Additive effect of Ce, Mo and K to nickel-cobalt aluminate supported solid oxide fuel cell for direct internal reforming of methane

• Published in: The Korean journal of chemical engineering Vol. 31; no. 1; pp. 29 - 36
• Main Authors: Kwak, Bu Ho, Park, Jungdeok, Yoon, Heechul, Kim, Hyeon Hui, Kim, Lim, Chung, Jong Shik
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.01.2014; 한국화학공학회
• Subjects: Biotechnology; Catalysis; Chemistry; Chemistry and Materials Science; Industrial Chemistry/Chemical Engineering; Materials Science; Reaction Engineering; 화학공학; Nickel-cobalt Aluminate Support; Effect of Cerium; Solid-oxide Fuel Cell; Molybdenum and Potassium; Direct Internal Reforming
• ISSN: 0256-1115; 1975-7220
• DOI: 10.1007/s11814-013-0185-6

Direct internal reforming of methane (steam/carbon=0.031, 850 °C) is tested using button cells of Ni-YSZ/ YSZ/LSM in which the anode layer is supported either on Ni-YSZ or on Ni-CoAl 2 O 4 . The Ni-CoAl 2 O 4 supported cell shows little degradation with operating time, as a result of higher resistance against carbon deposition, whereas the Ni-YSZ supported cell deactivates quickly and suffers fracture in 50 h. Upon incorporation of additives such as K, Ce, or Mo into the Ni-CoAl 2 O 4 support, cells with 0.5 wt% CeO 2 exhibit the best stable performance as a result of reduced coke formation. Cells with 0.5 wt% Mo exhibit the lowest performance. Although no carbon deposit is detected in the cells with K 2 CO 3 additives, their performance is worse than that in the CeO 2 case, and, in constant-current mode, there is a sudden voltage drop to zero after a certain period of time; this time becomes shorter with increasing K content. The injection of potassium into the anode side facilitates the generation of OH − and CO 3 2− in the anode and promotes the diffusion of these ions to the cathode. Increased polarization resistance at the cathode and increased electrolyte resistance result in such a sudden failure.