Friday, February 10, 2012

Evolution! Cheap New Catalysts to Replace Expensive Platinum

Chang and his UC Berkeley colleagues worked with a common catalyst, molybdenite, that is less expensive than platinum and of increasing interest as a fuel cell catalyst. Composed of molybdenum and sulfur (MoS2), the material catalyzes reactions like the splitting of water into hydrogen and oxygen only at the edges, where triangles of molybdenum and two sulfur atoms stick out like pennants.

“These edge sites look like little MoSS triangles, and the triangular area does the business,” Chang said.

Using complex organic synthesis techniques, Chang said he and his colleagues created a small carbon framework to hold the MoSS triangle so that “every molecule has a discrete edge site that is a catalytically active unit.”

When lots of these single-molecule catalysts were dumped into acidic water and even seawater, they generated hydrogen for several days without letup.

In future research, Chang hopes to assemble billions of these molecules on a thin, ridged wafer, maximizing the number of catalytic sites for a given volume and boosting ultimate efficiency. _Berkeley
Substitution of less expensive materials and feedstocks in place of more expensive or scarce materials, is the way profits are made in industry and business. Human chemical engineers are reaching more deeply into the structure of molecules, becoming ever more deft at shaping matter in more useful and valued forms. To do this profitably, they need highly effective catalysts in very large quantities. Platinum is a very effective catalyst, but it is a precious metal -- extremely expensive, and hard on a profit line.

Chemists at UC Berkeley have achieved a breakthrough in the design of a new class of cheaper catalysts that promise to replace more expensive platinum.
Catalysts are materials ‑ typically metals ‑ that speed up chemical reactions and are widely used in the synthesis of chemicals and drugs. They also are employed in automobile catalytic converters to change combustion chemicals into less-polluting emissions and in fuel cells to convert water into hydrogen.

The problem with catalysts, however, is that chemical reactions occur only at edges of or defects in the material, while the bulk of the metal – often expensive platinum – is inactive and wasted.

In an article appearing this week in the journal Science, UC Berkeley chemists show how to construct a catalyst composed only of edges and demonstrate that it can catalyze the production of hydrogen from water as readily as the edges and defects in regular catalysts.

“This is a conceptual advance in the way we think about generating hydrogen, a clean burning fuel, from water, a sustainable source,” said Christopher Chang, associate professor of chemistry and Howard Hughes Medical Institute Investigator at UC Berkeley. “Our new catalyst is just first generation, but the research gives us and the community a path forward to thinking about how to increase the density of functional active sites so that molecules and materials can be more effective catalysts.”

At the moment, creating these catalysts in the lab is not cheaper than using traditional catalysts, but efforts by Chang and others to simplify the process and create materials with billions of active sites on a ridged wafer much like a Ruffles potato chip could allow cheaper, commercially viable fuel cell catalysts. _Berkeley
The scientists in the link above discuss producing hydrogen from water, using sunlight and advanced catalysts. Other, perhaps more common uses for new types of catalysts probably include use in conversion of natural gas, coal, and biomass into liquid hydrocarbons and industrial chemicals.

The "clean green" meme has taken over much of politics, academia, and the media, but those who must actually work for a living and get the things done that allow society to continue functioning, understand that "clean green" is just a feel-good meme. For societies to prosper, they must utilise dense forms of energy such as hydrocarbons, nuclear, and pre-densified biomass.

The popular green delusion is destroying Germany and other parts of Europe at this time, and if the Obama energy starvationist regime gets its way, it will try to destroy the US as well. This would be a good time for US and European voters to wake up.



Post a Comment

Subscribe to Post Comments [Atom]

<< Home

Newer Posts Older Posts