Research Focus

“Life at the edge” - Surfaces are where the action is!

Our research involves investigating and understanding chemical reactions at surfaces. Interfacial processes and surface chemistry are at the heart of a wide range of technologies, including those associated with the chemical and petroleum industries, functioning of batteries and fuel cells, production of microelectronic devices, and design and fabrication of sensors and diagnostic devices. Surfaces play key roles in heterogeneous processes in environmental and atmospheric chemistry. By discovering novel methods to alter and control surface chemistry, we seek to develop new catalysts for specialty chemical synthesis, make advanced materials with novel properties, and build functional nanostructures. Surfaces are central to nanoscience and technology, modifying and controlling important properties of nanoparticles and electrical contacts. We employ a wide array of surface analytical techniques in our work, including ultrahigh vacuum (UHV) scanning tunneling microscopy (STM), high-resolution X-ray photoelectron spectroscopy (HR-XPS), low energy ion scattering (LEIS), and infrared reflection-absorption spectroscopy (IRAS).

Acetylene adsorption modes and reactions on Pt catalytic surfaces can be controlled by alloying with Sn. The presence of Sn decreases the adsorption energy of acetylene and suppresses acetylene decomposition, which makes associative reactions forming dimers (C4 hydrocarbons) and trimers (benzene) progressively more energetically favorable with increasing Sn concentration. Taken from J. Gao, H. Zhao, X. Yang, B. E. Koel, S. G. Podkolzin, ACS Catal., 3, 1149-53 (2013)

Current research activities include:

(i) Heterogeneous catalysis— structure and chemistry of alloy and oxide films at bimetallic Pt surfaces, understanding active sites and improving heterogeneous catalysts for olefin metathesis, fundamentals of biomass upgrading to fuels and chemicals over catalytic bimetallic nanoparticles, investigation of Rh nanoparticle oxidation states during bio-fuel reforming, plasma processing of clean next-generation fuels, plasmon-enabled chemistry

(ii) Photoelectrocatalysis — synthesis and characterization of novel photocatalysts for solar water splitting and carbon dioxide reduction to fuels, surface chemistry of hematite-based photoanodes for solar water splitting, establishing the role of the electrode surface in solar-driven pyridine-catalyzed CO2 reduction

(iii) Electrochemistry — novel alloy electrodes for fuel cells, in-situ high-resolution studies of the solid electrolyte interphase layer in batteries

(iv) Environmental chemistry — heavy metal sequestration and remediation by core-shell iron nanoparticles, reactions at iron-enriched mineral interfaces and implications for catalytic oxidation of aqueous contaminants

(v) Plasma-surface interactions — fundamental studies of reactive processes at plasma-surface interfaces, i.e., reactions of atoms, radicals, and ions at surfaces, liquid metals as plasma-facing materials for fusion energy systems, fundamental studies of deuterium retention in solid and liquid metals, surface science of plasma-facing components (PFCs) for improved plasma performance in the National Spherical Torus Experiment-Upgrade (NSTX-U), and plasma-driven synthesis of nanomaterials.

Research Areas
Inorganic Chemistry
Spectroscopy / Physical Chemistry

Honorary Professorship, 111 Program, Tongji University, Shanghai, P. R. China (2013-2017)

EaStCHEM International Visiting Fellowship lecturer, U. of Edinburgh & U. of St. Andrews, Scotland (2008)

George A. Olah Award in Hydrocarbon or Petroleum Chemistry, American Chemical Society (ACS, 2007)

Fellow of the American Association for the Advancement of Science (AAAS, 2004)

Professeur Invité, University de Paris-Sud, Orsay, France (2001)

AIST Guest Researcher Awards, Osaka National Research Institute, Osaka, Japan (1999 and 2000)

Keynote Address, Brazilian Vacuum Society Annual Conf., Sao Jose dos Campos, Brazil (2000)

Fellow of the American Vacuum Society (AVS, 1999)

Distinguished Alumnus of Emporia State University (1998)

Fellow of the American Physical Society (APS, 1996)

Selected Recent Publications

Zhao, P.; Kronawitter, C. X.; Yang, X.; Fu, J.; Koel, B. E., "WO3-alpha-Fe2O3 composite photoelectrodes with low onset potential for solar water oxidation." Physical Chemistry Chemical Physics 2014, 16 (4), 1327-1332.

Gao, J.; Zhao, H.; Yang, X.; Koel, B. E.; Podkolzin, S. G., "Geometric Requirements for Hydrocarbon Catalytic Sites on Platinum Surfaces." Angewandte Chemie International Edition 2014, 53 (14), 3641-3644.

Mativetsky, J. M.; Tarver, J.; Yang, X.; Koel, B. E.; Loo, Y.-L., "Structural origin of anisotropic transport in electrically conducting dichloroacetic acid-treated polymers." Organic Electronics 2014, 15 (2), 631-638.

Xiang, A.; Zhou, S.; Koel, B. E.; Jaffe, P. R., "Transport of poly(acrylic acid) coated 2-line ferrihydrite nanoparticles in saturated aquifer sediments for environmental remediation." Journal of Nanoparticle Research 2014, 16 (4), 1-10.

Kronawitter, C. X.; Zegkinoglou, I.; Shen, S. H.; Liao, P.; Cho, I. S.; Zandi, O.; Liu, Y. S.; Lashgari, K.; Westin, G.; Guo, J. H.; Himpsel, F. J.; Carter, E. A.; Zheng, X. L.; Hamann, T. W.; Koel, B. E.; Mao, S. S.; Vayssieres, L., "Titanium incorporation into hematite photoelectrodes: theoretical considerations and experimental observations." Energy & Environmental Science 2014.

Matsumoto T Fau - Ho, C. S.; Ho Cs Fau - Batzill, M.; Batzill M Fau - Roszell, J. P.; Roszell Jp Fau - Koel, B. E.; Koel, B. E., Ge overlayer and surface alloy structures on Pt(100) studied using alkali ion scattering spectroscopy, x-ray photoelectron spectroscopy and x-ray photoelectron diffraction. J Phys Condens Matter 2014, 26 (13), 1361.

Gao, J.; Zhao, H.; Yang, X.; Koel, B. E.; Podkolzin, S. G., "Controlling Acetylene Adsorption and Reactions on Pt-Sn Catalytic Surfaces." Acs Catalysis 2013, 3 (6), 1149-1153.

He, Q.; Shyam, B.; Nishijima, M.; Yang, X.; Koel, B.; Ernst, F.; Ramaker, D.; Mukerjee, S., "Highly Stable Pt-Au@Ru/C Catalyst Nanoparticles for Methanol Electro-oxidation." Journal of Physical Chemistry C 2013, 117 (3), 1457-1467.

Ho, C.-S.; Martono, E.; Banerjee, S.; Roszell, J.; Vohs, J.; Koel, B. E., "Alloy Formation and Chernisorption at Zn/Pt(111) Bimetallic Surfaces Using Alkali ISS, XPD, and TPD." Journal of Physical Chemistry A 2013, 117 (46), 11684-11694.

Skinner, C. H.; Sullenberger, R.; Koel, B. E.; Jaworski, M. A.; Kugel, H. W., "Plasma facing surface composition during NSTX Li experiments." Journal of Nuclear Materials 2013, 438, S647-S650.

Xiang, A.; Yan, W.; Koel, B. E.; Jaffe, P. R., "Poly(acrylic acid) coating induced 2-line ferrihydrite nanoparticle transport in saturated porous media." Journal of Nanoparticle Research 2013, 15 (7).

Yan, W.; Lien, H.-L.; Koel, B. E.; Zhang, W.-x., "Iron nanoparticles for environmental clean-up: recent developments and future outlook." Environmental Science-Processes & Impacts 2013, 15 (1), 63-77.

Podkolzin, S. G.; Fitzgerald, G. B.; Koel, B. E., "Combining Vibrational Spectroscopies with Quantum Chemical Calculations for Molecular-Level Understanding of Reaction Mechanisms on Catalytic Surfaces." In Applications of Molecular Modeling to Challenges in Clean Energy, Fitzgerald, G.; Govind, N., Eds. 2013; Vol. 1133, pp 153-176.

He, Q.; Yang, X.; He, R.; Bueno-Lopez, A.; Miller, H.; Ren, X.; Yang, W.; Koel, B. E., "Electrochemical and spectroscopic study of novel Cu and Fe-based catalysts for oxygen reduction in alkaline media." Journal of Power Sources 2012, 213, 169-179.

Yang, X.; Kimmel, Y. C.; Fu, J.; Koel, B. E.; Chen, J. G., "Activation of Tungsten Carbide Catalysts by Use of an Oxygen Plasma Pretreatment." Acs Catalysis 2012, 2 (5), 765-769.

Yang, X.; Koel, B. E.; Wang, H.; Chen, W.; Bartynski, R. A., Nanofaceted C/Re(112̅1): "Fabrication, Structure, and Template for Synthesizing Nanostructured Model Pt Electrocatalyst for Hydrogen Evolution Reaction." ACS Nano 2012, 6 (2), 1404-1409.

Yan, W.; Ramos, M. A. V.; Koel, B. E.; Zhang, W.-x., As(III) "Sequestration by Iron Nanoparticles: Study of Solid-Phase Redox Transformations with X-ray Photoelectron Spectroscopy." The Journal of Physical Chemistry C 2012, 116 (9), 5303-5311.

Yan, W.; Vasic, R.; Frenkel, A. I.; Koel, B. E., "Intraparticle Reduction of Arsenite (As(III)) by Nanoscale Zerovalent Iron (nZVI) Investigated with In Situ X-ray Absorption Spectroscopy." Environmental Science & Technology 2012, 46 (13), 7018-7026.

He, Q.; Yang, X.; Ren, X.; Koel, B. E.; Ramaswamy, N.; Mukerjee, S.; Kostecki, R., "A novel CuFe-based catalyst for the oxygen reduction reaction in alkaline media." Journal of Power Sources 2011, 196 (18), 7404-7410.

Yang, X.; Hu, J.; Fu, J.; Wu, R.; Koel, B. E., "Role of Surface Iron in Enhanced Activity for the Oxygen Reduction Reaction on a Pd3Fe(111) Single-Crystal Alloy." Angewandte Chemie-International Edition 2011, 50 (43), 10182-10185.

Kim, J.; Fu, J.; Podkolzin, S. G.; Koel, B. E., "Studies of Ethylene Oxide Adsorption on Pt-Sn Alloys with TPD, HREELS, UPS, and DFT Calculations." Journal of Physical Chemistry C 2010, 114 (40), 17238-17247.

Koel, B., Structure, "Characterization and Reactivity of Pt–Sn Surface Alloys." In Model Systems in Catalysis, Rioux, R., Ed. Springer New York: 2010; pp 29-50.

Lahiri, J.; Mayernick, A.; Morrow, S. L.; Koel, B. E.; van Duin, A. C. T.; Janik, M. J.; Batzill, M., "Modification of Active Sites on YSZ(111) by Yttria Segregation." Journal of Physical Chemistry C 2010, 114 (13), 5990-5996.

Yan, W.; Ramos, M. A. V.; Koel, B. E.; Zhang, W.-x., "Multi-tiered distributions of arsenic in iron nanoparticles: Observation of dual redox functionality enabled by a core-shell structure." Chemical Communications 2010, 46 (37), 6995-6997.

Yang, X.; Hu, J.; Wu, R.; Koel, B. E., "Formation of Pd Monomers and Dimers on a Single-Crystal Pd3Fe(111) Surface." Journal of Physical Chemistry Letters 2010, 1 (16), 2493-2497.