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.
Two eruptions a half a world apart have caused evacuations and aviation warnings, but so far no injuries.
The patron animal of quantum theory poses for a unique portrait in which the camera and the sitter don't share a single photon – except by entanglement
The magnitude-6.0 quake that hit California's Napa Valley wasn't the "big one", but it loaded stress on to the Hayward fault close to the Bay Area
NASA explains what the Curiosity rover photographed on Mars after UFO blog raises questions
Bardarbunga, a subglacial stratovolcano, showing increased seismic activity; 2010 eruption caused air travel chaos
A coffee entrepreneur claims his brew is different — and better — than the trendy civet poop coffee. And it starts with the idea that elephants, unlike humans or civets, are herbivores.
Structural colours are more visible and vivid than those that use pigments as many examples from the natural world demonstrate. But sometimes pure white is what is required
Dutch biologist Ingrid van der Meer often meets with disbelief when she talks about her work on dandelions and how it could secure the future of road transport.
Pretend for a minute that it’s 1875 and you’re a mining engineer whose job it is to figure out how much gold is in them thar hills. Get it wrong, and your company is going to waste a lot of time and money hunting for gold that’s not there—or worse yet, miss out on the mother lode
It can only switch from black to transparent and back again, but that's a start