Gold–Palladium Bimetallic Catalyst Stability: Consequences for Hydrogen Peroxide Selectivity

Enrico Pizzutilo, Simon J Freakley, Serhiy Cherevko, Sriram Venkatesan, Graham J Hutchings, Christian H Liebscher, Gerhard Dehm, Karl JJ Mayrhofer

Research output: Contribution to journalArticle

26 Citations (Scopus)
34 Downloads (Pure)

Abstract

During application, electrocatalysts are exposed to harsh electrochemical conditions, which can induce degradation. This work addresses the degradation of AuPd bimetallic catalysts used for the electrocatalytic production of hydrogen peroxide (H2O2) by the oxygen reduction reaction (ORR). Potential-dependent changes in the AuPd surface composition occur because the two metals have different dissolution onset potentials, resulting in catalyst dealloying. Using a scanning flow cell (SFC) with an inductively coupled plasma mass spectrometer (ICP-MS), simultaneous Pd and/or Au dissolution can be observed. Thereafter, three accelerated degradation protocols (ADPs), simulating different dissolution regimes, are employed to study the catalyst structure degradation on the nanoscale with identical location (IL) TEM. When only Pd or both Au and Pd dissolve, the composition changes rapidly and the surface becomes enriched with Au, as observed by cyclic voltammetry and elemental mapping. Such changes are mirrored by the evolution of electrocatalytic performances toward H2O2 production. Our experimental findings are finally summarized in a dissolution/structure/selectivity mechanism, providing a clear picture of the degradation of bimetallic catalyst used for H2O2 synthesis.
Original languageEnglish
Pages (from-to)5699-5705
Number of pages7
JournalACS Catalysis
Volume7
Issue number9
DOIs
Publication statusPublished - 11 Jul 2017

Cite this

Pizzutilo, E., Freakley, S. J., Cherevko, S., Venkatesan, S., Hutchings, G. J., Liebscher, C. H., Dehm, G., & Mayrhofer, K. JJ. (2017). Gold–Palladium Bimetallic Catalyst Stability: Consequences for Hydrogen Peroxide Selectivity. ACS Catalysis, 7(9), 5699-5705. https://doi.org/10.1021/acscatal.7b01447