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Nanometer Scale Spectroscopic Visualization of Catalytic Sites During a Hydrogenation Reaction on a Pd/Au Bimetallic Catalyst

preprint
revised on 03.09.2020 and posted on 03.09.2020 by hao yin, Liqing Zheng, Wei Fang, Yin-Hung Lai, Nikolaus Porenta, Guillaume Goubert, Hua Zhang, Hai-Sheng Su, Bin Ren, Richardson O. Jeremy, Jian-Feng Li, Renato Zenobi

Understanding the mechanism of catalytic hydrogenation at the local environment requires chemical and topographic information involving catalytic sites, active hydrogen species and their spatial distribution. Here, tip-enhanced Raman spectroscopy (TERS) was employed to study the catalytic hydrogenation of chloro-nitrobenzenethiol on a well-defined Pd(sub-monolayer)/Au(111) bimetallic catalyst (pH2=1.5 bar, 298 K), where the surface topography and chemical fingerprint information were simultaneously mapped with nanoscale resolution (≈10 nm). TERS imaging of the surface after catalytic hydrogenation confirms that the reaction occurs beyond the location of Pd sites. The results demonstrate that hydrogen spillover accelerates hydrogenation at the Au sites within 20 nm from the bimetallic Pd/Au boundary. Density functional theory was used to elucidate the thermodynamics of interfacial hydrogen transfer. We demonstrate that TERS as a powerful analytical tool provides a unique approach to spatially investigate the local structure-reactivity relationship in catalysis.

Funding

grant # 741431 - 2DNanoSpec

grants # 21925404, 21775127, and 21703181

grant # EG22‐122016

project # 175696

The Fundamental Research Funds for the Central Universities (20720190044) and MOST (2019YFA0705402)

History

Email Address of Submitting Author

liqing.zheng@org.chem.ethz.ch

Institution

ETH Zurich

Country

Switzerland

ORCID For Submitting Author

0000-0001-7848-6985

Declaration of Conflict of Interest

The authors declare no competing interests

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