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Ammonia is regarded as a promising alternative fuel for solid oxide fuel cells (SOFCs) compared with hydrogen due to its low cost and ease for transportation and storage. The conventional anode Ni/yttria-stabilized zirconia (Ni/YSZ) of SOFCs can serve as an efficient catalyst for ammonia decomposition at high temperatures above 700 °C but its catalytic activity decreases rapidly at lower temperatures, leading to an undesirable degradation of cell performance. Here we report a low-temperature ammonia decomposition catalyst Ba-modified Ni/yttria-stabilized zirconia (Ba-Ni/YSZ) prepared by a one-pot solid-liquid (SL) method. Enhanced performance can be obtained for Ba-Ni/YSZ compared with that of Ni/YSZ catalysts, indicating that the addition of Ba promotes the catalytic activity. X-ray photoelectron spectroscopy (XPS) and Temperature-programmed reduction with H2(H2-TPR) characterizations of Ba-Ni/YSZ catalysts indicate that Ba changes the electronic structure of Ni and facilitates the interaction between Ni and support. The kinetics analysis demonstrates that the modification by a small amount of Ba species alleviated the negative effect of the hydrogen poisoning on the active sites of Ni/YSZ catalysts. Besides, the Ba-Ni/YSZ catalyst is introduced into the flat-tube SOFC with symmetric double-sided cathodes (DSC), and significantly improves the electrochemical performance of directly ammonia-fed DSC cells at low temperatures. [ABSTRACT FROM AUTHOR]

The La0.8Sr0.2MnO3-δ (LSM)-coated Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) cathode with 3D core-shell architecture has been fabricated by the solution impregnation technology. On the basis of previous research, the synthetic process is improved in order to promote the perovskite degree of BSCF. In this paper, the oxygen reduction reaction (ORR) mechanism of LSM-coated BSCF is studied in detail. As the intervention of LSM shell, the LSM-coated BSCF presents the different ORR rate-determining step comparing with the BSCF cathode. The formation and transfer of lattice oxygen in LSM is the rate-determining step for the LSM-coated BSCF cathode, while the molecular oxygen surface adsorption for the BSCF cathode. In the single cells test, the LSM-coated BSCF cell shows a higher maximum power density than the uncoated cell. The remarkable CO2-poisoning resistant performance of LSM-coated BSCF is verified by the CO2-TPD test and the single cell potentiostatic test. The excellent electrochemical performance and CO2-poisoning resistance indicate that LSM-coated BSCF cathode appears to be a promising cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). [ABSTRACT FROM AUTHOR]