Researchers at Chiba University in Japan have discovered that not only is caffeine good for recharging tired humans, but it can also be used to enhances the efficiency of fuel cells by increasing the activity of the oxygen reduction reaction.
From time to time I come across stories that have little or nothing to do with printing but are interesting from a manufacturing point of view. And anything to do with generating clean energy is always going to be interesting for most readers. That includes fuel cells, which offer an environmentally friendly form of energy as the world looks to move away from fossil fuels. Essentially a fuel cell is made up of an anode and a cathode separated by an electrolyte. Fuel, such as hydrogen, is added to the anode, while an oxidant, typically oxygen from the air, is introduced at the cathode. In a hydrogen fuel cell, hydrogen undergoes oxidation at the anode, producing hydrogen ions and electrons. The ions move through the electrolyte to the cathode, and electrons flow through an external circuit, generating electricity. At the cathode, oxygen combines with the hydrogen ions and electrons, resulting in water as the sole byproduct.
The problem with this is that water affects the performance of the fuel cell. It reacts with the platinum (Pt) catalyst, forming a layer of platinum hydroxide (PtOH) on the electrode, which obstructs the efficient catalysis of the oxygen reduction reaction (ORR), leading to reduced energy and overall efficiency. The obvious way around this is to use a high Pt loading, but this significantly pushes up the costs of the fuel cells.
However, a team of researchers from the Graduate School of Engineering at Chiba University, Japan, including Professor Nagahiro Hoshi, along with Masashi Nakamura, Ryuta Kubo, and Rui Suzuki, discovered that adding caffeine to certain platinum electrodes can increase the activity of the ORR. This discovery has the potential to reduce platinum requirements, making fuel cells more affordable and efficient.
The idea is that the caffeine adsorbs onto the electrode’s surface, effectively preventing hydrogen adsorption and the formation of Pt oxide on the electrode. The degree of the caffeine’s effectiveness depends on the orientation of the platinum atoms on the electrode’s surface.
In general, fuel cells can generate power as long as fuel is supplied, making them suitable for various applications, including vehicles, buildings, and space missions. This new method has the potential to improve the designs of fuel cells and lead to their widespread use.
Prof. Hoshi noted: “Caffeine, one of the chemicals contained in coffee, enhances the activity of a fuel cell reaction 11-fold on a well-defined Pt electrode of which atomic arrangement has a hexagonal structure.”
He explained: “The increased ORR activity of Pt(111) and Pt(110) was attributed to the decreased PtOH coverage and lower steric hindrance of the adsorbed caffeine. Conversely, for Pt(100), the effect of decreasing PtOH was counteracted by the steric hindrance of the adsorbed caffeine, and thus caffeine did not affect the ORR activity.”
The original paper detailing this research was entitled Enhanced oxygen reduction reaction on caffeine-modified platinum single-crystal electrodes, and was published in the journal Communications Chemistry. You can find further information from Chiba university.
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