<img src = "https://cdn.arstechnica.net/wp-content/uploads/2020/10/spinachTOP-800×533.jpg" alt = "Popeye reaches for a can of spinach in a still picture of a stranger Popeye Film, c. 1945. American University scientists believe the leafy green has the potential to power future fuel cells. "/>
Enlarge /. Popeye reaches for a can of spinach in a still from an unknown Popeye movie, c. 1945. American University scientists believe the leafy green has the potential to power future fuel cells.
Paramount Pictures / Courtesy of Getty Image
When making efficient fuel cells, everything revolves around the catalyst. A good catalyst leads to faster, more efficient chemical reactions and thus to an increased energy output. Today's fuel cells are typically based on platinum-based catalysts. However, American University scientists believe that spinach – considered a "superfood" for being so rich in nutrients – is an excellent catalyst for renewable carbon atoms, based on their experiments to prove the principle in a recent paper in the journal published articles described were ACS Omega. Popeye would definitely agree.
Spinach has a surprisingly long history in science; The idea of harnessing its photosynthetic and electrochemical properties has been around for about 40 years. Spinach is abundant, cheap, easy to grow, and high in iron and nitrogen. Many (many!) Years ago, as a budding science journalist, I took part in a conference talk by physicist Elias Greenbaum (then with Oak Ridge National Labs) about his spinach research. He was particularly interested in the protein-based "reaction centers" in spinach leaves, which 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 sugars; The other, Photosystem 2 (PS2), splits water to create oxygen. PS1, which acts like a tiny light-sensitive battery, absorbs energy from sunlight and emits electrons with an efficiency of nearly 100 percent, is of great scientific interest. PS1s can generate a light-induced flow of electricity in a fraction of a second.
Granted, it's not a huge amount of power, but it's enough to run small molecular machines one day. Greenbaum's work showed promise in the construction of artificial retinas, for example replacing damaged retinal cells with photosensitive PS1 to restore vision in people with degenerative eye disease. Since PS1s can be tailored to act like diodes and conduct current in one direction but not the other, they could be used to build logic gates for a rudimentary computer processor if they could be connected by molecule-sized wires made from carbon nanotubes .
Greenbaum is just one of many researchers interested in spinach. For example, in 2012, scientists at Vanderbilt University combined PS1s with silicon to produce current levels nearly 1000 times higher than when depositing the protein centers on metals, along with a slight increase in voltage. The goal was to eventually build "biohybrid" solar cells that could compete with standard silicon solar cells in terms of voltage and current.
Spinach also has other interesting properties outside of its reaction centers. For example, Chinese researchers from 2014 reported on experiments to collect activated carbon from spinach for capacitor electrodes. Just last December, another group of Chinese scientists investigated the potential of making spinach-based nanocomposites as photocatalysts.