Caffeine Makes Fuel Cells More Efficient, Cuts Cost of Energy Storage
To maintain efficient operation, fuel cells require a high Pt loading (greater platinum content), which significantly ups the costs of fuel cells. A quick look online found market prices for platinum of $29.98 per gram, or $932.61 per ounce, at the time of writing. The researchers found that adding caffeine can improve the ORR activity of platinum electrodes 11 fold, making the reaction more efficient. If you are wondering (as we were) how they came to be experimenting with this, the paper explains that modifying electrodes with hydrophobic material is known to be an effective method for enhancing ORR. Caffeine is less toxic than other hydrophobic substances, and it activates the hydrogen evolution and oxidation reactions of Pt nanoparticles and caffeine doped carbons. Got that?
Chiba University’s work was led by Professor Nagahiro Hoshi at the Department of Applied Chemistry and Biotechnology. He explained that the researchers found a notable improvement in the electrode’s ORR activity with an increase in caffeine concentration in the electrolyte. This forms a thin layer on the electrode’s surface, effectively preventing the formation of PtOH, but the effect depends on the orientation of the platinum atoms on the electrode’s surface. The paper refers to these as Pt(100), Pt(110) and Pt(111), with the latter two showing increased ORR activity, while there was no noticeable effect with Pt(100). The researchers do not explain if this latter effect might be a problem, but instead claim that their discovery has the potential to improve the designs of fuel cells and lead to more widespread adoption.
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