(Invited) Multifunctional Membrane Coated Electrocatalysts

Abstract

Electrocatalysts are essential components in many emerging electrochemical technologies due to their ability to efficiently facilitate the interconversion between electrical and chemical energy. However, significant improvements in the stability, activity, and selectivity of state-of-the-art electrocatalysts must be made if these technologies are going to play a major role in a sustainable energy future. The vast majority of electrocatalysts used in today’s commercial devices are comprised of metallic nanoparticles or thin films that are deposited onto a conductive support and partially exposed to the bulk electrolyte. By contrast, this work has explored an alternate electrocatalyst architecture in which the active electrocatalyst has been encapsulated by an ultrathin permeable overlayer. Specifically, we encapsulate Pt nanoparticle and thin film electrocatalysts with 2-20 nm thick layers of silicon oxide (SiOx) fabricated using a room temperature deposition process.[1] Through a combination of physical characterization and electroanalytical measurements, we show that these permeable overlayers can serve as nano-scale membranes that provide significant benefits for stabilizing Pt nanoparticles and imparting advanced catalytic functionalities such as poison-resistance. This work has focused on SiOx-encapsulated Pt thin films electrocatalysts for the hydrogen evolution reaction, but the membrane coated electrocatalyst architecture also has great potential as a tunable platform that can be extended to many other materials and chemistries. [1] N. Y. Labrador, X. Li, Y. Liu, J. T. Koberstein, R. Wang, H. Tan, T. P. Moffat, and D. V. Esposito, Nano Letters, 16, 6452-6459, 2016.