Accelerating catalytic chemistry and tuning surface reactions require precise control of the electron density of metal atoms. In this work, nanoclusters of platinum were supported on a graphene sheet within a catalytic condenser device that facilitated electron or hole accumulation in the platinum active sites with negative or positive applied potential, respectively. The catalytic condenser was fabricated by depositing on top of a p-type Si wafer an amorphous HfO2 dielectric (70 nm), on which was placed the active layer of 2-4 nm platinum nanoclusters on graphene. A potential of ±6 V applied to the Pt/graphene layer relative to the silicon electrode moved electrons into or out of the active sites of Pt, attaining charge densities more than 1% of an electron or hole per surface Pt atom. At a level of charge condensation of ±10% of an electron per surface atom, the binding energy of carbon monoxide to a Pt(111) surface was computed via density functional theory to change 24 kJ mol-1 (0.25 eV), which was consistent with the range of carbon monoxide binding energies determined from temperature-programmed desorption (ΔBECO of 20 ± 1 kJ mol-1 or 0.19 eV) and equilibrium surface coverage measurements (ΔBECO of 14 ± 1 kJ mol-1 or 0.14 eV). Impedance spectroscopy indicated that Pt/graphene condensers with potentials oscillating at 3000 Hz exhibited negligible loss in capacitance and charge accumulation, enabling programmable surface conditions at amplitudes and frequencies necessary to achieve catalytic resonance.
|Original language||English (US)|
|Number of pages||15|
|Journal||Journal of the American Chemical Society|
|State||Published - Dec 7 2022|
Bibliographical noteFunding Information:
This work was supported as part of the Center for Programmable Energy Catalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences at the University of Minnesota under award #DE-SC0023464. S.R.G. was supported by a Graduate Research Fellowship under Grant CON-75851, project 00074041. This research used resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility located at Lawrence Berkeley National Laboratory, operated under Contract No. DE-AC02-05CH11231. S.P.S.S. and L.C.G. acknowledge the use of the Opuntia, Sabine, and Carya Clusters provided by the Research Computing Data Core at the University of Houston. We thank Jimmy K Soeherman and Xinyu Li for the helpful discussion related to infrared spectroscopy. We also thank Keith and Amy Steva for their generous support of this project through their donor advised fund.
© 2022 American Chemical Society.
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- Journal Article