Specific nanostructures of CeO₂ and GDC supports turn iridium to an efficient Power-to-Gas catalyst for the selective hydrogenation of CO2 to methane

Thermo-catalytic CO₂ hydrogenation to methane (Sabatier reaction) represents a key pathway for mitigating carbon emissions and enabling renewable hydrogen storage within the Power-to-Gas (P2G) energy model. When coupled with green hydrogen produced via renewable-powered water electrolysis, the process provides a promising route for safe hydrogen storage and transport, overcoming limitations associated with pure hydrogen handling. Depending on the catalyst used, the CO2 hydrogenation can selectively lead to the formation of methane (CH4), known as Sabatier reaction: CO2 + 4H2 ⇌ CH4 + 2H2O (1). The catalytic performance of CO₂ methanation strongly depends on the nature of the active metal and, critically, on metal–support interactions. Although several non-precious (Ni, Fe, Co) and noble metals (Ru, Rh, Pt) are recognized as efficient methanation catalysts, their activity and selectivity are highly influenced by the support properties and structure.
In the present work, the possibility of transforming iridium —generally considered an inefficient methanation catalyst— into a highly active and selective system was investigated through its dispersion on CeO₂ and GDC (Ce₀.₉Gd₀.₁O₂) supports with controlled nanostructures.