posted on 2023-12-26, 15:06authored byTzia Ming Onn, Kyung-Ryul Oh, Demetra Z. Adrahtas, Jimmy K. Soeherman, Justin A. Hopkins, C. Daniel Frisbie, Paul J. Dauenhauer
Catalytic
condensers composed of ion gels separating a metal electrode
from a platinum-on-carbon active layer were fabricated and characterized
to achieve more powerful, high surface area dynamic heterogeneous
catalyst surfaces. Ion gels comprised of poly(vinylidene difluoride)/1-ethyl-3-methylimidazolium
bis(trifluoromethylsulfonyl) imide were spin coated as a 3.8 μm
film on a Au surface, after which carbon sputtering of a 1.8 nm carbon
film and electron-beam evaporation of 2 nm Pt clusters created an
active surface exposed to reactant gases. Electronic characterization
indicated that most charge condensed within the Pt nanoclusters upon
application of a potential bias, with the condenser device achieving
a capacitance of ∼20 μF/cm2 at applied frequencies
of up to 120 Hz. The maximum charge of ∼1014 |e–| cm–2 was condensed under stable
device conditions at 200 °C on catalytic films with ∼1015 sites cm–2. Grazing incidence infrared
spectroscopy measured carbon monoxide adsorption isobars, indicating
a change in the CO* binding energy of ∼19 kJ mol–1 over an applied potential bias of only 1.25 V. Condensers were also
fabricated on flexible, large area Kapton substrates allowing stacked
or tubular form factors that facilitate high volumetric active site
densities, ultimately enabling a fast and powerful catalytic condenser
that can be fabricated for programmable catalysis applications.