Carbon doping of ceria-supported palladium for the low-temperature oxidation of methane

Cerium oxide-supported palladium nanoparticles (Pd/CeO2) are poorly active toward the remediation of lean-burn exhausts at a cold start (operation temperature <300 & DEG;C) due to the presence of excessive palladium oxide (PdO) over the surface. Pd/CeO2 was prepared by the wetness-impregnation method and subjected to a gas stream of methane (CH4) and oxygen (O-2) at 230 & DEG;C. The supported Pd nanoparticles were partly converted to palladium carbide (PdCx) due to carbon doping during this atmosphere treatment. This atmosphere-treated Pd/CeO2 material exhibited improved catalytic performance towards remediation of a simulated lean-burn exhaust containing CH4 and excessive O-2. Comprehensive characterization (scanning transmission electron microscopy, X-ray photoemission spectroscopy, thermogravimetry analysis/differential thermal analysis) of the material demonstrated that the improved catalytic performance of atmosphere-treated Pd/CeO2 could be attributed to the oxidative decomposition of PdCx species during catalysis, which created surface Pd sites to promote remediation of the lean-burn exhaust at <300 & DEG;C.

Automated summary

Atmosphere-treated Pd/CeO2 shows improved catalytic performance in the remediation of lean-burn exhausts at temperatures <300℃. The improvement is attributed to the oxidative decomposition of PdCx species during catalysis, which creates surface Pd sites to promote the remediation process.