CeO2-doped NiAlOx catalysts boost CO2 methanation for Power-to-Gas.
TUM.PtX News |
The team prepared LDH-derived NiAlOx mixed oxides by coprecipitation and doped them with CeO2 at Ce/Ni ratios of 0.05, 0.1, and 0.3, benchmarking against undoped NiAlOx and additional reference materials. Structural analysis indicates a two-phase system (NiAlOx + CeO2) rather than a single mixed oxide, while Ce addition leads to smaller Ni particles after reduction.
Quasi in situ XPS demonstrates reversible reduction/oxidation cycles and shows that CeO2 can be partially reduced to generate Ce3+/Ce4+pairs (oxygen vacancies). Importantly, CeO2 reduction (and thus vacancy formation) is only feasible in the presence of Ni, which dissociates H2 and enables hydrogen spillover to CeO2. CO2-TPD confirms stronger and increased CO2 adsorption with CeO2 addition, consistent with vacancy-assisted CO2 binding. Catalytic tests at differential conditions reveal up to three-fold higher TOFs and CH4 weight-time yields compared to undoped NiAlOx, with a clear optimum at Ce/Ni = 0.1. At this optimum, the catalyst reaches TOF = 0.46 s⁻¹ and WTY = 75.04 μmol s⁻¹ gcat⁻¹ under the reported kinetic regime, indicating substantially improved intrinsic activity. At too high Ce content (Ce/Ni ≈ 0.3), CO formation increases, highlighting the need to balance Ni (H2 activation) and CeO2 (CO2 activation) to avoid byproducts.
[1] H. Plendl, et al. “Synthesis, characterization and activity of CeO2-doped coprecipitated NiAlOx catalysts for CO2 methanation.” Applied Catalysis A, General 711 (2026) 120728.