahoa to assist with a road block and security.
Researchers had tried for 23 years to connect this piece of metal to Amelia Earhart's disappearance. They finally think they've proven it was part of her plane.
Michelangelo painted the ceiling of the Sistine Chapel by the light of the sun coming through small windows, and now 450 years after his death, his masterpieces are being seen in a whole new light provided by 7,000 LEDs. The chapel is also getting a new ventilation system. Allen Pizzey reports.
Reports that a passenger photographed a rainbow from her plane are mistaken. The colours are caused by polarisation
Jiri Bruthans created this pillar with simulated salt weathering; in nature (like at Bryce Canyon, below), factors like frost and rain also shape the landscape. Courtesy of Jiri Bruthans Getty Aa the story goes, the iconic spires in Utah's Bryce Canyon National Park once were human-animal “legend people,” until an angry coyote god turned them […]
The discovery of a third type of light associated with dark matter could strengthen the case that we are seeing a signal of the mysterious stuff
The flow, which began at Mount Kilauea in June, threatens to take out dozens of homes on the Big Island.
Written 20 years ago, the first algorithm to tap into the ultra-fast potential of quantum computing has been run on a real machine at long last
Shirley Corriher, author of Cookwise: The Hows and Whys of Successful Cooking, has tips on taking the bitter bite out of coffee, and holding onto cabbage's red hue while it's in the pan.
Data originally taken for another reason weaken the case for "dark photons"