Research Interests:

Theoretical investigation of chemical reactions in SOFC.
Group leader: Dr. Tom Ziegler
Group members: Tebikie W. Habtu, Swati Vartak, Maxim Shishkin.

In our group we perform theoretical studies of fuel oxidation on the anode and electrolyte surfaces, anode degradation as a result of coking and sulfur poisoning and the mechanisms of enhancement of fuel cell performance. As a tool we utilize quantum mechanical computer calculations that enable to obtain information about the energetically favorable reaction pathways and provide the insights into the electronic structure. To provide a macroscopic link and include temperature and pressure effects we perform kinetic modeling simulations, which require results of quantum mechanical calculations as input parameters.

The main research objectives, addressed in our group are:

1. Investigation of the microscopic mechanisms of coking on the Ni-based anodes of SOFC and suggestions for coke reduction. To this end we formulated the underlying principles of two possible strategies for suppressing coke formation (alloying of Ni with coke tolerant metal (i.e. Cu) and blocking of defect sites by promoter atoms (Cu, S, Au)) [1]. In the future we are aiming to study the thermal stability of coke tolerant alloys and determine the effect of other promoter atoms on coke reduction.

2. Understanding the mechanisms of sulfur poisoning of Ni-base anodes and suggestions of possible remedies for sulfur removal. To date we determined stability of sulfur on Ni surface at different coverages and the impact of sulfur on hydrogen adsorption [2]. The oxidation of adsorped sulfur on the anode surface has been also studied [3]. Interactions of sulfur with molybdenum sulfide (MoS2) as a possible alternative to Ni-based anode have been investigated [4]. In the future we are planning to study the ability of various metals (Co, Fe, W, etc.), added as a surface deposits or as alloys to Ni, to preclude sulfur poisoning. Additionally, the recovery of sulfur poisoned Ni-based anode in the oxygen, hydrogen and CO environments will be investigated.

3. Investigation of fuel (H2 and CH4) oxidation on the cermet surfaces of the anode (i.e. Ni/YSZ cermet) for the purpose of design of the coke tolerant anode. As a prerequisite we have investigated fuel oxidation on the typical oxide surfaces (ceria [5] and yttria-stabilized zirconia [6]). The following steps would include the development of kinetic model of electrochemical reactions of fuel oxidation in the triple phase boundary and the impact of alternative dopants (i.e. zirconia and ceria doped with Gd, Sm, etc.) on the rate of electrochemical reactions and oxygen transport to the anode.

1. N. M. Galea, D. Knapp, T. Ziegler, Journal of Catalysis 247 (2007) 20-33.
2. N. M. Galea, E. S. Kadantsev, T. Ziegler, J. Phys. Chem. 111 (2007) 14457-14468.
3. N. M. Galea and T. Ziegler (submitted).
4. N. M. Galea and T. Ziegler (submitted).
5. D. Knapp, T. Ziegler, J. Phys. Chem., 112 (2008) 17311-17318.
6. M. Shishkin, T. Zielger, J. Phys. Chem., 2008.

	Tom Ziegler Tom Ziegler received his Ph. D. in Inorganic/Theoretical chemistry from the University of Calgary in 1978. After obtaining two postdoctoral positions (Free University of Amsterdam and McMaster University Canada), Dr. Tom Ziegler held various positions in the University of Calgary where at present he is a professor at Chemistry department. Dr. Ziegler is a recipient of numerous awards including recent Award in Pure and Applied Chemistry (2000), Catalysis Award (2000), Fellow of the Royal Society of Denmark (2000), Canada Research Chair in Theoretical Inorganic Chemistry (2002), Schrödinger Medal Award (2004) and Steacie Award (2005). Dr. Ziegler is a co-author of 371 publications (9000 citations) since 1981. He is one of the most cited chemists in Canada and 38 in the world based statistics.
	John Lo John Lo received his Bachelor of Science with specialization in Chemistry from the University of Alberta in 2000. In 2005 he obtained his Ph. D. degree of Chemical Physics, also from the University of Alberta with the research focus on the ab initio studies of the properties of molecules in ultra-strong electrostatic and magnetic fields. He then took an Alberta Ingenuity Fellowship and worked with Professor Tom Ziegler in the University of Calgary on the project of density functional theory studies of the Fe-alloy catalyzed Fischer-Tropsch synthesis. He joined the solid-oxide fuel cell (SOFC) project since 2008; his research objectives are on the understanding, at the molecular level, of the influences of sulfur poisoning on the burning of SOFC fuels (e.g. H2 and CH4) on Ni-based anodes, and of the efficient methods of sulfur recovery using H2 and O2.
	Swati Vartak Swati Vartak obtained Master degree in Physical Chemistry in 2006 from University of Pune, India. She joined the group of Dr. Tom Ziegler at the Department of Chemistry, University of Calgary in 2006 as a Masters student. She is working on the adsorption/decomposition of H2S on different metal surfaces.
	Maxim Shishkin Maxim Shishkin received his Ph. D. in computational physics in 2002 from the De Montfort University, UK. After a year of postdoctoral position in De Montfort University, he obtained a postdoctoral position in the University of Vienna, working on development of algorithms of accurate calculations of band structures. In 2007 he jointed the group of Dr. Tom Ziegler at Chemistry department of the University of Calgary as a postdoctoral fellow. The focus of his work is an ab initio study of fuel oxidation on the electrolyte and anode surfaces in SOFC.