All entries for harry tuller

Harry L. Tuller

Department: Department of Materials Science and Engineering
Title: Professor

Collaborators

K. Shah, RMD, MA
I. D. Kim, KAIST, Korea
D. Nocera, MIT, Harvard
R. Moos, Univ. Bayreuth Germany
B. Yildiz, MIT
K. Van Vliet, MIT
J. Varela, UNESP, Brazil
M. Orlandi, UNESP, Brazil
A. Gougam, Abu Dhabi
T. Buonassisi, MIT

Graduate Students

M. Campion, Res. Asst., MSE
D. Chen, Res. Asst., MSE
J. Engel, Res. Asst., MSE
J.J. Kim, Res. Asst., MSE
N. Thompson, Res. Asst., MSE
A. Felix, visiting student, MSE
G. Whitfield, Res. Asst., MSE

PostDoctoral Associate

M. Kuhn, MSE

Visiting Scientist

S. Bishop, MSE
J. Rupp, MSE, NSE
M. Orlandi, MSE
N. Perry, MSE
D. Marocchelli, MSE

Support Staff

E. Anderson, Administrative Assistant II

Publications

D. Chen, S.R. Bishop, and H.L. Tuller, Praseodymium-cerium oxide thin film cathodes: Study of Oxygen Reduction Reaction Kinetics, J. Electroceramics, 28, 62–69 (2012).

H.L. Tuller. S.R. Bishop, D. Chen, Y. Kuru; J.-J. Kim; T.S. Stefanik, Praseodymium Doped Ceria: Model Mixed Ionic Electronic Conductor With Coupled Electrical, Optical, Mechanical and Chemical Properties, Solid State Ionics. 225, 194-197 (2012).

W. Jung and H. L. Tuller, Investigation of Surface Sr Segregation in Model Thin Film Solid Oxide Fuel Cell Perovskite Electrodes, Energy Environ. Sci., 5, 5370-5378 (2012).

D. Marrocchelli, S. R. Bishop, H. L. Tuller and B. Yildiz, Understanding Chemical Expansion in Non-stoichiometric Oxides: Ceria and Zirconia Case Studies, Advanced Functional Materials, 22 [9] 1958-1965 (2012).

S. R. Bishop, J. J. Kim, N. Thompson, and H. L. Tuller, Probing Redox Kinetics in Pr Doped Ceria Mixed Ionic Electronic Conducting Thin Films by In Situ Optical Absorption Measurements, ECS Transactions, 45 (1), 491-495 (2012), in Ionic and Mixed Conducting Ceramics 8, Editor(s): M. Mogensen, T. Armstrong, T. Gur, H. Yokokawa, X. Zhou.

S. R. Bishop, D. Marrocchelli, Y. Kuru, H. L. Tuller, and B. Yildiz, Development of a Predictive Thermo-Chemical Expansion and Stress Model in (Pr,Ce)O_2-δ, ECS Trans. 41(33), 153-159 (2012), in Electrochemical Synthesis of Fuels 1, Editor(s): X. Zhou, M. Mogensen, G. Brisard, J. Fenton, W. Mustain,

S. R. Bishop, T. S. Stefanik, and H. L. Tuller, Defects and Transport in Pr_xCe_1-xO_2-δ: Composition Trends, J. Mat. Res. 27 [15], 2009-2016 (2012) (Focus Issue on Advanced Materials For Fuel Cells)

J.-J. Kim; S. R. Bishop; N. Thompson; Y. Kuru; H. L. Tuller, Optically Derived Energy Band Gap States of Pr in Ceria, Solid State Ionics. 225, 198-200 (2012).

Y. Chen, W. Jung, Z. Cai,J. J. Kim, H. L. Tuller and B. Yildiz, Impact of Sr Segregation on the Electronic Structure and Oxygen Reduction Activity of SrTi_1-xFe_xO₃Surfaces, Energy and Environ. Sci. 5, 7979-7988 (2012).

A. Geupel, S. R Bishop, D. J. Yang, H. L Tuller, and R. Moos, The Electrical Properties of NOx-storing Carbonates During NOx Exposure, Solid State Ionics. 225, 317-323 (2012).

H.L. Tuller, Materials for High Temperature Electrochemical Applications: Automotive Sensors, Catalysts and Traps, in Proceedings IMCS 2012 – The 14th International Meeting on Chemical Sensors, Nuremberg, Germany, Editor R. Moos. Publ. AMA Service GmbH, Wunstorf, Germany, 2012, p.56-59.

A. Groß, T. Weller, H.L. Tuller, R. Moos, Study of the Electrical Conductivities of the NOx Trap Materials BaCO₃ and K₂CO₃/La-Al₂O₃ During NOx Exposure as Sensitive Layers for In-situ Characterization of Catalyst Systems, in Proceedings IMCS 2012 – The 14th International Meeting on Chemical Sensors, Nuremberg, Germany, Editor R. Moos. Publ. AMA Service GmbH, Wunstorf, Germany, 2012, p. 1664-1667.

S. R. Bishop, H. L. Tuller, J. Engel, W. Higgins, G. Ciampi, A. Churilov, and K. S. Shah, The Defect and Transport Properties of Acceptor Doped TlBr: Role of Dopant Exsolution and Association, Phys. Chem. Chem. Phys., 14, 10160-10167 (2012).

D. Marrocchelli, S. R. Bishop, H. L. Tuller, G. W. Watson and B. Yildiz,_,The Effect of Charge Localization on Chemical Expansion in Cerium Oxide, Phys. Chem. Chem. Phys., 14, 12070-12074 (2012). (Article selected for cover).

D. J. Yang, G. C. Whitfield, N. G. Cho, P.-S. Cho, I.-D. Kim, H. Saltsburg and H. L. Tuller, Amorphous InGaZnO₄ Films: Gas Sensor Response and Stability, Sensors & Actuators B, 171-172, 1166-1171 (2012).

S. R. Bishop, G. Ciampi, C. D. Lee, M. Kuhn, H. L. Tuller, W. Higgins, and K. S. Shah, Ionic Conductivity of TlBr_1-xI_x (x = 0, 0.2, 1): Candidate Gamma Ray Detector, IEEE Trans. Nucl. Sci., 59 [5, pt 3], 2424-2427 (2012).

S. R. Bishop and H. L. Tuller, Impact of Donor Dopant on Acceptor Solubility in TlBr, ECS Transactions – Honolulu, Hawaii Volume 50, MEMS/NEMS 10, Honolulu, HI meeting. Accepted for publication 7/23/12.

H. G. Moon, Y.-S. Shim, D. H. Kim, H. Y. Jeong, M. Jeong, J. Y. Jung, S. M. Han,J.-K. Kim, J.-S. Kim, H.-H. Park, J.-H. Lee, H. W. Jang, S.-J. Yoon, H. L. Tuller, Self-activated ultrahigh chemosensitivity of oxide thin film nanostructures for transparent sensors, Scientific Reports, 2, 588 (2012) 7 pages,

R. Korobko, A. Patlolla, A. Kossoy, E. Wachtel, H. L. Tuller, A. I. Frenkel, I. Lubomirsky,Giant Electrostriction in Gd-Doped Ceria, Adv. Mater., 24, 5857-5861 (2012) – DOI: 10.1002/adma.201202270.

H.L. Tuller, Materials for High Temperature Electrochemical Applications: Automotive Sensors, Catalysts and Traps, Sensors & Actuators B, 2012.

F. Gao, D. Chen, B. Lu, H. L. Tuller, C. V. Thompson, S. Keller, U. K. Mishra, and T. Palacios, Impact of Moisture and Fluorocarbon Passivation on the Current Collapse of AlGaN/GaN HEMTs, IEEE Electron Device Letters, 33 [10], 1378 – 1380 (2012).

Y. Kuru, D. Marrocchelli, S.R. Bishop, D. Chen, B. Yildiz and H.L. Tuller, Anamalous Chemical Expansion Behavior of Pr_0.2Ce_0.8O_2- Thin Films Grown by Pulsed Laser Deposition, J. Electrochem. Soc. 159 [11], F799-F803 (2012).

J. Shin , S.-J. Choi , I. Lee , D.-Y. Youn , C. O. Park ,J.-H. Lee , H. L. Tuller , and I.-D. Kim, Thin-Wall Assembled SnO₂ Fibers Functionalized by Catalytic Pt Nanoparticles and their Superior Exhaled-Breath-Sensing Properties for the Diagnosis of Diabetes, Adv. Funct. Mater. 2012.

D. Chen, S. R. Bishop, and H. L. Tuller, Non-stoichiometry in Oxide Thin Films: A Chemical Capacitance Study of the Praseodymium-Cerium Oxide System, Adv. Funct. Mater. 2012.

Catalytic Oxygen Storage Materials

Authors: D. Chen, S. R. Bishop, M. Kuhn, H. L. Tuller (in collaboration with R. Moos, University of Bayreuth, Germany)
Sponsorship: NSF - Materials World Network

Combustion of fossil fuels, essential for electricity generation and vehicular propulsion, is generally incomplete, leading to harmful NOx, CO, and unburned hydrocarbon emissions. Progress in minimizing such emissions has relied on the operation of “three-way catalysts” (TWCs), which utilize a combination of precious metals and metal oxides with the ability to take up or release oxygen for reduction/oxidation of pollutants (NOx to N₂ and CO & HC to CO₂ & H₂O, respectively). In this project, we investigate the rate at which oxygen storage materials (OSM, typically Ce_xZr_1-xO_2-δ) exchange oxygen with the atmosphere and the magnitude of oxygen that they store with the aid of geometrically well-defined thin film structures. Impedance spectroscopy; Kelvin probe; and thermogravimetry, Raman scattering, and electrical conductivity measurement methods are used to determine electrochemical performance and oxygen storage capabilities. These properties, when correlated to actual TWC performance using a differential flow reactor, will allow for a more detailed understanding of performance criteria. Previous studies on Pr_xCe_1-xO₂ in our group have demonstrated the feasibility of these approaches^[1]^[2]^[3]^[4]^[5].

P. Forzatti, L. Castoldi, I. Nova, L. Lietti, and E. Tronconi, “NOx removal catalysis under lean conditions,” Catalysis Today, vol. 117, no. 1–3, pp. 316–320, Sep. 2006. [↩]
M. Kuhn, S. R. Bishop, H. L. Tuller, and J. L. M. Rupp, “Structural characterization and oxygen nonstoichiometry of ceria-zirconia Ce_1-xZr_xO_2-δ solid solutions,” Acta Materialia vol. 61, pp. 4277-4288 2013. [↩]
D. Chen, S. R. Bishop, and H. L. Tuller, “Praseodymium-cerium oxide thin film cathodes: Study of oxygen reduction reaction kinetics,” Journal of Electroceramics, vol. 28, no. 1, pp. 62–69, 2012. [↩]
D. Chen, S. Bishop, and H. L. Tuller, “The chemical capacitance of praseodymium-cerium oxide thin films and relationship to nonstoichiometry,” Advanced Functional Materials, online, 2012. [↩]
S. R. Bishop, T. S. Stefanik, and H. L. Tuller, “Electrical conductivity and defect equilibria of Pr_0.1Ce_0.9O_2-δ,” Physical Chemistry Chemical Physics : vol. 13, no. 21, pp. 10165–73, June 2011 [↩]

Utilization of Doped-ZnO and Related Materials Systems for Transparent Conducting Electrodes

Authors: M. Campion, H. L. Tuller (in collaboration with A. Gougam, T. Buonassisi)
Sponsorship: Masdar Institute of Science and Technology

Efficient transparent electrode materials are vital for applications in smart window, LED display, and solar cell technologies. These materials must possess a wide band gap for minimal optical absorption in the visible spectrum while maintaining a high electrical conductivity. Currently, tin-doped indium oxide (ITO) is the industry standard for transparent electrodes, but limitations in both deposition temperature and use of the rare element indium has led to a search for better material alternatives. Doped ZnO represents one of the most promising alternatives, but the mechanisms by which processing conditions and defect chemistry affect the final material properties are not well understood. Reported values of the electrical conductivity for doped ZnO span orders of magnitude for seemingly similar processing conditions performed by different experimental groups. This work seeks to better understand the relationships between processing, defect chemistry, and material properties through in situ and ex situ optical and electrical investigation of doped ZnO, deposited by pulsed laser deposition and magnetron sputtering methods.

Direct Solar to Hydrogen Conversion: Low Cost Photoelectrodes

Authors: J. Engel, H. L. Tuller (in collaboration with D. G. Nocera)
Sponsorship: MIT Energy Initiative

With continuously growing energy demands, alternative emission-free solar-energy solutions become ever more attractive. However, to achieve sustainability, efficient conversion and storage of solar energy is imperative^[1],^[2]. Photoelectrolysis harnesses solar energy to evolve hydrogen and oxygen from water, thereby enabling energy storage via chemical means. This work investigates photoelectrodes that offer high conversion efficiency, long-term stability, and low cost. The focus is initially on semiconducting metal oxides in which the energy bands, the defect chemistry, and microstructures are tuned to optimize optical absorption, charge transport, and to reduce overpotentials. For high efficiency, transition metal-based oxidation catalysts^[3] are implemented at the photoelectrode. The electro-deposition kinetics of these catalysts are also investigated to allow further insights into the catalytic mechanisms.

N. S. Lewis and D. G. Nocera, “Powering the planet: Chemical challenges in solar energy utilization,” Proc. Natl. Acad. Sci. U.S.A. vol. 103, pp. 15729-15735, 2006. [↩]
R. van de Krol, Y. Liang, and J. Schoonman, “Solar hydrogen production with nanostructured metal oxides,” J. Mater. Chem. vol. 18, pp. 2311-2320, 2008. [↩]
M. W. Kanan and D. G. Nocera, “In situ formation of an oxygen-evolving catalyst in neutral water containing phosphate and Co²⁺,” Science vol. 321, pp. 1072-1075, 2008. [↩]

Chemomechanics of Fuel-cell-related Materials

Authors: S. R. Bishop, J. J. Kim, H. L. Tuller (in collaboration with B. Yildiz, K. V. VlietS. Yip)
Sponsorship: Department of Energy

Solid oxide fuel cells (SOFCs) convert chemical energy directly into electrical energy with higher efficiency and lower emission than conventional energy systems, and SOFCs provide flexibility of fuel choice allowing to use a wide variety of fuels ranging from hydrogen and kerosene to gasified coal^[1],^[2]. During operation, many of the advanced oxides utilized in SOFCs experience significant changes in oxygen content, or oxygen nonstoichiometry, resulting in changes in volume and elastic properties termed chemomechanics^[3],^[4]. This lattice dilation known as chemical expansion is oxygen nonstoichiometry-induced, and large stress gradients can be developed across a SOFC stack with potential for negative impact on device performance^[5]. Therefore, a fundamental understanding regarding the coupling between solid-state electrochemistry and mechanical deformation is required for successful development of functionally superior and long-lived fuel cell systems. In this project, we are studying the chemical expansion coefficient, elastic properties, and oxygen nonstoichiometry of thin film and bulk SOFC oxide materials. Thin films are of particular interest because they allow control of strain and increase the surface-to-volume ratio, which is particularly important for electrode performance. Furthermore, there is a trend towards the use of thinner structures such as µ-SOFCs^[6]. The chemomechanical properties are being investigated using high-temperature and atmosphere-controlled nanoindentation, high-temperature x-ray diffraction, dilatometry, impedance spectroscopy, optical transmittance spectroscopy, and thermo-gravimetry techniques.

B. C. H. Steele and A. Heinzel, “Materials for fuel-cell technologies,” Nature, vol. 414, pp. 345-352, Nov 2001. [↩]
M. Mogensen and K. Kammer, “Conversion of hydrocarbons in solid oxide fuel cells,” Ann. Rev. Mater. Res., vol. 33, pp. 321-331, Aug 2003. [↩]
H. L. Tuller and S. R. Bishop, “Point defects in oxides: tailoring materials through defect engineering,” Ann. Rev. Mater. Res., vol. 41, pp. 369-398, Aug 2011. [↩]
Y. Kuru, S. R. Bishop, J. J. Kim, B. Yildiz, and H. L. Tuller, “Chemomechanical properties and microstructural stability of nanocrystalline Pr-doped ceria: An in situ X-ray diffraction investigation,” Solid State Ionics, vol. 193, pp.1-4, June 2011. [↩]
K. Sato, H. Omura, T. Hashida, K. Yashiro, H. Yugami, T. Kawada, and J. Mizusaki, “Tracking the onset of damage mechanism in ceria-based solid oxide fuel cells under simulated operating conditions,” Journal of Testing and Evaluation, vol. 34, pp. 246-250, May 2006. [↩]
A. Evans, A. Bieberle-Hütter, J. L. M. Rupp, and L. J. Gauckler, “Review on microfabricated micro-solid oxide fuel cell membranes,” Journal of Power Sources, vol. 194, pp. 119-129, Oct 2009. [↩]

Investigation of Fuel Cell Cathode Performance in Solid Oxide Fuel Cells – Application of Model Thin Film Structures

Authors: J. J. Kim, D. Chen, N. Thompson, N. Perry, S. R. Bishop. H. L. Tuller
Sponsorship: Department of Energy

Understanding the oxygen reduction reaction (ORR) kinetics at solid oxide fuel cell (SOFC) cathodes is considered critical for enhanced performance, especially at reduced operating temperatures. Although numerous research efforts have been directed toward understanding the electrode reaction mechanisms, they remain unsatisfactory, and their conclusions are controversial^[1],^[2]. The complete ORR at mixed conducting cathode thin films consists of oxygen adsorption, dissociation, charge-transfer, and incorporation steps. The kinetic parameters associated with the overall reaction such as the diffusion coefficient (D) and surface exchange coefficient (k) are strongly influenced by oxygen nonstoichiometry, ∂. Because many advanced oxides used in SOFC experience significant changes in ∂ during operation at elevated temperatures and under reducing/oxidizing conditions, the ability to diagnose a material’s behavior under operating conditions is important. Our group recently demonstrated that d in Pr_0.1Ce_0.9O_2-∂ (10 PCO) thin films was reliably derived by utilizing chemical capacitance extracted from electrochemical impedance spectroscopy (EIS) measurements^[3]. Furthermore, we introduced a non-contact optical means for in situ recording of transient redox kinetics as well as the equilibrium Pr oxidation state and, in turn, ∂ in 10 PCO thin films, by monitoring the change in absorption spectra upon change in pO₂ or temperature^[4],^[5]. In this project, we are investigating cathode kinetics and nonstoichiometry of two model cathode oxide thin film; Ba_xSr_1-xTi_1-yFe_yO_3-y/2+δ (BSTF) and Pr_xCe_1-xO_2-∂ (PCO) by utilizing impedance spectroscopy and in situ optical absorption spectroscopy as a function of temperature and pO₂. Changes in surface chemistry and their impact on electrode impedance are also being investigated by using atomic force microscopy, x-ray photoelectron spectroscopy and low-energy ion scattering spectroscopy.

S. B. Alder, “Factors governing oxygen reduction in solid oxide fuel cell cathodes,” Chem. Rev., vol. 104, pp. 4791-4843, Oct. 2004. [↩]
W. Jung and H. L. Tuller, “A new model describing solid oxide fuel cell cathode kinetics: model thin film SrTi_1-xFe_xO₃_-d mixed conducting oxide – a case study,” Adv. Energy Mater., vol. 1, pp. 1184-1191, Nov. 2011. [↩]
D. Chen, S. R. Bishop and H. L. Tuller, “Non-stoichiometry in oxide thin films: a chemical capacitance study of the praseodymium-cerium oxide system,” Adv. Funct. Mater., DOI: 10.1002/adfm.201202104 [↩]
J. J. Kim, S. R. Bishop, N. Thompson, Y. Kuru and H. L. Tuller, “Optically derived energy band gap states of Pr in ceria,” Solid State Ionics, vol. 225, pp. 198-200, Oct. 2012. [↩]
S. R. Bishop, J. J. Kim, N. Thompson and H. L. Tuller, “Probing redox kinetics in Pr doped ceria mixed ionic electronic conducting thin films by in situ optical absorption measurements”, ECS transactions, vol. 45, pp. 491-495, 2012. [↩]

Ionic Conduction Studies in TlBr Radiation Detector Materials

Authors: S. R. Bishop, M. Kuhn, H. L. Tuller (in collaboration with K. Shah)
Sponsorship: Domestic Nuclear Detection Office, Radiation Monitoring Devices, Inc.

Detection of high-energy radiation (e.g., γ-rays) is key in nuclear non-proliferation strategies. When a wide-band gap semiconductor detector intercepts a γ-ray, electron-hole pairs are formed, resulting in an increase in electrical conductivity. This change in conductivity is maximized if the conductivity in the non-illuminated (dark) state is very low. Current semiconductor technologies require cooling to very low temperatures, adding to cost and reducing portability. TlBr is an attractive detector material given its low room temperature dark conductivity, as well as its high mass density, leading to higher radiation absorption.

In this project, we characterize the dominant ionic conduction properties in TlBr, dopant association, and exsolution using impedance spectroscopy. Through doping techniques, we have determined that TlBr is primarily a Schottky- type ionic conductor, meaning that Tl and Br move through the material by vacancy motion. These measurements have led us to predict a doping strategy to minimize the dark conductivity. We are collaborating with a local company (Radiation Monitoring Devices, Inc.) to implement this technology as well as developing it further by studying new TlBr-based material systems. The focus has now shifted to understanding long-term aging affects tied to electrode processes.

MTL Annual Research Report 2013