Tracking the Dynamics of a Ag-MnOx Oxygen Reduction Catalyst Using In Situ and Operando X-ray Absorption Near-Edge Spectroscopy
Sustainable electricity generation via hydrogen fuel cells requires the development of efficient oxygen reduction reaction (ORR) catalysts. In situ/operando experiments are necessary to uncover the extent of dynamic material changes during catalysis. Herein, we use in situ/operando X-ray absorption...
Saved in:
Published in | ACS energy letters Vol. 8; no. 7 |
---|---|
Main Authors | , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society (ACS)
14.07.2023
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Sustainable electricity generation via hydrogen fuel cells requires the development of efficient oxygen reduction reaction (ORR) catalysts. In situ/operando experiments are necessary to uncover the extent of dynamic material changes during catalysis. Herein, we use in situ/operando X-ray absorption near-edge spectroscopy to track Mn valence changes of a promising, ultrathin, porous MnOx layer on a Ag thin film. Mn–K-edge measurements as a function of electrochemical environment and ORR conditions reveal that, interestingly, when driving the ORR at 0.8 VRHE, the Mn is distinctively more reduced and the MnOx redox is nonreversible in contrast to measurements in N2-saturated electrolyte. Ex situ inductively coupled plasma mass spectrometry, atomic force microscopy, and X-ray photoelectron spectroscopy indicate that these phenomena do not correlate to metal dissolution but might be associated with morphological surface reconstruction related to Ag valency. Furthermore, this study highlights how the microenvironment and catalysis play a key role in the in situ/operando surface structure and chemical state. |
---|---|
Bibliography: | USDOE Office of Science (SC), Basic Energy Sciences (BES) AC02-76SF00515; 1650114 USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB) National Science Foundation Graduate Research Fellowship |
ISSN: | 2380-8195 2380-8195 |
DOI: | 10.1021/acsenergylett.3c00823 |