Mechanochemical construction of MgO–Co–TiO2 dual-function materials for intermediate-temperature integrated CO2 capture and methanation

Abstract

This study reports a ternary dual-function material (DFM) prepared via a facile mechanochemical strategy for integrated in situ CO2 capture and methanation at 250 °C, and reveals the role of mechanical ball milling in regulating morphology and optimizing the catalytic reaction pathway. MgO–Co–TiO2 composite was directly constructed via mechanochemical ball milling at 800 rpm, without additional loading or calcination steps. The ball milling process promotes homogeneous mixing of the components and the formation of three-phase interfaces. At 250 °C, the system achieved an H2 conversion of 68.52% under mechanical vibration, which was significantly higher than that under static conditions, while the mechanical energy consumption accounted for less than 5% of the total energy input. Comprehensive characterization results indicate that mechanochemical ball milling generates abundant surface oxygen defects and enhances interfacial coupling among the components, thereby facilitating the hydrogenation of captured carbonate intermediates. Regarding cyclic stability, , the cyclic stability of the system was significantly improved by implementing a strategy to ensure an excess carbon capacity supply, with H2 conversion remaining stable above 40% over 13 consecutive cycles. The findings indicate that integrating mechanochemical treatment with dual-function materials provides a workable route for intermediate-temperature CO2 capture and methanation, without relying on high-temperature preparation steps.