Origin of sulfur tolerance in Mo-decorated Ni anodes: preferential adsorption and structural reversibility

Solid oxide fuel cells (SOFCs) operating on sulfur-containing hydrocarbons suffer from rapid poisoning of conventional Ni-based anodes. Herein, we report a synergistic design integrating a Mo-mediated sacrificial capture mechanism with a hierarchical hybrid-pore microstructure. Mo acts as a preferential thermodynamic trap with a significantly stronger H 2 S adsorption energy (−1.07 eV) than Ni (−0.61 eV), lowering the local sulfur chemical potential to suppress nickel sulfidation. This effect is amplified by the hybrid-pore microstructure, reducing H 2 S concentrations from 120 to 14 ppm. Furthermore, we demonstrate an in-situ regeneration mechanism where sulfidized Mo phases dynamically regenerate, ensuring continuous catalysis. This dual strategy of capture and regenerability yields exceptional resilience in sulfur-laden hydrogen and methanol over 300 h. Stable operation limits are extended by 2.6- and 2.3-fold, respectively, suppressing the degradation rate to 0.4 mV h −1 . This establishes a fundamental pathway for designing robust anodes for direct hydrocarbon SOFCs.