Insight into Mo2C Nanoplates Growth by Means of Scanning Electrochemical Cell Microscopy for High-Resolution Electrocatalytic Hydrogen Evolution Activity Mapping
Authors/Creators
- 1. Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätstr. 150, 44780 Bochum, Germany
- 2. Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802 USA
- 3. Department of Physics, The Pennsylvania State University, University Park, PA, 16802 USA
Description
Molybdenum carbides have emerged as promising catalysts for the hydrogen evolution reaction (HER). While numerous studies have investigated synthesis methods, structural properties, and their application, the understanding of their local electrochemical behavior and the correlation between particle size and activity remains elusive. This study addresses this gap by carrying out a comprehensive investigation of the HER activity of well-defined morphologies and sizes of α-Mo2C nanoplates, grown via chemical vapor deposition. Scanning electrochemical cell microscopy (SECCM) is employed for high-resolution HER mapping on flakes with dimensions ranging from 1 μm to 40 μm in lateral size, using SECCM capillaries with ≈130 nm tip diameter. Our findings reveal a significant variability in the HER activity at the subparticle level, suggesting that the heterogeneous activity observed in pristine flakes larger than 10 μm is due to an addition of effects caused by the long-term growth, such as step-edge formation, Mo2C oxidation, and the presence of residual graphene. This study underscores the importance of local characterization of individual Mo2C nanoplates, shedding light on the impact of size-dependence on the HER activity.
Other
This work was supported by the European Innovation Council (EIC) under grant agreement no. 101046742 (MeBattery) supported by the European Union's Horizon Europe research and innovation program, the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (CasCat [833408]), as well as the Deutsche Forschungsgemeinschaft (DFG) in the framework of the CRC247 [388390466]. Furthermore, the work was supported by the CAPES—Alexander von Humboldt Foundation Brazil–Germany Internationalization Program grant no. 88881.699096/2022-01, the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) grant no 400755/2022-0, the Rio de Janeiro State Foundation (FAPERJ—grant nos. E-26/210.296/2022, E-26/201.254/2022, E-26/211.464/2021, and E-26/202.393/2022), the Serrapilheira Institute (grant no R-2012-37959), and the Brazilian Nanocarbon Institute of Science and Technology (INCT/Nanocarbono). We acknowledge the Unwin Group from the University of Warwick for allowing us to adapt their software (WEC-SPM) for our SECCM experiments. M.T., D.E.S., A.J.S., and A.F. acknowledge support from the Basic Office of Science of the Department of Energy under award number DE-SC0018025, Conghang Qu for his help with discussions and the three electrode measurements, and the Materials Characterization Laboratory at the Pennsylvania State University and its staff members.
Open Access funding enabled and organized by Projekt DEAL.
Files
DOI10.1002smsc.202500220.pdf
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