Anticoking Effect of Eu³⁺ Doping of the Ru/Ceria Catalyst in the MSR Reaction for Hydrogen Generation

The positive effect of Eu³⁺ doping on the stability of the Ru/ceria catalyst during the methane steam reforming (MSR) reaction, which was used for H₂ production, was observed. The effect is attributed to a significant inhibition of coking-induced deactivation of the catalyst by Eu doping, which we explain by three hypotheses. The first one is an increase in basicity with Eu doping, which inhibits carbon deposition on the working catalyst during the MSR reaction. The second one is that Eu addition introduces strain into the ceria lattice, which could facilitate oxygen diffusion and, as a consequence, prevents catalyst's coking. The third one is related to the presence of an additional high-temperature pathway for supplying lattice oxygen based on Eu³⁺ → Eu²⁺ reduction on the surface of the Eu-doped ceria support.