An efficient construction of nano-interfaces for excellent coking tolerance of cermet anodes

Abstract

Solid oxide fuel cells (SOFCs) are promising energy conversion devices for the effective and convenient utilization of hydrocarbons (for example, methane) to electricity. However, the development of direct methane SOFCs is primarily hindered by the poor coking tolerance of the state-of-the-art Ni-based cermet anodes. Herein, we efficiently construct nano-interfaces in the anode by infiltrating a Ni0.6Y0.064Zr0.336O2-δ (NYZ) catalyst onto the traditional Ni-based cermet anode to effectively enhance the coking tolerance. After being reduced in H2, Ni and Y0.16Zr0.84O2-δ (YSZ) nanoparticles (NPs) are in situ formed on the surface of the Ni-YSZ substrate. The roughened anode demonstrates significantly improved fuel oxidation activity and coking tolerance, due likely to the formation of nano-interfaces. Specifically, when applied in the Ni-YSZ-based anode-supported SOFCs, a high peak power density of 1.785 W cm−2 and a stable operation of ∼ 240 h with no observable degradation is achieved at 750 °C in nearly dry methane (3 % H2O). A density functional theory study suggests that the excellent coking tolerance is attributed to the formation of OH species on Ni/YSZ nano-interfaces, which would further interact with intermediate carbon species to generate COH intermediates.