Professor Robert Baker

Professor Robert Baker
Department of Chemistry and Biochemistry
The Ohio State University
Printable Abstract

Visualizing Charge and Spin Dynamics at Catalytic Interfaces

At the heart of many energy conversion technologies is the need to control charge and spin transport in systems that are far from equilibrium. This can never be accomplished without the ability to directly observe chemical dynamics at interfaces on the ultrafast time scale of electron motion. Toward this goal, we employ high harmonic generation to produce extreme ultraviolet (XUV) light with femtosecond to attosecond pulse durations. Like X-ray absorption, XUV spectroscopy is element-specific, allowing us to track ultrafast electron motion in complex materials using a tabletop light source. To extend this exciting tool to the study of catalytic interfaces, we have recently pioneered XUV reflection to serve as a surface sensitive analog of X-ray transient absorption.1 This technique now enables direct observation of charge and spin transport at surfaces with unprecedented chemical state specificity. As an example, using this technique to study yttrium iron garnet (Y3Fe5O12) reveals how spin polarized electron transport in this magnetic semiconductor leads to an order of magnitude increase in the photocurrent density for water splitting compared to widely studied hematite (α-Fe2O3).2 To complement XUV measurements, our group also employs sum frequency generation to study interfacial electric fields and ion solvation at electrochemical interfaces.3 These measurements provide molecular insights into how cation solvation controls the interfacial electric field and how these effects mediate the activity and selectivity of electrochemical systems.4,5 This talk will describe how together, these experiments enable new understanding of the molecular features of interfaces that control important energy conversion reactions such as CO2 reduction and water oxidation.

1. S. Biswas, and L. R. Baker, “Extreme Ultraviolet Reflection-Absorption Spectroscopy: Probing Dynamics at Surfaces from a Molecular Perspective,” Accounts of Chemical Research, 2022, 55, 893–903. 
2. H. Gajapathy, S. Bandaranayake, E. Hruska, A. Vadakkayil, B. P. Bloom, S. Londo, J. McClellan, J. Guo, D. Russel, F. M. F. de Groot, F. Yang, D. H. Waldeck, M. Schultze, and L. R. Baker, “Spin Polarized Electron Dynamics Enhance Water Splitting Efficiency by Yttrium Iron Garnet Photoanodes: A New Platform for Spin Selective Photocatalysis,” Chemical Science, 2024, 15, 3300–3310. 
3. J. Rebstock, Q. Zhu, and L. R. Baker, “Exploring the Influence of Interfacial Solvation on Electrochemical CO2 Reduction Using Plasmon-Enhanced Vibrational Sum Frequency Generation Spectroscopy,” ChemCatChem, 2024, 16, e202301301. 
4. Q. Zhu, S. Wallentine, G-H. Deng, J. Rebstock, and L. R. Baker, “Solvation-Induced Onsager Reaction Field Rather than Double Layer Field Controls CO2 Reduction Kinetics on Gold,” JACS Au, 2022, 2, 472–482. 
5. Q. Zhu, C. L. Rooney, H. Shema, C. Zheng, J. A. Panetier, E. Gross, H. Wang, and L. R. Baker, “The Solvation Environment of Molecularly Dispersed Cobalt Phthalocyanine Determines Methanol Selectivity During Electrocatalytic CO2 Reduction,” Nature Catalysis, 2024, 7, 987–999.

Robert Baker

Dr. Robert Baker received his B.S. degree from Brigham Young University in 2007 and his Ph.D. from the University of California, Berkeley in 2012. Following a postdoctoral fellowship with Stephen Leone, he joined The Ohio State University in 2014. His awards include the Camille Dreyfus Teacher-Scholar Award, Coblentz Award in Molecular Spectroscopy, Emerging Leader in Atomic Spectroscopy, Young Innovator Award in NanoEnergy, Journal of Physical Chemistry/ PHYS Division Lectureship, DOE Early Career Award, and AFOSR Young Investigator Award. Baker was the John von Neumann Distinguished Fulbright Fellow to Hungary in 2023 where he performed research at the Extreme Light Infrastructure Attosecond Light Pulse Source. He is the founding director of the NSF National eXtreme Ultrafast Science (NeXUS) Facility. His research focuses on developing spectroscopic tools to probe charge, spin, and solvent dynamics at catalytic interfaces. In addition to research, he is enthusiastic about teaching and mentoring the next generation of scientific leaders.

Hosted by Professor Renee Frontiera