Combustion-synthesized Ru–Al 2O 3 composites as anode catalyst layer of a solid oxide fuel cell operating on methane

Abstract

Ru–Al 2O 3 composites with varied Ru contents were synthesized by a glycine–nitrate combustion technique. Their potential application as anode catalyst functional layer of a solid–oxide fuel cell operating on methane fuel was investigated. Catalytic tests demonstrated the 3–7 wt.% Ru–Al 2O 3 composites had high catalytic activity for methane partial oxidation and CO 2/H 2O reforming reactions, while 1 wt.% Ru–Al 2O 3 had insufficient activity. The 3 wt.% Ru–Al 2O 3 catalyst also showed excellent operation stability and good thermal–mechanical compatibility with Ni–YSZ anode. H 2-TPR and TEM results indicated there was strong interaction between RuO x and Al 2O 3 in the as-synthesized catalysts, which may account for the good catalytic stability of 3 wt.% Ru–Al 2O 3 catalyst. O 2-TPO results demonstrated Ru–Al 2O 3 also had excellent coking resistance. Furthermore, the carbon deposited over Ru–Al 2O 3 had lower graphitization degree than that deposited over Ni–Al 2O 3, suggesting the easier elimination of potential carbon deposited over the Ru–Al 2O 3 catalysts. A cell with 3 wt.% Ru–Al 2O 3 catalyst functional layer was prepared, wh-ich delivered peak power densities of 1006, 952 and 929 mW cm −2 at 850 °C, operating on methane–O 2, methane–H 2O and methane–CO 2 gas mixtures, respectively, comparable to that operating on hydrogen fuel. It highly promised 3 wt.% Ru–Al 2O 3 as a coking resistant catalyst layer for solid–oxide fuel cells.