Active electrocatalysts that are encapsulated by ultrathin semi-permeable overlayers represent an emerging class of catalysts that offer the potential to improve electrocatalyst stability, activity, and selectivity.[1] Such overlayers offer new control knobs to alter electrocatalytic activity and/or selectivity through their ability to influence species transport to active sites and confinement effects at the catalytically active buried interface.[1,2] In the current study, we have deposited 5-10 nm thick continuous layers of silicon oxide containing varying carbon content (SiOxCy) onto well-defined electrocatalytic Pt thin films using a low temperature ultraviolet Ozone (UV-Ozone) process. After characterizing the physical and chemical properties of these electrodes, the basic electrochemical and electrocatalytic properties of the SiOxCy|Pt electrodes were evaluated using a variety of electroanalytical techniques. CO stripping voltammetry measurements reveal that the energetics at the buried interface depend strongly on the carbon content in the SiOxCy overlayers, consistent with varied activity of the SiOxCy|Pt electrodes towards the oxidation of small alcohols. We find that encapsulated electrodes exhibit a factor of 2-3 times increase in peak alcohol oxidation current density compared to bare Pt, with maximum performance being observed when overlayers contain intermediate levels of carbon. In this talk, I will describe the origin of the optimal overlayer composition and highlight opportunities to extend this knowledge to other materials and electrocatalytic reactions.

Tuning the electrocatalytic properties of platinum electrodes by encapsulation with ultrathin SiOxCy coatings

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.