<p>The high Pt loading required for hydrogen oxidation
(HOR) and evolution (HER) reactions in alkaline fuel cells and electrolyzers
adversely impacts the system cost. Here, we demonstrate the use of caffeine as
a ‘double-layer dopant’ to enhance both the HER and HOR of Pt electrodes in
base. HER/HOR rates increase by fivefold on Pt(111) and are accelerated on
Pt(110), Pt(pc), and Pt/C as well. FTIR spectroscopy confirms that caffeine is
adsorbed at the Pt surface, forming a self-limiting film through
electrochemical deposition. Caffeine films are stable up to 1.0 V vs. RHE and
are readily regenerated through caffeine deposition during load/potential
cycling. The findings presented here both identify a potential catalyst
additive that can mitigate high Pt loadings in alkaline fuel cells and
electrolyzers while opening the door to molecular engineering of solid/liquid
interfaces for energy storage and conversion.</p>
Caffeinated Interfaces Enhance Alkaline Hydrogen Electrocatalysis