Electrocatalytic Performance and Carbon Tolerance of Ternary Au–Mο–Ni/GDC SOFC Anodes Under CH4 – Rich Internal Steam Reforming Conditions
Authors: Niakolas Dimitrios K. , Neophytides Stylianos G. , Neofytides Charalampos S. 
Published: February 2020

Solid Oxide Fuel Cells (SOFCs) are a viable high temperature fuel cell technology, which converts chemical energy directly into electricity with high efficiencies. Some of their main advantages are: (i) the enhanced reaction kinetics due to the wide range of operating temperature (500 – 1000 °C) and (ii) their fuel feed flexibility [1]. In particular, SOFCs have the ability to operate directly with various hydrocarbon (H/C) fuels, without the need of an external reformer. This type of operation, known as Internal Reforming (I.R.), is based on the catalytic activity of the fuel exposed electrode and it is one of the competitive advantages for the commercialization of this technology. Several fuels can be considered as candidates including Natural Gas (N.G.) and biogas [1, 2]. One of the basic drawbacks is that these fuels comprise various carbon components, which poison and deactivate the State of the Art (SoA) SOFC anodes [1]. Currently, the SoA anodes comprise Ni-based materials, which face various degradation issues. Indicatively: (i) they are prone to carbon deposition, formed by decomposition of e.g. CH4 or by CO disproportionation, (ii) they present poor redox stability and (iii) nickel forms agglomerates after prolonged fuel cell operation [1]. Thus, worldwide research focuses on the development of efficient and tolerant anode materials, against carbon deposition, where controlling the anode`s microstructure is essential for improving its performance [1]. Recent attempts from our group [1, 3-5] to modify NiO/GDC anode powders with Au and/or Mo nano-particles, resulted in electrodes with high tolerance and improved electrocatalytic activity under carbon forming conditions. The present study deals with comparative results of electrocatalytic measurements on SOFCs with Ni/GDC and Au-Mo-Ni/GDC as anodes for the CH4 internal steam reforming reaction (ISR), under CH4-rich conditions and specifically without dilution of the reactants in a carrier gas. The objectives were to investigate the induced effects from the Au-Mo- modification on the carbon tolerance of Ni/GDC and the subsequent performace of this cermet as anode electrode in SOFCs.

Acknowledgments

The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under the project T-CELL with Grant Agreement n° [298300].

References

[1] D.K. Niakolas, Applied Catalysis A., 486 (2014) 123.
[2] A. Hagen, Journal of the Electrochemical Society, 160(2) (2013) F111.
[3] D.K. Niakolas, M. Athanasiou, V. Dracopoulos, I. Tsiaoussis, S. Bebelis, S.G. Neophytides, Applied Catalysis A., 456 (2013) 223.
[4] D.K. Niakolas, J.P. Ouweltjes, G. Rietveld, V. Dracopoulos, S.G. Neophytides, International Journal of Hydrogen Energy, 35 (2010) 7898.
[5] S. Souentie, M. Athanasiou, D.K Niakolas, A. Katsaounis, S.G Neophytides, C.G. Vayenas, Journal of Catalysis 306 (2013) 116.