Spinach: Good for Popeye and the planet
Chemistry experiments show potential to power fuel cells

Date:
October 5, 2020
Source:
American University
Summary:
Spinach, when converted from its leafy, edible form into carbon
nanosheets, acts as a catalyst for an oxygen reduction reaction
in fuel cells and metal-air batteries.



FULL STORY ==========================================================================
"Eat your spinach," is a common refrain from many people's
childhoods. Spinach, the hearty, green vegetable chock full of nutrients, doesn't just provide energy in humans. It also has potential to help power
fuel cells, according to a new paper by researchers in AU's Department
of Chemistry. Spinach, when converted from its leafy, edible form into
carbon nanosheets, acts as a catalyst for an oxygen reduction reaction
in fuel cells and metal-air batteries.


==========================================================================
An oxygen reduction reaction is one of two reactions in fuel cells and
metal- air batteries and is usually the slower one that limits the energy output of these devices. Researchers have long known that certain carbon materials can catalyze the reaction. But those carbon-based catalysts
don't always perform as good or better than the traditional platinum-based catalysts. The AU researchers wanted to find an inexpensive and less
toxic preparation method for an efficient catalyst by using readily
available natural resources. They tackled this challenge by using spinach.

"This work suggests that sustainable catalysts can be made for an oxygen reduction reaction from natural resources," said Prof. Shouzhong Zou,
chemistry professor at AU and the paper's lead author. "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. The
catalysts are potentially applicable in hydrogen fuel cells and metal-air batteries." Zou's former post-doctoral students Xiaojun Liu and Wenyue
Li and undergraduate student Casey Culhane are the paper's co-authors.

Catalysts accelerate an oxygen reduction reaction to produce sufficient
current and create energy. Among the practical applications for the
research are fuel cells and metal-air batteries, which power electric
vehicles and types of military gear. Researchers are making progress
in the lab and in prototypes with catalysts derived from plants or
plant products such as cattail grass or rice. Zou's work is the first demonstration using spinach as a material for preparing oxygen reduction reaction-catalysts. Spinach is a good candidate for this work because
it survives in low temperatures, is abundant and easy to grow, and is
rich in iron and nitrogen that are essential for this type of catalyst.

Zou and his students created and tested the catalysts, which are spinach- derived carbon nanosheets. Carbon nanosheets are like a piece of paper
with the thickness on a nanometer scale, a thousand times thinner
than a piece of human hair. To create the nanosheets, the researchers
put the spinach through a multi-step process that included both low-
and high-tech methods, including washing, juicing and freeze-drying
the spinach, manually grinding it into a fine powder with a mortar
and pestle, and "doping" the resulting carbon nanosheet with extra
nitrogen to improve its performance. The measurements showed that the spinach-derived catalysts performed better than platinum-based catalysts
that can be expensive and lose their potency over time.

The next step for the researchers is to put the catalysts from the lab simulation into prototype devices, such as hydrogen fuel cells, to see
how they perform and to develop catalysts from other plants. Zou would
like to also improve sustainability by reducing the energy consumption
needed for the process.


========================================================================== Story Source: Materials provided by American_University. Original written
by Rebecca Basu.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Xiaojun Liu, Casey Culhane, Wenyue Li, Shouzhong
Zou. Spinach-Derived
Porous Carbon Nanosheets as High-Performance Catalysts for Oxygen
Reduction Reaction. ACS Omega, 2020; 5 (38): 24367 DOI: 10.1021/
acsomega.0c02673 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201005122138.htm

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