Fruits,vegetables and flowers go deluxe with platinum nanoparticle catalyst

Before getting to the role platinum nanoparticles could play, here’s some information about ripening fruits, vegetables, and flowers, from a May 13, 2013 news item on Nanowerk,

Ripening fruit, vegetables, and flowers release ethylene, which works as a plant hormone. Ethylene accelerates ripening, so other unripened fruit also begins to ripen—fruit and vegetables quickly spoil and flowers wilt.

The news item goes on to describe a new system which could lower or eliminate rapid degradation from ethylene (Note: A link has been removed),

In the journal Angewandte Chemie (“Low-Temperature Oxidation of Ethylene over Platinum Nanoparticles Supported on Mesoporous Silica”), Japanese researchers have now introduced a new catalytic system for the fast and complete degradation of ethylene. This system could keep the air in warehouses ethylene-free, keeping perishable products fresh longer.

The May 13, 2013 article on Wiley’s (Angewandte Chemie publisher) Chemistry Views website, which originated the news item, offers more technical detail about the new system,

Atsushi Fukuoka and his co-workers at Hokkaido University tested different metals in combination with a variety of support materials to develop an effective catalyst. They met with success: Platinum nanoparticles on a support made of special mesoporous silicon dioxide (MCM-41) demonstrated very high activity in the oxidation of ethylene at 0 to 20 °C. At an ethylene concentration of 50 ppm, over 99.8 % conversion was obtained at 0 °C, a previously unattained level that remains steady over longer periods and after multiple uses.

The catalyst is made by stirring the support with an aqueous solution of a platinum salt for 18 hours. The support is then dried and heated first under oxygen and then under hydrogen. After this process, the large pores of the silicon dioxide material contain platinum particles with a size of about 2.4 nm. This particle size, as well as the effect of the silica, seem to be particularly favorable for the reaction.

It is proposed that ethylene (C2H4) and oxygen initially react rapidly on this catalyst to form formaldehyde (HCHO), which is adsorbed onto the platinum and then primarily degraded to carbon monoxide (CO) and hydrogen species that in turn react with oxygen species to make carbon dioxide and water. A small amount of formic acid is formed as a byproduct. The especially high activity of the catalyst results from the facile oxidation of CO to CO2 that occurs at platinum on silicon dioxide supports. The precise details of the reaction mechanism are currently under investigation.

For those who are interested, here are two links to (more or less, there”s more clicking ahead) and a citation for the researchers’ paper,

I believe this paper is behind a paywall.

There is at least one other nanotechnology project devoted to reducing/eliminating food wastage as I noted in my India, Sri Lanka, and Canada team up for nanotechnology-enabled food packaging posting of June 21, 2012. I did get a bit more information about this project (Prof. Jayasankar Subramanian’s at Canada’s University of Guelph is one of the principal investigators) and included it in my Nov. 1, 2012 posting.

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