A molten carbonate fuel cell (MCFC) is ultraclean and a suitable solution for stationary power generation. In general, a temperature of approximately 650 °C is required for sufficient conductivity within the carbonate electrolyte. Aside from electricity, heat is also produced by electrochemical reactions. Therefore, by combining an electrochemical cell producing heat with a reforming reactor, direct internal reforming (DIR) is possible, where DIR directly utilizes the heat and steam produced by electrochemical reactions. Thus, DIR has advantages regarding the overall efficiency and CH4 conversion. However, a significant challenge for DIR is deactivating the reforming catalyst that occurs when the catalyst is in contact with alkali metals. The presence of steam transforms the molten carbonate electrolytes into alkali hydroxide vapors, thereby depositing them onto the DIR catalysts. Therefore, the main issue for DIR is to develop an alkali resistant catalyst.

Ni/Al2O3 yolk-shell catalysts were prepared by different procedure for DIR with alkali poisoning. Yolk-shell (ys) and porous yolk-shell (pys) materials were synthesized using a spray pyrolysis process. The physicochemical and structural properties of the prepared catalysts on the reaction performance and alkali resistance were investigated. All the yolk-shell catalysts exhibited high resistance to carbon deposition. The Ni/pys-Al2O3 catalyst showed the highest CH4 conversion and the best stability at a gas hourly space velocity of 932,492 mL⋅g−1⋅h−1 even upon exposure to alkali hydroxide vapor. It also showed strong resistance to sintering, whereas the structures of the ys-Ni-Al2O3 and Ni/ys-Al2O3 catalysts were relatively degraded under the same conditions.

[Reference] Kyung-Won Jeon, Jin Koo Kim, Beom-Jun Kim, Won-Jun Jang, Yun Chan Kang, Hyun-Seog Roh, (2023) “Ultra-stable porous yolk-shell Ni catalysts for the steam reforming of methane with alkali poisoning” Chemical Engineering Journal, DOI:10.1016/j.cej.2022.140060 

[Main Author] Kyung-Won Jeon(Kyungnam University), Jin Koo Kim(Korea University), Won-Jun Jang(Kyungnam University), Yun Chan Kang(Korea University), Hyun-Seog Roh(Yonsei University)

* Contact : Prof. Hyun-Seog Roh (hsroh@yonsei.ac.kr), Prof. Yun Chan Kang (yckang@korea.ac.kr), Prof. Won-Jun Jang(wjjang@kyungnam.ac.kr)