Atomic-resolution imaging as a mechanistic tool for studying single-site heterogeneous catalysis

Yosi Kratish; Yiqi Liu; Jiaqi Li; Anusheela Das; Leighton O. Jones; Amol Agarwal; Qing Ma; Michael J. Bedzyk; George C Schatz; Takayuki Nakamuro; Eiichi Nakamura; Tobin Jay Marks

doi:10.1016/j.chempr.2025.102541

Atomic-resolution imaging as a mechanistic tool for studying single-site heterogeneous catalysis

Yosi Kratish^*, Yiqi Liu, Jiaqi Li, Anusheela Das, Leighton O. Jones, Amol Agarwal, Qing Ma, Michael J. Bedzyk^*, George C Schatz^*, Takayuki Nakamuro^*, Eiichi Nakamura^*, Tobin Jay Marks^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

Heterogeneous catalysts dominate the chemical industry but, unlike homogeneous catalysts, typically feature diverse, incompletely defined active sites. Thus, describing their structure-activity relationships remains challenging. In contrast, molecularly defined single-site heterogeneous catalysts (SSHCs) are poised to address these challenges and provide new avenues for catalysis research and development. The present study explores eco-friendly H₂ production mediated by discrete MoO₂ sites supported on carbon nanohorns (CNHs) and active for alcohol dehydrogenation. Although informative, detailed extended X-ray absorption fine structure (EXAFS), X-ray absorption near-edge structure (XANES), X-ray photoelectron spectroscopy (XPS,) kinetic measurements, and density functional theory (DFT) analysis alone cannot provide a full molecular picture of the reaction pathway. Here, using single-molecule atomic-resolution time-resolved electron microscopy (SMART-EM), we propose the identification of four key catalytic intermediates anchored to CNHs and uncover a new reaction pathway involving alkoxide/hemiacetal equilibration and acetal oligomerization. These intermediates are inferred through a combination of theory and SMART-EM, showcasing the potential of SMART-EM as a complementary tool for exploring mechanistic hypotheses in catalysis.

Original language	English (US)
Article number	102541
Journal	Chem
DOIs	https://doi.org/10.1016/j.chempr.2025.102541
State	Accepted/In press - 2025

Funding

Financial support was provided by the Basic Energy Sciences Program of the US Department of Energy Office of Science (DOE DE-FG02-03ER15457 to the Institute for Catalysis in Energy Processes [ICEP] and DOE DE-SC0024448 to Northwestern University [NU]). This work made use of the NU Integrated Molecular Structure Education and Research Center facilities (supported by the Soft and Hybrid Nanotechnology Experimental [SHyNE] Resource [NSF ECCS-2025633], the International Institute of Nanotechnology, and NU), the NUQuantitative Bio-element Imaging Center (supported by NASA Ames Research Center grant NNA04CC36G), the REACT Facility of NU's Center for Catalysis and Surface Science (supported by DOE grant DE-SC0001329), and the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) 5BM-D beamline at the Advanced Photon Source (APS). The DND-CAT is supported by NU, DuPont de Nemours, and the Dow Chemical Company, and the APS is supported by the DOE at Argonne National Laboratory (contract no. DE-AC02-06CH11357). This research was supported in part by the computational resources and staff contributions provided by the NU Quest High-Performance Computing Facility, which is jointly supported by the Office of the Provost, the Office for Research, and NU Information Technology. This research was also supported by JSPS KAKENHI (JP19H05459, JP23H04874, and 24H00447), the JST PRESTO program (JPMJPR23Q6), and the Kao Foundation for Arts and Science. Financial support was provided by the Basic Energy Sciences Program of the US Department of Energy Office of Science ( DOE DE-FG02-03ER15457 to the Institute for Catalysis in Energy Processes [ICEP] and DOE DE-SC0024448 to Northwestern University [NU]). This work made use of the NU Integrated Molecular Structure Education and Research Center facilities (supported by the Soft and Hybrid Nanotechnology Experimental [SHyNE] Resource [ NSF ECCS-2025633 ], the International Institute of Nanotechnology, and NU), the NU Quantitative Bio-element Imaging Center (supported by NASA Ames Research Center grant NNA04CC36G ), the REACT Facility of NU\u2019s Center for Catalysis and Surface Science (supported by DOE grant DE-SC0001329 ), and the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) 5BM-D beamline at the Advanced Photon Source (APS). The DND-CAT is supported by NU , DuPont de Nemours , and the Dow Chemical Company , and the APS is supported by the DOE at Argonne National Laboratory (contract no. DE-AC02-06CH11357 ). This research was supported in part by the computational resources and staff contributions provided by the NU Quest High-Performance Computing Facility, which is jointly supported by the Office of the Provost , the Office for Research , and NU Information Technology . This research was also supported by JSPS KAKENHI ( JP19H05459 , JP23H04874 , and 24H00447 ), the JST PRESTO program ( JPMJPR23Q6 ), and the Kao Foundation for Arts and Science .

Keywords

catalytic mechanism
density functional theory
electron microscopy
green hydrogen production
molybdenum
SDG7: Affordable and clean energy
single-site heterogeneous catalyst
time-resolved electron microscopy

ASJC Scopus subject areas

General Chemistry
Biochemistry
Environmental Chemistry
General Chemical Engineering
Biochemistry, medical
Materials Chemistry

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1016/j.chempr.2025.102541

Cite this

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title = "Atomic-resolution imaging as a mechanistic tool for studying single-site heterogeneous catalysis",

abstract = "Heterogeneous catalysts dominate the chemical industry but, unlike homogeneous catalysts, typically feature diverse, incompletely defined active sites. Thus, describing their structure-activity relationships remains challenging. In contrast, molecularly defined single-site heterogeneous catalysts (SSHCs) are poised to address these challenges and provide new avenues for catalysis research and development. The present study explores eco-friendly H2 production mediated by discrete MoO2 sites supported on carbon nanohorns (CNHs) and active for alcohol dehydrogenation. Although informative, detailed extended X-ray absorption fine structure (EXAFS), X-ray absorption near-edge structure (XANES), X-ray photoelectron spectroscopy (XPS,) kinetic measurements, and density functional theory (DFT) analysis alone cannot provide a full molecular picture of the reaction pathway. Here, using single-molecule atomic-resolution time-resolved electron microscopy (SMART-EM), we propose the identification of four key catalytic intermediates anchored to CNHs and uncover a new reaction pathway involving alkoxide/hemiacetal equilibration and acetal oligomerization. These intermediates are inferred through a combination of theory and SMART-EM, showcasing the potential of SMART-EM as a complementary tool for exploring mechanistic hypotheses in catalysis.",

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author = "Yosi Kratish and Yiqi Liu and Jiaqi Li and Anusheela Das and Jones, {Leighton O.} and Amol Agarwal and Qing Ma and Bedzyk, {Michael J.} and Schatz, {George C} and Takayuki Nakamuro and Eiichi Nakamura and Marks, {Tobin Jay}",

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doi = "10.1016/j.chempr.2025.102541",

language = "English (US)",

journal = "Chem",

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AU - Kratish, Yosi

AU - Liu, Yiqi

AU - Li, Jiaqi

AU - Das, Anusheela

AU - Jones, Leighton O.

AU - Agarwal, Amol

AU - Ma, Qing

AU - Bedzyk, Michael J.

AU - Schatz, George C

AU - Nakamuro, Takayuki

AU - Nakamura, Eiichi

AU - Marks, Tobin Jay

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AB - Heterogeneous catalysts dominate the chemical industry but, unlike homogeneous catalysts, typically feature diverse, incompletely defined active sites. Thus, describing their structure-activity relationships remains challenging. In contrast, molecularly defined single-site heterogeneous catalysts (SSHCs) are poised to address these challenges and provide new avenues for catalysis research and development. The present study explores eco-friendly H2 production mediated by discrete MoO2 sites supported on carbon nanohorns (CNHs) and active for alcohol dehydrogenation. Although informative, detailed extended X-ray absorption fine structure (EXAFS), X-ray absorption near-edge structure (XANES), X-ray photoelectron spectroscopy (XPS,) kinetic measurements, and density functional theory (DFT) analysis alone cannot provide a full molecular picture of the reaction pathway. Here, using single-molecule atomic-resolution time-resolved electron microscopy (SMART-EM), we propose the identification of four key catalytic intermediates anchored to CNHs and uncover a new reaction pathway involving alkoxide/hemiacetal equilibration and acetal oligomerization. These intermediates are inferred through a combination of theory and SMART-EM, showcasing the potential of SMART-EM as a complementary tool for exploring mechanistic hypotheses in catalysis.

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KW - density functional theory

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KW - molybdenum

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KW - time-resolved electron microscopy

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Atomic-resolution imaging as a mechanistic tool for studying single-site heterogeneous catalysis

Abstract

Funding

Keywords

ASJC Scopus subject areas

UN SDGs

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