Core-shell structured Ru-Ni@SiO₂: Active for partial oxidation of methane with tunable H₂/CO ratio

This study demonstrated that a Ru-Ni bimetallic core-shell catalyst (0.6%Ru-Ni)@SiO₂ with a proper surface Ru concentration is superior in achieving better catalytic activity and tunable H₂/CO ratio at a comparatively lower reaction temperature (700 °C). Compared to the impregnation method, the hydrothermal approach leads to a highly uniform Ru distribution throughout the core particles. Uniform Ru distribution would result in a proper surface Ru concentration as well as more direct Ru-Ni interaction, accounting for better catalyst performance. Enriched surface Ru species hinders surface carbon deposition, but also declines overall activity and H₂/CO ratio, meanwhile likely enhances Ni oxidation to certain degree under the applied reaction conditions. Over the current (m%Ru-Ni)@SiO₂ catalyst, the formation of fibrous carbon species is suppressed, which accounts for good stability of catalyst within a TOS of 10 h.