Rational screening of milling parameters for Ru–Na/Al2O3 dual-function materials for integrated CO2 capture and methanation†

The interest in the use of mechanochemistry as a green alternative to conventional solution-based synthesis methods has been steadily growing in recent years. Recently, Dual-Function Materials (DFMs) have been explored for the preparation of multicomponent systems which combine a sorbent and a catalytic phase co-supported on a support oxide for the capture of CO₂ from flue gases and its subsequent conversion into added-value products when exposed to H₂ (or CH₄) in a chemical-looping-type reaction. However, the complexity of setting the right milling parameters, which are interconnected and strongly dependent on the precursor materials, is exacerbated in the multi-component system. In this work, we address this issue by employing a Design of Experiments (DoE) statistical approach for the screening of the most relevant milling parameters for the synthesis of Ru–Na/Al₂O₃ DFMs for integrated CO₂ capture and methanation (ICCU-MET). The milling intensity and the organic precursors proved to be the key factors positively affecting the DFMs' capture capacity and CH₄ conversion, respectively.