PS1s have also shown promise as catalysts in fuel cell technology. (The patented Greenbaum took early use of spinach as a catalyst that involves spraying metallic platinum on PS1s to produce pure hydrogen gas to power fuel cells.) The leafy green could be a less toxic and cheaper catalyst for the oxygen-reducing reaction in fuel cells, according to the authors of this paper Last.

Its extraction process is similar to the one Greenbaum used all those past years. It starts with a common kitchen mixer, filled with freshly washed spinach leaves and then mashed. The resulting juice was dried and ground into a fine powder with a mortar and pestle. Next, the university team added salts (sodium chloride and potassium chloride) and a dash of melamine to boost the nitrogen content. “at this point, [our method] It requires us to add a little bit of nitrogen to the starting material, because though [spinach] It has a lot of nitrogen to start with, during the preparation process, some of that nitrogen is lost, ”co-author ShouZhong Zou, professor of chemistry at American University, Spectrum said.

The salts are essential for the production of pores in the final nanoparticles, thus increasing the surface area available for optimizing chemical reactions. “Although we call them nanoscale sheets, when they are stacked together, they don’t look like a pile of very stiff paper,” Zou explained To the spectrum. “We need to make it breathable enough so that all active sites can be used.”

Finally, the AU team used two rounds of the Pyrolysis (Pyrolysis process) at temperatures of 900 ° C to produce nanoparticles.

They found that the catalysts derived from spinach were more efficient than the platinum-based catalysts. “This work indicates the possibility of creating sustainable catalysts for the oxygen-reducing reaction from natural resources,” Zou said. “The method we tested can produce highly active, carbon-based catalysts from spinach, which is a renewable biomass. In fact, we believe it outperforms commercial platinum catalysts in both activity and stability.”

This is clearly just a proof of principle. What works well in an ideal laboratory environment does not necessarily translate easily into real-world practical application. The next step is to build a complete prototype that uses the spinach-based catalyst in an actual hydrogen fuel cell. According to Zhou, this will require collaboration with other laboratories. Spinach can also be a good catalyst for the metal air batteries used to power electric vehicles.

DOI: ACS Omega, 2020. 10.1021 / acsomega.0c02673 (About DOIs).