posted on 2024-01-26, 16:07authored byFan Liu, Hao Deng, Zixian Wang, AbdulJabbar Mohammed Hussain, Nilesh Dale, Yoshihisa Furuya, Yohei Miura, Yosuke Fukuyama, Hanping Ding, Bin Liu, Chuancheng Duan
Direct-methane solid oxide fuel cells (CH4-SOFCs) have
gained significant attention as methane, the primary component of
natural gas (NG), is cheap and widely available and the natural gas
infrastructures are relatively mature. However, at intermediate temperatures
(e.g., 600–650 °C), current CH4-SOFCs suffer
from low performance and poor durability under a low steam-to-carbon
ratio (S/C ratio), which is ascribed to the Ni-based anode that is
of low catalytic activity and prone to coking. Herein, with the guidance
of density functional theory (DFT) studies, a highly active and coking
tolerant steam methane reforming (SMR) catalyst, Sm-doped CeO2-supported Ni–Ru (SCNR), was developed. The synergy
between Ni and Ru lowers the activation energy of the first C–H
bond activation and promotes CHx decomposition.
Additionally, Sm doping increases the oxygen vacancy concentration
in CeO2, facilitating H2O adsorption and dissociation.
The SCNR can therefore simultaneously activate both CH4 and H2O molecules while oxidizing the CH* and improving
coking tolerance. We then applied SCNR as the CH4-SOFC
anode catalytic reforming layer. A peak power density of 733 mW cm–2 was achieved at 650 °C, representing a 55% improvement
compared to that of pristine CH4-SOFCs (473 mW cm–2). Moreover, long-term durability testing, with >2000 h continuous
operation, was performed under almost dry methane (5% H2O). These results highlight that CH4-SOFCs with a SCNR
catalytic layer can convert NG to electricity with high efficiency
and resilience.