Symposium FE
Fuel Cells: Materials and Technology Challenges

Session FE-1 - Solid Oxide Fuel Cells (SOFCs)

FE-1:IL01  Development and In-situ Characterization of Fast Ion Conductors for SOFCs
S. SKINNER, Imperial College London, London, UK

Understanding the process of ion transport in ceramics is critical to the development of effective and durable electrochemical devices. To fully understand these transport processes it is essential that materials are investigated in conditions as close to those experienced under operating conditions, which in itself presents a number of challenges. Recently our focus has been on the development of fast ion conductors with unusual structures and complex ion conduction processes. These features have been investigated using a range of techniques, including neutron total scattering, molecular dynamics and isotopic labelling. A number of examples will be presented highlighting the complex interplay of coordination environment with ion transport.


FE-1:IL02  Architecturally Designed La2-xPrxNiO4+δ Cathodes for SOFCs
E. DJURADO, N.I. KHAMIDY, R.K. SHARMA, Institute of Engineering Univ. Grenoble Alpes, LEPMI, Grenoble, France

Solid oxide fuel cells (SOFCs) operating at ~ 600 °C are efficient energy-conversion systems for electrical power generation. In order to design novel optimized cathodes with improved mixed ionic-electronic properties, it is of high importance to control (i) the electrode microstructure and composition to obtain large surface areas, increasing the number of active sites for the oxygen reduction reaction, (ii) the electrode/electrolyte interface to enhance the charge transfer. The present work is focused on designing Pr doped lanthanum nickelates, La2-xPrxNiO4+δ (LPNO) with 0 ≤ x ≤ 2 with the aim of finding the best compromise between chemical stability and optimized electrochemical performance. The double layer design consists of a stacking of two layers starting with a 3D tree-like microstructure over a thin dense base layer (~100 nm) fabricated in one step by electrostatic spray deposition and then topped by a screen-printed current collecting layer of the same composition. This talk will end with our latest results incorporating a composite sub-layer to the double layer LPNO electrode, to investigate the role of the electrode/electrolyte interface. The correlation between microstructure, composition, interfaces and electrical properties is discussed in detail.


FE-1:IL03  Perovskite Electrodes for SOFCs Powered by Biogas
E. DI BARTOLOMEO, University of Rome Tor Vergata, Department of Chemical Science and Technologies, Rome, Italy 

In recent years SOFCs keep attracting attention mainly for their capability of being powered by hydrocarbons or methane based mixtures. Improvements in the nanoscale engineering of anodic materials are highly required. Studies of anodes in which electron transport is provided by ceramic components rather than metals have been proposed in the last several years. The general idea is that only ceramic components can perform electron transport and oxidation catalytic activity. Ideally a mixed oxide ion and electronic conducting ceramic should be used since the ionic conductivity would serve to increase the effective size of the TPB. The electronic conductivity of the ceramic also needs to be maintained over both reducing and oxidizing conditions in order to allow for operation at both low and high fuel utilizations. Materials that have the best compromise of the desired properties seem to be perovskite type oxides. Ferrites and chromites based anodes and infiltrated perovkite anodes with different metal catalysts were developed showing regarding electrochemical performance. The catalytic activity for the dry reforming of methane reaction was investigated. A discussion on the parallelism between catalytic and electrochemical performance was detailed.


FE-1:IL04  Metal Supported Fuel Cells: Improved Electrochemical Performance by Improved Processing
M. BRAM^1,2, F. THALER^1,2, D.UDOMSILP^1,2, C. BISCHOF¹, A.K. OPITZ^1,3,  ¹Christian Doppler Laboratory for Interfaces in Electrochemcial Energy Converters; ²Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research - Materials Synthesis and Processing (IEK-1), Jülich, Germany; ³Vienna University of Technology, Institute of Chemical Technologies and Analytics, Vienna, Austria

Due to their inherent mechanical robustness, improved sealing ability and potential of cost reduction, metal supported solid oxide fuel cells (MSCs) are attractive candidates for non-stationary fuel cell applications like auxiliary powers units (APUs) or range extender for battery electric vehicles. The Christian Doppler Laboratory for Interfaces in Metal-Supported Electrochemical Energy Converters – a tight cooperation between Forschungszentrum Jülich GmbH, Vienna University of Technology, Plansee SE and AVL List GmbH – contributes to the development of the Plansee MSC concept by optimized processing of electrodes and tailoring of interfaces. On the cathode side, introduction of LSC as cathode material combined with an adaption of particle size and controlled sintering conditions were found to be effective measures to fulfill these aims. On the anode side, replacing Ni/YSZ by Ni/GDC including a stepwise optimization of microstructure and sintering conditions resulted in a significant increase of cell performance, mainly based on increasing the area of electrochemically active sites. Finally, the presentation discusses in a more general way, which factors must be considered to further improve the long-term stability of the Plansee MSC.


FE-1:L06  Analysis of Microstructural Change of Electrodes during Discharge Operation of Solid Oxide Fuel Cells
KOICHI EGUCHI, HIROKI MUROYAMA, TOSHIAKI MATSUI, Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan

The cermet of nickel and yttria-stabilized zirconia (YSZ) is widely used as an anode in solid oxide fuel cells (SOFCs). The cermet anode is subjected to the severe conditions during long term operation. Strontium-doped lanthanum manganite, (La,Sr)MnO3+δ (LSM), is one of the most common cathode materials. The microstructure of components affect the performance and stability of SOFCs. Recently the direct measurement of electrode in a three dimensional (3D) space by using focused ion beam–scanning electron microscopy (FIB–SEM) has attracted much attention as a powerful technique for microstructural analysis. This technique provides essential information to understand the quantitative relationship among the microstructure, performance, and long-term stability. In this study, then, the microstructural change in cell components with an elapsed time was quantified by the FIB–SEM technique to elucidate the degradation of anode under long term operation and the impact of initial current passage on the activation process of LSM cathode. Solid state reaction between (La,Sr)(Co,Fe) cathode and electrolyte materials has been also analyzed by FIB-SEM.


FE-1:L09  Direct Utilisation of Dry Ethanol in Solid Oxide Fuel Cells Using a Perovskite Anode Modified with Ni-alloy @ FeOx Core-shell Nanoparticles
M. LO FARO, S.C. ZIGNANI, S. TROCINO, S. MAISANO, A.S. ARICO', Institute of Advanced Energy Technologies (ITAE) - Italian National Research Council (CNR), Messina, Italy; R.M. REIS, G.G.A. SAGLIETTI, V. OLIVEIRA, E.A. TICIANELLI, Instituto de Quimica de São Carlos - USP, Brazil; N. HODNIK, F. RUIZ-ZEPEDA, National Institute of Chemistry - Ljubljana, Slovenia

Formation of carbon deposits in Solid oxide fuel cells (SOFCs) represents a relevant issue for the direct utilisation of dry organic fuels. This work investigates a new approach to address the direct oxidation of dry hydrocarbons in SOFCs. A composite multifunctional thin layer anode electrocatalyst deposited on Ni/YSZ is used as an internal integrated fuel processor. This layer is based on a Ni-modified perovskite and gadolinia-doped ceria composite. Besides the oxygen storage properties of ceria, the electrocatalyst is characterized by the presence of dispersed Ni-alloy @ FeOx core-shell nanoparticles in the outer perovskite layers and surface basicity properties. Efficient dehydrogenation of ethanol, carbon deposition-free cracking reactions and internal reforming assisted by a H2/H2O “shuttle mechanism” are the key aspects of this approach favouring the direct oxidation of ethanol in SOFCs. A power density of 0.65 W cm-2 at 0.6 V and 800 °C is achieved by feeding dry ethanol to the SOFC without evidence of carbon deposition in a durability test of more than 100 h.


FE-1:L10  Direct Addition of Lithium and Cobalt Oxide to Ce0.8Gd0.2O1.95 Electrolytes to Improve Microstructural an Electrochemical Properties in IT-SOFC at Lower Sintering Temperature
G. ACCARDO¹, D. FRATTINI², H.C. HAMC¹, S.P. YOON¹, ¹Fuel Cell Research Center, Korea Institute of Science and Technology, Seoul, South Korea; ²Graduate school of Energy and Environment, Seoul National University of Science and Technology, South Korea

To improve the microstructural and electrochemical properties of GDC electrolytes, materials co-doped with 0.5-2 mol% of lithium and cobalt oxides were successfully prepared in a one-step sol gel combustion synthetic route. Vegard’s slope theory was used to predict the dopant solubility and the sintering behaviour. The dopant addition charge and size influences the atom flux near the grain boundary with a change in the lattice parameter. In fact, compared to traditional multi grinding steps, sol gel combustion facilitates molecular mixing of the precursors and substitution of the dopant cations into the fluorite structure, considerably reducing the sintering temperature. Adding Li2O or CoO, as dopant, increases the GDC densification and reduces its traditional sintering temperature to 1000°C with an improvement in the electrochemical properties. Impedance analysis showed that the addition of 2mol% of lithium or 0.5mol% of cobalt enhances the conductivity with a consequent improvement in the cell performances. High total conductivities of 1.2·10-1 S·cm-1 and 8.7·10-2 S·cm-1 at 800°C were achieved after sintering at 1000°C for 2LiGDC and 0.5CoGDC respectively, while pure GDC sintered at the same temperature showed a lower conductivity of 1.1·10-2 S·cm-1.


FE-1:L11  Study of Materials Based on La0.6Sr0.4Fe1-yCoyO3-x for Cathodes of Intermediate Temperature Solid Oxide Fuel Cells,
(IT-SOFCs)
J. TARTAJ SALVADOR, Instituto de Cerámica y Vidrio (CSIC), Madrid, Spain

SOFCs demand lower operating conditions temperature to reduce manufacturing costs and to increase their durability. New materials are required to operate a lower temperature, i.e., the development of more effective cathode materials with increased electrocatalytic activity. La1-xSrxCoO3 (LSC) can be considered as a promising cathode for IT-SOFCs with high values of conductivity, however its use is somehow limited by a thermal expansion coefficient (TEC) mismatch with other components of the SOFC. Alternative materials are ferrite/cobaltite cathodes. The electronic conductivity of these samples in air is characterized by higher values at increasing Co contents and besides, the presence of Fe helps to minimize mechanical stresses as it can reduce the TEC mismatch. Here we show a synthetic route to easily produce a range of La0.6Sr0.4Fe1-yCoyO3-x (LSFC) at moderate temperatures. We have been able to determine on air-sintered samples how the electronic conductivity and thermal expansion coeficients change with the Fe, Co composition. The results here presented are important because they establish practical cathode operational parameters for the selection of the most suitable composition, considering the TECs of the electrolyte utilized and the operating temperature of the cell.


FE-1:L12  Bioethanol Fed Directly to Commercial Solid Oxide Fuel Cells
S. TROCINO¹, S.C. ZIGNANI¹, R.M. REIS², G.G.A. SAGLIETTI², V. OLIVEIRA²,  E.A. TICIANELLI², A.S. ARICÒ¹, M. LO FARO¹, ¹Institute of Advanced Energy Technologies (ITAE) of the Italian National Research Council (CNR), Messina, Italy; ²Instituto de Quimica de São Carlos - USP, Brazil

Solid oxide fuel cells (SOFCs) based on conventional nickel-yttria stabilized zirconia (Ni-YSZ) anodes can not be fed directly with organic fuels because of the associated formation of carbon deposits. This presentation explores a simple approach to solve such relevant limiting factor that affects the utilization of dry biofuels such as ethanol and glycerol directly fed in SOFCs. The approach consists in depositing a composite multifunctional electrocatalyst layer on the SOFC anode to work as an internal integrated fuel processor. A protective layer based on a composite made of Ni-modified perovskite and gadolinia-doped ceria is coated on a conventional SOFC anode based on Ni-YSZ. Beside the oxygen storage properties of ceria, the composite electrocatalyst is characterized by the presence of FeCoNiOx nanoparticles in the outer layers and surface basicity properties based on a Ruddlesden-Popper phase. Efficient dehydrogenation mechanism, carbon deposition-free cracking reactions and internal reforming assisted by a H2/H2O “shuttle mechanism” appear as the key steps involved in the direct oxidation of the biofuels at the modified SOFC anode.


FE-1:L14  Robust Nano-particles on Active Perovskite Oxide Anode for Solid Oxide Electrochemical Cells
TAE HO SHIN, HANBIT KIM, Korea Institute of Ceramic Engineering & Technology, Jinju-si, South Korea

Nano-structured surfaces, such as supported nano-wires, nano-tubes, nano-rods, nano-sheets, or nano metal particles have considerable potential to solve several key challenges which catalysis and renewable energy are currently facing, provided that their morphology and hence catalytic activity can be controlled during preparation but also during operation. In particular, the use of nanoparticles in solid oxide electrochemical cells has been considered problematic because the nano-structured surface typically prepared by deposition techniques may easily coarsen and thus deactivate, especially when used in high temperature redox conditions. Recently we have shown that perovskite lattice defects in general and built-in A-site vacancies in particular, are instrumental for tailoring several aspects related to exsolution, including particle nucleation, size, distribution, stronger interaction with the parent support, and can also enable a wider range of species to be ex-solved more reliably, including for instance, transition metal Here we show that robust transition metal nano complex grown in situ from specifically designed nonstoichiometric perovskites or extreme nano ceria share a uniquely strong interaction with the parent support and form a well-functioning solid oxide electrolyte.


Session FE-2 - Proton-conducting (PEFCs) and Alkaline (AFCs) Polymer Electrolyte Fuel Cells

FE-2:IL01  Anion Exchange Membranes, Stable in Hot Caustic Solutions
S. HOLDCROFT, Department of Chemistry, Simon Fraser University, Burnaby, Greater Vancouver, BC, Canada

Perfluorinated proton-exchange polymers form the basis of standard high-performance PEMFCs but difficult synthetic chemistry hampers further materials development. Hydrocarbon proton-exchange materials, on the other hand, are founded on well-established and versatile synthetic chemistry that allows for rapid materials development, and offer a less expensive alternative to perfluorinated polymers. In the corollary case of Anion Exchange Membrane Fuel Cells, the search continues for an alkaline-stable, polymeric hydroxide-conducting medium. Solutions to these challenges require the undertaking of rigorous systematic studies on model polymers and representative materials of known and controllable molecular structure and preferred nano-morphology. In this presentation, the evolution and properties of unique hydroxide-conducting polymers being developed at Simon Fraser University will be described.


FE-2:IL02  Mößbauer Spectroscopy in Fuel Cell Electrocatalysis of Non-precious Metal Catalysts
U.I. KRAMM, TU Darmstadt, Catalysts and Electrocatalysts, Darmstadt, Germany

Commercialization of fuel cell cars is greatly hampered by the high costs of platinum based catalysts. Fe-N-C catalysts are so far the most promising alternative for the replacement of platinum on the cathode. The structural constitution of such catalysts is significantly different in comparison to platinum based catalysts: The oxygen reduction reaction (ORR) takes place at molecular FeN4-sites instead of nanoparticles typically found for platinum and its alloys. That is why different techniques have to be applied for structural characterization in order to enable insights into structure-activity and structure-stability correlations. Mößbauer spectroscopy is the most powerful technique for the characterization of iron species. Therefore, this talk will focus on our recent results using Mößbauer spectroscopy in combination with other techniques for the characterization of Fe-N-C catalysts.


FE-2:IL04  Nano-structured Hydrogen Oxidation Electrocatalysts for Anion Exchange Membrane Fuel Cells
H.A. MILLER, A. LAVACCHI, F. VIZZA, M. BELLINI, M. FOLLIERO, M. PAGLIARO, J. FILPI, A. MARCHIONNI, M. MARELLI, F. DI BENEDETTO, F. D’ACAPITO, D.R. DEKEL, CNR-ICCOM, Sesto Fiorentino, Italy

One of the biggest obstacles to the diffusion of fuel cells is their cost, a large part of which is due to platinum (Pt) electrocatalysts. Complete removal of Pt is a difficult if not impossible task for proton exchange membrane fuel cells (PEM-FCs). The Anion Exchange Membrane Fuel Cell (AEM-FC) has long been proposed as a solution as non-Pt metals may be employed. Despite this, few examples of Pt free AEM-FCs have been demonstrated with modest power output. The main obstacle preventing the realization of a high power density Pt free AEM-FC is sluggish hydrogen oxidation (HOR) kinetics of the anode catalyst. Here we describe a Pt free AEM-FC that employs a mixed carbon-CeO2 supported palladium (Pd) anode catalyst that exhibits enhanced kinetics for the HOR. AEM-FC tests run on dry H2 and pure air show peak power densities of more than 500 mW cm-2.


FE-2:IL05  Proton Conductivity in Intermediate Temperature Electrolyte Membranes - New Insights and Perspectives
QINGFENG LI, D. AILI, H. BECKER, L.N. CLEEMANN, J.O. JENSEN, Section of Proton Conductors, Department of Energy Conversion and Storage, Technical University of Denmark, Lyngby, Denmark

Acid-base polymer membranes represent an effective approach to achieving intermediate temperature operation of PEM fuel cells preferably under ambient pressure. Phosphoric acid doped polybenzimidazole membrane seems so far the most successful system in the field. The proton conductivity of the acid doped membrane has long been hypothesized to be via the Grotthuss hopping mechanism. New insight is recently achieved showing significance of the vehicle mechanism and mobility of the ionic and molecular acid species, based on which success and failure of the acid-base membranes as well as the impact on fuel cell operation and durability will be discussed. It is proposed that the acidity matching between the acid and base components dictates the ionicity and extent of the hydrogen bond network and therefore the proton dynamics and conductivity mechanism. Recent progress in improving the long-term durability of the membranes and fuel cells at further elevated temperatures will be reported and perspectives of the materials and fuel cell technology are outlined.


FE-2:IL06  State-of-the-art polymer Electrolyte Fuel Cells (PEFC): The Remaining Research Challenges
K.A. FRIEDRICH, P. GAZDZICKI, J. MITZEL, M. SCHULZE, German Aerospace Center (DLR), Institute of Engineering Thermodynamics, Stuttgart, Germany; R. HIESGEN, University of Applied Sciences Esslingen, Department of Basic Science, Esslingen, Germany

Fuel cell technology has progressed significantly regarding performance and durability during the last decade. The remaining challenges will be discussed during this presentation. The presentation focuses on investigations of fuel cell durability and degradation at low Pt loadings. Major motivation is the need to reduce the amount of Pt in MEAs down to below 0.2 mgPt/cm2 in order to make PEFC more competitive and sustainable. The particular challenge is to maintain high performance and long-term durability concurrently with the Pt loading reduction which are conflicting goals. In this context, a general problem is the lack of common procedures to reliably determine voltage loss rates in durability tests and to distinguished irreversible and reversible voltage losses. Regarding the influence of Pt loading on PEFC performance and durability our study shows that for cathode loadings below 0.2 mgPt/cm2 and for current densities >1 A/cm2, a sudden increase of mass transport resistance is observed. The same threshold value is found for the increase of irreversible voltage losses. These results are discussed with respect to the electrode structure, in particular with respect to the ionomer in the electrode.


FE-2:IL08  Cobalt Platinum Bronze as a Catalyst for Polymer Electrolyte Fuel Cells
YUJI KAMITAKA, YU MORIMOTO, Toyota Central R&D Labs., Inc., Nagakute, Aichi, Japan

An electron-conducting mixed oxide, cobalt platinum bronze (Co-Pt bronze), was synthesized by a solid state reaction followed by hot aqua regia treatment and evaluated as electrochemical catalysts for oxygen reduction reaction and oxygen evolution reaction.. The ORR specific activity of the obtained catalyst was comparable to Pt/Vulcan after potential cycling (0.05-1.2 V) owning to thin metallic platinum layer formed on the surface of Co-Pt bronze. Co-Pt bronze showed high stability for high potential and potential cycles. In addition, the OER activity of Co-Pt bronze was also found high and stable.


FE-2:IL11  Platinum Dissolution: From Model Surfaces to Applied Fuel Cell Catalysts
S. CHEREVKO, Forschungszentrum Jülich GmbH, Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Erlangen, Germany

Dissolution of platinum is still one of the major obstacles in the spreading of proton exchange membrane fuel cells (PEMFC) – it is the main cause of the cell efficiency decrease with time. For many years now, it is extensively investigated on both the device level and the simplified catalyst level. In order of complexity increase, the latter can be ordered as follows: Pt low indexes single crystals; polycrystalline Pt; Pt nanoparticles; supported Pt nanoparticles, where the last one is closely reminding the catalyst layer of PEMFC. Over last years all these systems were investigated in our group in order to understand the complex mechanism of Pt dissolution. An inductively coupled plasma mass spectrometer (ICP-MS) directly connected to an electrochemical scanning flow cell (SFC) was used for time- and potential-resolved Pt dissolution analysis. In this talk I am going to present the most important results of this research. The main focus will be put on the understanding of the influence of system complexity and experimental parameters, simulating cell operational conditions, on Pt dissolution, with a final goal to clarify how the results on Pt dissolution from model catalysts can be extrapolated to PEMFCs.


FE-2:L12  Remaining Challenges in Anion Exchange Membrane Fuel Cells
D.R. DEKEL, Technion - Israel Institute of Technology, Haifa, Israel

After a decade of development of Anion Exchange Membrane Fuel Cells (AEMFCs) we can now remark the substantial progress that has been made in cell performance (AEMs) [1]. However, AEMFC is still far from practical use. Among the main remaining challenges AEMFC technology should soon overcome to be considered a real power source alternative, are the ability to work with (A) ambient air [2], (B) non-PGM hydrogen oxidation electrocatalysts [3-4], and mainly, (C) to keep high cell performance during time [5]. Among them, performance stability is the most critical challenge. Recent advances in the development of ex-situ techniques that enable cation stability measurement in an environment that simulates the in-situ environment of an AEMFC in operation are now available [6-7]. We believe that these new methods to measure material stability will soon lead to the development of stable materials for durable AEMFCs.
1. Varcoe et al, EES 7, 3135, 2014. 2. Krewer et al, Electrochim. Acta, 2017. 3. Alesker et al, J. Power Sources 304, 332, 2016. 4. Miller et al, Angew. Chem. 128, 6108, 2016; Nano Energy 33, 293, 2017. 5. Dekel; J. Power Sources 2017, DOI:10.1016/j.jpowsour.2017.07.117. 6. Dekel et al, Chem. Mater. 29, 4425, 2017; J. Power Sources 2017, DOI:10.1016/j.jpowsour.2017.08.026


Session FE-3 - Direct Alcohol Fuel Cells (DAFCs)

FE-3:L01  Ru-modified Carbons by Organometallic Functionalization as Support for Nanostructured Pt: High Performance Pt-Ru Catalysts for the Oxidation of Methanol and Ethanol in Alkaline Media
E. CANDIA-GARCIA¹, J.A. DIAZ-GUILLEN¹, J.C. MARTINEZ-LOYOLA², A.A. SILLER-CENICEROS³, M.E. SANCHEZ-CASTRO³, M. SANCHEZ-VAZQUEZ⁴, B. ESCOBAR-MORALES⁵, I.L. ALONSO-LEMUS⁶; F.J. RODRIGUEZ-VARELA³, ¹Instituto Tecnológico de Saltillo, Saltillo, Coahuila, México; ²Universidad Tecnológica de Coahuila, Ramos Arizpe, Coahuila, México; ³Sustentabilidad de los Recursos Naturales y Energía, Cinvestav Unidad Saltillo, Ramos Arizpe, Coahuila, México; ⁴Centro de Investigación en Materiales Avanzados, PIIT, Apodaca, NL, México; ⁵CONACYT, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, México; ⁶CONACYT, Sustentabilidad de los Recursos Naturales y Energía, Cinvestav Unidad Saltillo, México

Commercial Vulcan XC-72 (C) and reduced Graphene oxide (RGO), and home-developed AB7 (from waste leather), were functionalized with [(η6-C6H5OCH2CH2OH)RuCl2]2 (Ru-dim) and [(η6-MeC6H4iPr)RuCl2]2 (Ru-cym). Functionalized-carbons were applied as support to obtain Pt/C, Pt/RGO and Pt/AB7 catalysts by the polyol method. Their catalytic activity was evaluated for the Methanol and Ethanol Oxidation Reactions (MOR and EOR). FT-IR analysis of the functionalized supports showed the presence of OH, C-H, C-C, C-O surface functional groups. Surface modification has been achieved to a larger extent with Ru-dim. Raman characterization indicated that the sp2 domains of the carbons remained almost unchanged, thus their graphitized lattice were no distorted after functionalization. The nanostructured nature of the Pt/CRu-dim, Pt/CRu-cym, Pt/RGORu-dim, Pt/RGORu-cym, Pt/AB7Ru-dim and Pt/AB7Ru-cym nanocatalysts was confirmed by XRD. Electrochemical characterization in 0.5 mol L-1 KOH showed that in most cases organometallic functionalization promotes the reactions. Overall, interactions of Pt with Ru atoms from Ru-dim resulted in a higher catalytic activity relative to Ru-cym. Pt/AB7Ru-dim delivered the highest performance for the MOR. Meanwhile, Pt/CRu-dim was the most active catalyst for the EOR.


FE-3:L02  Synthesis and Characterization of Co-N-C and Fe-N-C for Application as Methanol Tolerant Catalysts in DMFCs
C. LO VECCHIO, G. MONFORTE, A.S. ARICÒ, V. BAGLIO, Istituto di Tecnologie Avanzate per l'Energia "Nicola Giordano" (ITAE-CNR), Messina, Italy

Oxygen reduction reaction (ORR) is one of the most important processes for fuel cell. Platinum and other noble metals are suitable materials able to catalyze the ORR in a fuel cell. However, because of the cost, PEMFC and DMFC technologies requires the development of non-precious-metal catalysts (NPMC) characterized by efficient activity and selectivity towards ORR. In this regard, Co-N-C and Fe-N-C have been prepared by, first, chelating the metals with ethylene diamine tetra acetic acid (EDTA, nitrogen precursor). In the next step, the chelated metals have been deposited on a high surface area oxidized carbon support to increase the electrical conductivity. The latter composite material has been thermally treated at 800°C (CoNC8 and FeNC8) or 1000°C (CoNC10 and FeNC10) in nitrogen atmosphere in order to create the catalytic sites that will be able to perform the oxygen reduction reaction (ORR). Rotating disk electrode (RDE) measurements have been carried out to investigate the activity and stability of the electro-catalysts for the ORR. Information about the structure, morphology, surface characteristics has been obtained by XRD, TEM and XPS, whereas the elemental composition has been studied by CHNS and EDX. The most promising formulations have been investigated in DMFCs.


FE-3:L03  Activity and Degradation Study of a Fe-N-C Catalyst for ORR in Direct Methanol Fuel Cell (DMFC)
I. MARTINAIOU^{1, 2}, A.H.A. MONTEVERDE VIDELA³, S. SPECCHIA³, U.I. KRAMM^{1, 2}, ¹TU Darmstadt, Catalysts and Electrocatalysts, Dept. of Materials- and Earth Science and Dept. of Chemistry, Darmstadt, Germany; ²Graduate School of Excellence Energy Science and Engineering, Darmstadt, Germany; ³Politecnico di Torino, Dip. Scienza Applicata e Tecnologia, Torino, Italy

The growing demand for renewable energy sources gives plenty of space to the field of electrocatalysis. Especially in the transportation sector, low temperature fuel cells are of interest. In a Direct Methanol Fuel Cell (DMFC) one major problem that strongly limits the performance of DMFCs is the methanol cross-over that leads to a poisoning of Pt-based catalysts for the ORR. For different low-temperature fuel cells Fe-N-C catalysts have reached promising performance [1-3]. Several publications show that in contrast to Pt, Fe-N-C catalysts exhibit an exceptional tolerance towards methanol [4]. While there are some studies on the impact of FC performance on Fe-N-C degradation in PEFC, almost no data are available on the structural changes of Fe-N-C in DMFC. In this contribution we present the results of performance, durability and structural characterization of a Fe-N-C catalyst during DMFC testing with varying the temperature of the system. In addition we confirm the negligible effect of methanol crossover on the cathode side when using a NPMC [4].
[1] E. Proietti, et al., Nat.Comm. (2011), 2, 416. [2] A. Serov, et al., NanoEnergy (2015), 16, 293. [3] I. Martinaiou, T. Wolker, et al., J. of Power Sources (2017) [4] A.H.A Mondeverde Videla, et al., Int. J.Hydr Energy (2016),41.


FE-3:IL04  Electrocatalyst Supports for Direct Methanol Fuel Cells
M.V. MARTINEZ-HUERTA, Institute of Catalysis and Petrochemistry, CSIC, Madrid, Spain

Direct methanol fuel cells (DMFCs) have been extensively studied as ideal energy converters that convert chemical energy of methanol directly to electrical energy. Methanol, as a liquid fuel at ambient conditions, possesses significant advantages such as high solubility in aqueous electrolytes, high energy density and it is easily stored, transported, and handled by the existing infrastructure. However, for the implementation of this technology, the development of good electrocatalysts for alcohol electrooxidation is necessary. Pt-based materials are being commonly used because of their unique catalytic activity. The nanoparticles are usually supported in electrical conductive carbons in order to increase the accessibility of the active sites. But conventional carbon supports are not stable enough, as suffer from corrosion during electrochemical process. For that reason, the research on exploring the use of novel nanocomposites in fuel cells is growing rapidly. Herein, nanocomposites obtained from combinations of polymer-carbon and ceramic-carbon materials as Pt catalyst supports for methanol oxidation have been studied. The enhanced properties of the hybrid support resulted in a high performance and stability of the catalysts.


FE-3:IL05  Understanding Water and Methanol Transport Properties in Ionomers and Composite Membranes Based on Non-fluorinated Polymers for Fuel Cell Applications
I. NICOTERA, C. SIMARI, Dept. of Chemistry and Chemical Technology, University of Calabria, Rende (CS), Italy; A. ENOTIADIS, National Center for Scientific Research “Demokritos”, Athens, Greece

Direct methanol fuel cells are fed with relatively safe and regenerative liquid, but suffer of limited operation temperature and fuel cross-over. In fact, the methanol permeation through the electrolyte reduces the cell efficiency. Many efforts are devoted in the development of alternative electrolyte membranes to commercial Nafion, and this talk will focus on non-fluorinated ionomers operating in the same temperature range and with much lower crossover. Important requirements are adequate mechanical strength with respect to the levels of functionalization (generally sulfonation) as well as of hydration, allowing high proton conductivity and stability in the aggressive environment of a working fuel cell. For this purpose, hybrid nanocomposites based on highly hydrophilic nanoadditives such as Layered Doubled Hydroxide and Nanoscale Ionic Materials (NIMs) are also proposed. NMR spectroscopy is widely used to investigate molecular dynamics and proton transport mechanisms through direct measurements of self-diffusion coefficients (PFG) and relaxation times, in order to achieve a systematic understanding at a fundamental level of the effects of dimensionality and organization of these nanofillers on the physico-chemical, mechanical and conductivity properties of the ionomers.


FE-3:IL06  Catalysts with Low Noble Metal Content for Ethanol Electro-oxidation
N. SHAKIBI NIA, C. RÜDIGER, A. PADUANO, G. GARCÍA, A. MARTUCCI, E. PASTOR, G. GRANOZZI, J. KUNZE-LIEBHÄUSER, Institut für Physikalische Chemie, Leopold-Franzens-Universität Innsbruck, Innsbruck, Austria; Department of Industrial Engineering, University of Padova, Padua, Italy; Instituto de Materiales y Nanotecnología, Universidad de La Laguna, La Laguna, Spain

Direct Ethanol Fuel Cells (DEFC) have been the subject of numerous studies in recent years, however, the complete oxidation of ethanol to CO2 at the anode side is still one of the main challenges. Efficient electro oxidation of ethanol (EOR) requires the use of expensive platinum based electrodes. Moreover, the catalysts are mainly supported on carbon, which can corrode under certain conditions resulting in detachment and agglomeration of catalyst nanoparticles [1]. In this study, titanium oxycarbide (TiOC), molybdenum and tungsten carbides (MoxC, WxC) are investigated as innovative supports for platinum and platinum alloy nanoparticles during the EOR. The chemical composition of the catalyst surfaces is characterized using X-ray photoelectron spectroscopy (XPS). The activity of the catalysts is determined using cyclic voltammetry (CV), and current transients are recorded at temperatures up to 70 °C in acidic electrolytes. For a quantitative evaluation of the EOR products, online differential electrochemical mass spectrometry (DEMS) is employed. Adsorbed intermediates are identified in operando with infrared reflection absorption spectroscopy.
[1] Gallagher, K.G.; Darling, R.M.; Fuller T.F.; Handbook of Fuel Cells: John Wiley & Sons, Ltd; 2010.


FE-3:IL07  Nano-sized Platinum-free Electrocatalysts in Alkaline Direct Alcohol Fuel Cells: Catalyst Design and Principles
K.I. OZOEMENA, Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, South Africa

Alkaline direct alcohol fuel cells (ADAFCs) have continued to be recognised as viable power sources for consumer and portable electronics. Unlike the conventional proton exchange membrane fuel cells (PEMFCs), ADAFCs use liquid fuels which are easier to handle and with higher volumetric energy densities compared to hydrogen. Developments in ADAFCs depend on the use of high-performance low-cost Pt-free electrocatalysts [1,2]. In this presentation, the author will attempt to provide some answers to important questions that researchers in the ADAFC field ask (or should be asking) such as “What are the underlying principles that must inform our choice in designing such a catalyst?”, and “What synthesis method(s) or catalyst supports should be considered to prepare the catalysts with the appropriate physico-chemical properties for high-performance?”
[1] K.I. Ozoemena, RSC Advances 2016, 6, 89523. [2] Nanomaterials for Fuel Cell Catalysis (Edited by Kenneth I. Ozoemena and Shaowei Chen), Springer Publishing, New York, USA, (ISBN: 978-3-319-26249-9) 2016.