Popeye will allow: Spinach can hold key to renewable fuel cell catalysts

Popeye reaches for a can of spinach in a still from an unidentified <em data-recalc-dims=Popeye Film, c. 1945. Scientists at American University believe that leafy greens help fuel future fuel cells. “/>
Zoom in / Popeye reaches out to a stranger for a spinach in a stable Popeye Film, c. 1945. Scientists at the American University believe that leafy greens help fuel future fuel cells.

Courtesy of Paramount Pictures / Getty Images

When it comes to building efficient fuel cells, it’s all about the catalyst. A catalytic result will result in faster, more efficient chemical reactions and, thus, an increase in energy release output. Today’s fuel cells generally rely on platinum-based catalysts. But scientists at American University believe that spinach is considered a “superfood” because it is rich in nutrients – based on their proof-of-principle experiments described in a recent paper published in the journal, it will become an excellent renewable carbon-rich catalyst. ACS Omega. Popeye will definitely allow.

The idea of ​​absorbing the photosynthetic properties of spinach has been around for about 40 years. Spinach is plentiful, inexpensive, easy to grow and rich in iron and nitrogen. Many (many!) Years ago, as a budding young science writer, I attended a conference discussion of physicist Eli Lias Greenbum (then with Oak Ridge National Labs) about his research on spinach. In particular, he was interested in the protein-based “reaction centers” in spinach leaves that are the basic mechanism for photosynthesis – the chemical process by which plants convert carbon dioxide into oxygen and carbohydrates.

There are two types of reaction centers. One type, known as Photosystem 1 (PS1), converts carbon dioxide into sugar; The other, Photosystem 2 (PS2), splits water to produce oxygen. Most of the scientific interest is in the PS1, which acts like a small photosensitive battery, absorbs energy from sunlight and emits electrons with almost 100 percent efficiency. In essence, energy from sunlight converts water into oxygen molecules, positively charged hydrogen ions, and free electrons. These three molecules then combine to form the sugar molecule. The PS1 is capable of producing a light-excited stream of electricity in a fraction of a second.

Granted, that is not a large amount of power, but one day is enough to run small molecular machines. Greenbum’s work promises to create artificial retinas, for example, to restore vision in people suffering from degenerative conditions of the eye by replacing damaged retinal cells with light-sensitive PS1s. The PS1 behaves like diodes, passing current in one direction but not the other, so if one could connect them via atom-sized wires made of carbon nanotubes, they could be used to make logic gates for early computer processors. .

Greenbum is one of the many researchers who are interested in the electrochemical properties of spinach. For example, in 2012, scientists at the University of Wrttemberg combined PS1s with silicon to obtain 1000 times more than when they were deposited at current levels of protein centers on metals, with a slight increase in voltage. The goal was ultimately to create “biohybrid” solar cells that could compete with standard silicon solar cells in terms of voltage and current levels. A 2014 paper by Chinese researchers reported on experiments to collect activated carbon from spinach for capacitor electrodes, while last December, another group of Chinese scientists examined the possibility of creating spinach-based nanoparticles to serve as photot at lists.