Analy­sis of the Mech­a­nism of Elec­tro­chem­i­cal Oxy­gen Reduc­tion and Devel­op­ment of Ag– and Pt-alloy Cat­a­lysts for Low Tem­per­a­ture Fuel Cells

2014 Spring Symposium

 
Suljo Linic

 
Abstract – The oxygen reduction reaction (ORR) is the major source of overpotential loss in low-temperature fuel cells. Expensive, Pt-based materials have been found to be the most effective catalysts, but exploration of alternatives has been hampered by stability constraints at the typical operating conditions of low pH and high potential.

I will discuss how we studied elementary mechanism of ORR on various metal electrodes using kinetic and micro-kinetic analysis of reaction pathways and quantum chemical calculations. These studies allowed us to identify the elementary steps and molecular descriptors that govern the rate of ORR. Using these performance descriptors we have been able to identify families of Pt and Ag-based alloys that exhibit superior ORR performance is acid and base respectively.

We have synthesized these alloys to demonstrate the superior ORR activity with rotating disk electrode experiments. We have also performed thorough structural characterization of the bulk and surface properties with a combination of cyclic voltammetry, x-ray diffraction, and electron microscopy with spatially resolved energy-dispersive x-ray spectroscopy and electron energy loss spectroscopy.
 

Reference

  1. Holewinski and Linic. J. Electrochem. Soc. 159, (2012).

 
Suljo_LinicBiography – Prof. Linic obtained his PhD degree, specializing in surface and colloidal chemistry and heterogeneous catalysis, at the University of Delaware in 2003 under the supervision of Prof. Mark Barteau after receiving his BS degree in Physics with minors in Mathematics and Chemistry from West Chester University in West Chester (PA). He was a Max Planck postdoctoral fellow with Prof. Dr. Matthias Scheffler at the Fritz Haber Institute of Max Planck Society in Berlin (Germany), working on first principles studies of surface chemistry. He started his independent faculty career in 2004 at the Department of Chemical Engineering at the University of Michigan in Ann Arbor where he is currently the Class of 1983 Faculty Scholar Professor of chemical engineering.

Prof. Linic’s research has been recognized through multiple awards including the 2014 ACS (American Chemical Society) Catalysis Lectureship for the Advancement of Catalytic Science, awarded annually by the ACS Catalysis journal and Catalysis Science and Technology Division of ACS, the 2011 Nanoscale Science and Engineering Forum Young Investigator Award, awarded by American Institute of Chemical Engineers, the 2009 ACS Unilever Award awarded by the Colloids and Surface Science Division of ACS, the 2009 Camille Dreyfus Teacher-Scholar Award awarded by the Dreyfus Foundation, the 2008 DuPont Young Professor Award, and a 2006 NSF Career Award. Prof. Linic has presented more than 100 invited and keynote lectures and published more than 50 peer reviewed articles in leading journals in the fields of general science, Physics, Chemistry, and Chemical Engineering.

Wel­come to HEL – Bet­ter Chem­istry – Faster

2014 Spring Symposium

 


 
HEL is a leading equipment provider for catalytic processes in chemical, petrochemical and pharmaceutical Industry. Stirred and fixed-bed reactors for catalytic & thermal conversions (hydrogenation reactor, polymerization, hydrocracking, bio-fuel synthesis etc.) are supplied to a range of industries. Often at elevated temperature & pressure, HEL specializes in research scale, multi-reactor and high pressure reactors processing, testing, equipment and systems. Custom designs to client flow sheets are also supplied including pilot scale processes.

Life Cycle of Cat­alytic Diesel Emis­sion Con­trol Sys­tems

2014 Spring Symposium

 
Aleksey Yezerets, Neal Currier, Krishna Kamasamudram, Junhui Li, Hongmei An, Ashok Kumar, Jinyong Luo, Saurabh Joshi


 
Abstract – A diverse spectrum of highly capable diesel catalytic emission control systems has emerged in the recent years, in response to stringent environmental regulations in several leading world markets. By taking the brunt of the emission reduction, these highly effective systems allowed the engines to be designed and tuned for maximum fuel efficiency and minimum CO2 emissions.

Unlike their gasoline emission control predecessors, diesel systems include multiple catalysts with distinct functions, along with a variety of sensors and actuators, thus representing veritable chemical plants. For example, the emission control system commercialized in Cummins-powered 2010 heavy-duty diesel vehicles includes four distinct catalytic devices, a diesel oxidation catalyst (DOC), catalyzed diesel particulate filter (DPF), selective catalytic reduction (SCR) catalyst, and an ammonia slip selective oxidation catalyst (ASC). The system further includes eight sensors, and two fluid injectors, along with the respective controls and diagnostic algorithms. Another system, commercialized by Cummins in 2007 and 2010 Dodge Ram pickups, is based on a NOx adsorber catalyst and represents similar level of sophistication. Underlying the system-level complexity is the intricacy of the individual catalytic elements, some of which include multiple distinct chemical functions and complex topology.

Predictably, lifecycles of such systems are shaped by the behaviors of the individual catalytic elements and their interactions. These often feature a variety of reversible processes, in response to deposition and removal of various poisons and masking agents, reversible chemical and morphological changes, along with irreversible degradation, often referred to as aging.

In this presentation, we will review several examples of interactions between catalysts in the context of the above diesel emission control systems, emphasizing how the recent advances in their practical application were underpinned by the developments in the broader field of heterogeneous catalysis and reaction engineering.
 
Aleksey_YezeretsBiography – At Cummins, the world’s largest independent manufacturer of diesel engines and related equipment, Dr. Yezerets leads an R&D team responsible for guidance and support of emission control products at all stages of their lifecycle, and coordinates a portfolio of collaborative research programs with National Labs, universities and industrial partners. Dr. Yezerets serves on the Editorial Board of the Journal of Applied Catalysis B: Environmental, has acted as a guest editor of three issues of the Catalysis Today Journal, and organized a number of environmental catalysis sessions in industrial and academic meetings. He has received 11 US patents, published over 50 peer-reviewed articles, as well as presented numerous invited, keynote, and award lectures. Dr. Yezerets has a special appointment to the Graduate Faculty of Chemical Engineering at Purdue University. His contributions to the field of catalytic emission control were recognized by the Herman Pines Award in Catalysis, R&D 100 Award, national awards by the American Chemical Society, American Institute of Chemical Engineers, and Society Automotive Engineering, as well as Julius Perr Award for Innovation by Cummins.

Renewable production of phthalic anhydride from biomass-derived furan and maleic anhydride

Meeting Program – January 2014

 
Eyas Mahmoud†, Donald A. Watson‡ and Raul F. Lobo†
†Catalysis Center for Energy Innovation
Department of Chemical and Biomolecular Engineering
University of Delaware
Newark, DE 19716 USA
 
‡Department of Chemistry and Biochemistry
University of Delaware
Newark, DE 19716 USA

 
Abstract – A route to renewable phthalic anhydride (2-benzofuran-1,3-dione) from biomass-derived furan and maleic anhydride (furan-2,5-dione) is investigated. Furan and maleic anhydride were converted to phthalic anhydride in two reaction steps: Diels Alder cycloaddition followed by dehydration. Excellent yields for the Diels-Alder reaction between furan and maleic-anhydride were obtained at room temperature and solvent-free conditions (SFC) yielding 96% exo-4,10-Dioxa-tricyclo[5.2.1.0]dec-8-ene-3,5-dione (oxanorbornene dicarboxylic anhydride) after 4 hrs of reaction. It is shown that this reaction is resistant to thermal runaway because its reversibility and exothermicity. The dehydration of the oxanorbornene was investigated using mixed-sulfonic carboxylic anhydrides in methanesulfonic acid (MSA). An 80% selectivity to phthalic anhydride (87% selectivity to phthalic anhydride and phthalic acid) was obtained after running the reaction for 2 hrs at 298 K to form a stable intermediate followed by 4 hrs at 353 K to drive the reaction to completion. The structure of the intermediate was determined. This result is much better than the 11% selectivity obtained in neat MSA using similar reaction conditions.
 
Biography – Eyas Mahmoud, recipient of the AIChE SCI Scholar award, graduated summa cum laude from from the University of Pennsylvania with a B.S.E.in Chemical and Biomolecular Engineering in 2011. Since then he received the NSF Graduate Research Fellowship (GRFP) and went on to pursue a Ph.D. in the Department of Chemical and Biomolecular Engineering from the University of Delaware, under the supervision of Professor Raul F. Lobo. His thesis work focuses on the renewable production of aromatics from biomass-feedstocks. Recently, he has published work on the renewable production of phthalic anhydride from furan and maleic anhydride by using mixed sulfonic-carboxylic anhydrides.

Thermodynamics and kinetics of elementary reaction steps on late transition metal catalysts, and using them to search for better catalysts

Meeting Program – November 2013

 
Charles T. Campbell
Departments of Chemistry and of Chemical Engineering
University of Washington
Seattle, WA 98195-1700

 
Abstract – A survey of experimental and theoretical results concerning the thermodynamics and kinetics of surface chemical reactions of importance in late transition metal catalysis for energy technology will be presented. Topics include: (1) calorimetric measurements of the adsorption energies of small molecules and molecular fragments on single crystal surfaces, and their comparison to DFT results; (2) new measurements of the entropies of adsorbates and the trends they follow, and (3) new ways to estimate prefactors in the rate constants for elementary steps in surface reactions. We will also discuss how to use these together with DFT calculations and/or elementary-step rate measurements to build microkinetic models for multi-step catalytic reactions. Finally, we will discuss a method for analyzing these to quantify the extent to which each elementary step and intermediate controls the net rate, and describe how one can use this to define the key descriptors that can be used for computational searches to discover better catalyst materials.
 
Charles_Campbell2-1024x853Biography – Charles T. Campbell is the Rabinovitch Endowed Chair in Chemistry at the University of Washington, where he is also Adjunct Professor of Chemical Engineering and of Physics. He is the author of over 270 publications on surface chemistry, catalysis and biosensing. He is an elected Fellow of both the ACS and the AAAS, and Member of the Washington State Academy of Sciences. He received the Arthur W. Adamson Award of the ACS and the ACS Award for Colloid or Surface Chemistry, the Gerhard Ertl Lecture Award, the Robert Burwell Award/Lectureship of the North American Catalysis Society, the Ipatieff Lectureship at Northwestern University and an Alexander von Humboldt Research Award. He served as Chair, Chair-Elect, Vice-Chair and Treasurer of the Colloid and Surface Chemistry Division of the ACS. He served as founding Co-Director and Director of the University of Washington’s Center for NanoTechnology, and as Editor-in-Chief of the journal Surface Science for ten years. He is currently Editor-in-Chief of Surface Science Reports, and serves on the Editorial Boards of the Journal of Physical Chemistry and Catalysis Reviews and the Scientific Advisory Board of Catalysis Letters and Topics in Catalysis. He received his B.S. in Chemical Engineering (1975) and his Ph.D. in Physical Chemistry (1979, under J. M. White) from the University of Texas at Austin, and then did research in Germany under Gerhard Ertl (2007 Nobel Prize Winner) through 1980.

Developing Ceria-Based Catalysts

Meeting Program – October 2013

 
Raymond J. Gorte
Department of Chemical & Biomolecular Engineering
University of Pennsylvania
Philadelphia, PA 19104

 
Abstract – Ceria-supported metal catalysts are widely used in automotive emissions control, where ceria provides “Oxygen Storage Capacitance”. Ceria-supported metals also have potential for a large number of other applications, ranging from methane oxidation to the water-gas-shift reaction, due to the enhanced properties that ceria imparts. However, the activities and stabilities depend strongly on the structure of the ceria and whether or not it is mixed with a second oxide. Catalyst properties are also affected by how catalytic metals interact with the support.

In this talk, I will first discuss work aimed at understanding the role that ceria plays in oxygen storage and demonstrate that the thermodynamic redox properties of catalytic forms of ceria differ from that of bulk ceria. I will then talk about our efforts to maximize the interactions between catalytic metals and ceria, as well as prevent sintering of the metal particles, through the preparation of core-shell catalysts deposited onto a functionalized-alumina support. These core-shell catalysts exhibit exceptional activity for methane oxidation, with impressive stability at high temperatures.
 
ray_gorteBiography – Raymond J. Gorte joined the faculty at the University of Pennsylvania in 1981 after receiving his PhD in Chemical Engineering from the University of Minnesota. He is currently the Russell Pearce and Elizabeth Crimian Heuer Professor of Chemical & Biomolecular Engineering, with a secondary appointment in Materials Science & Engineering. Since joining Penn, Ray has served as Chairman of Chemical Engineering from 1995 to 2000 and was the Carl V. S. Patterson Professor of Chemical Engineering from 1996 through 2001. He received the 1997 Parravano Award of the Michigan Catalysis Society, the 1998 Philadelphia Catalysis Club Award, the 1999 Paul Emmett Award of the North American Catalysis Society, the 2001 Penn Engineering Distinguished Research Award, and the 2009 AIChE Wilhelm Award. He has served as Chairman of the Gordon Conference on Catalysis (1998) and Program Chairman of the 12th International Zeolite Conference (1998). He is an Associate Editor of the Journal of the Electrochemical Society. His present research interests are focused on electrodes for solid-oxide fuel cells and the catalytic properties of core-shell materials. He is also known for his research on zeolite acidity and for metal-support effects, especially with ceria-supported precious metals, used in automotive emissions control.