• Kelsey A. Stoerzinger

    Linus Pauling Distinguished Postdoctoral Fellow at PNNL

  • I am a Linus Pauling Distinguished Postdoctoral Fellow at the Pacific Northwest National Laboratory, working to bring together solar energy and storage by using photons to generate chemical fuels. In September, I join the Chemical Engineering faculty at Oregon State University.

    I’m interested in the fascinating chemistry that occurs at electrochemical interfaces and plays a critical role in dictating performance of catalysts involved in energy conversion and storage. My background is a hybrid of materials science and surface physics, which have coalesced in my use of spectroscopic approaches to link the surface chemistry of catalysts to their electronic structure and performance. This mechanistic understanding can in turn guide the rational design of more active catalysts, increasing the efficiency of electrochemical devices (e.g. fuel cells, electrolyzers). I'm particularly interested in the interface between earth-abundant catalysts, comprised of transition metal oxides, with water -- with further applications in water purification.

  • Research Interests

    Understanding and leveraging surface chemistry to develop materials for energy conversion and storage.

    Photoelectrocatalysis for solar water splitting

    Fundamental studies of semiconductor protection layers and oxide surfaces

    The intermittent nature of renewable energy sources requires a clean, scalable means of converting and storing energy. Photoelectrochemical (PEC) cells based on semiconductor/liquid interfaces can convert sunlight to chemical fuels without external circuitry, such as “splitting” water into O2 and H2 upon illumination. The efficacy of conversion depends in part on the rectifying properties of semiconductor–electrolyte junctions, which drives the separation of electron–hole pairs. Earth abundant oxide materials can be used as photoabsorbers and catalysts, as well as protective coatings for traditional semiconductor absorbers, where ideal band alignment and transport of charge carriers through the heterostructures might enable water splitting without the use of precious metal catalysts. I study the charge transport across these buried solid junctions and at the interface between the oxide and water to better understand the kinetics of PEC conversion. Additionally, I study the absorption and electrocatalytic properties of earth-abundant oxide photoanodes.

     

    Select publications:

    Stoerzinger, K.A. Wang, L. Ye, Y. Bowden, M. Crumlin, E.J. Du, Y. Chambers, S.A. “Linking surface chemistry to photovoltage in Sr-substituted LaFeO3 for water oxidation”. Journal of Materials Chemistry A (2018) DOI: 10.1039/C8TA05741A. link

    Link

    Stoerzinger, K.A. Du, Y. Spurgeon, S.R. Wang, L. Kepaptsoglou, D. Ramasse, Q.M. Crumlin, E.J. Chambers, S.A. “Chemical and Electronic Structure Analysis of a SrTiO3 (001) / p-Ge (001) Hydrogen Evolution Photocathode”. MRS Communications 8 (2018) 446-452. link

    Intrinsic activity of oxide catalysts

    Electrochemical studies of model systems

    In order to rationally design more active catalysts for energy and conversion and storage, thus reducing material cost for commercial technologies, I study the fundamental processes that occur on model catalyst systems for oxygen reduction and evolution. Electrochemical studies of well-defined surfaces grown by pulsed laser deposition or molecular beam epitaxy establish the intrinsic activity of oxide catalysts in a way that cannot be realized with polydisperse nanoparticle systems, and can also reveal how different terminations and structures affect the kinetics. These studies of epitaxial thin films were among the first to probe phenomena that are not straightforward to isolate in nanoparticles, such as the role of oxide band structure, interfacial charge transfer (the “ligand” effect), strain, and crystallographic orientation.

     

    Select publications:

    Stoerzinger, K.A.* Diaz-Morales, O.* Kolb, M. Rao, R.R. Frydendal, R. Qiao, L. Wang, X.R. Bendtsen Halck, N. Rossmeisl, J. Hansen, H.A. Vegge, T. Stephens, I.E.L. Koper, M.T.M. Shao-Horn, Y. “Orientation-dependent oxygen evolution on RuO2 without lattice exchange”. ACS Energy Letters 2 (2017) 876–881. link

     

    Stoerzinger, K.A. Lu, W.M. Li, C. Ariando, Venkatesan, T. Shao-Horn, Y. “Highly Active Epitaxial La(1-x)SrxMnO3 Surfaces for the Oxygen Reduction Reaction: Role of Charge Transfer” J. Phys. Chem. Lett. 6 (2015) 1435-1440. link

     

    Stoerzinger, K.A. Choi, W.S. Jeen, H. Lee, H.N. and Shao-Horn, Y. “Role of Strain and Conductivity in Oxygen Electrocatalysis on LaCoO3 Thin Films” J. Phys. Chem. Lett. 6 (2015) 487-492. link

     

    Stoerzinger, K.A. Risch, M. Suntivich, J. Lu, W.M. Zhou, J. Biegalski, M. Christen, H. Ariando, Venkatesan, T. Shao-Horn, Y. “Oxygen Electrocatalysis on (001)-Oriented Manganese Perovskite Films: Mn Valency and Charge Transfer at the Nanoscale” Energy Environ. Sci. 6 (2013) 1582-1588. link

    • Highlighted in the MIT Materials Processing Center newsletter. link

    Surface chemistry of oxide catalysts

    Spectroscopic probing of surface species in situ

    Ambient pressure X-ray photoelectron spectroscopy is a recent technique which can probe the surface species present in environments approaching that of material operation, bridging the pressure gap between surface science and application. I have used this approach to investigate the adsorption of water on well-defined thin film surfaces at a range of relative humidities, establishing the oxygen speciation and quantifying its dependence on the chemical potential of water. The reactivity with water--specifically it's dissociation to form adsorbed hydroxyl species--depends on both the transition metal of complex oxides and the termination in the ternary perovskite crystal structure. Furthermore, I found that stronger interaction with hyrodroxyls correlates with decreased catalytic activity for oxygen reduction, as well as wetting on a macroscopic scale. This fundamental insight brought molecular understanding to the wetting of oxide surfaces, as well as the role of hydrogen bonding in catalysis.

     

    Select publications:

    Stoerzinger, K.A. Hong, W.T. Wang, X. Rao, R.R. Subramanyam, S.P.B. Li, C. Ariando, Venkatesan, T. Liu, Q. Crumlin, E.J. Varanasi, K.K. Shao-Horn, Y. “Decreasing the Hydroxylation Affinity of La(1-x)SrxMnO3 Perovskites To Promote Oxygen Reduction Electrocatalysis”. Chemistry of Materials 29 (2017) 9990–9997. link

     

    Stoerzinger, K.A. Comes, R. Spurgeon, S.R. Thevuthasan, S. Ihm, K. Crumlin, E.J. Chambers, S.A. “Influence of LaFeO3 Surface Termination on Water Reactivity”. J. Phys. Chem. Lett. 8 (2017) 1038–1043. link

     

    Stoerzinger, K.A. Hong, W.T. Crumlin, E.J. Bluhm, H. Shao-Horn, Y. “Insights into Electrochemical Reactions from Near-Ambient Pressure Photoelectron Spectroscopy” Acc. Chem. Res. 48 (2015) 2976-2983. link

    • Highlighted on the cover. link

    Stoerzinger, K.A. Hong, W.T. Azimi, G. Giordano, L. Lee, Y.-L. Crumlin, E.J. Biegalski, M.D. Bluhm, H. Varanasi, K.K. Shao-Horn, Y. “Reactivity of Perovskites with Water: Role of Hydroxylation in Wetting and Implications for Oxygen Electrocatalysis” J. Phys. Chem. C 119 (2015) 18504-18512. link

    • Highlighted in the MIT news. link
  • Biography

    2010, B.S., Northwestern University, Materials Science and Engineering

    2011, M.Phil., University of Cambridge, Physics (Churchill Scholar)

    2016, Ph.D., Massachusetts Institute of Technology, Materials Science and Engineering (NSF Graduate Research Fellowship)

    2016, Linus Pauling Distinguished Postdoctoral Fellowship, Pacific Northwest National Laboratory

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