Evidence of anti-coking behavior of La0.8Sr0.2Cr0.98Ru0.02O3 as potential anode material for Solid Oxide Fuel Cells directly fed under methane

La0.8Sr0.2Cr0.98Ru0.02O3 catalyst surface after 24h of steam reforming of methane in water-deficient conditions. No carbon deposition and no deterioration of catalyst are observed during test. This catalyst appears therefore as a promising anode material for SOFCs operating with natural gas and using the gradual internal methane reforming concept. [Display omitted] ► Ru0 deactivates during methane steam reforming in water-deficient conditions. ► Ru4+ inserted in perovskite structure (LSCRu) is active and stable. ► No carbon deposition is observed on LSCRu even after 72h of test. ► No deterioration of LSCRu catalyst is observed even after 72h of test. ► Residual steam plays a key role in catalytic activity of LSCRu. La0.8Sr0.2CrO3 (LSC) based Ru catalysts are very active in methane steam reforming. Nevertheless, they can be easily poisoned under water-deficient conditions. Ru can be deposited as metallic ruthenium particles decorating the LSC grains or be inserted as Ru ions in the perovskite structure. Both Ru-promoted LSC catalysts were studied in methane steam reforming under water-deficient conditions and characterized after testing. Catalytic activity tests showed that ruthenium metal species are deactivated under water-deficient atmosphere, while ruthenium species inserted in LSC presented a remarkable stability and catalytic activity where residual steam plays a key role. Very unreactive carbon species responsible for deactivation were detected by temperature-programmed oxidation and transmission electron microscopy over metallic ruthenium species. Such species were not observed when ruthenium species are inserted and stabilized into the LSC structure. La0.8Sr0.2Cr0.98Ru0.02O3 appears therefore as a highly promising anti-coking anode material for Solid Oxide Fuel Cells directly fed with methane or natural gas and operating under water-deficient conditions.