Suppressing cyclic deactivation of magnesium-calcium dual-functional materials via dispersed metal-carbonate interfaces for integrated CO2 capture and conversion

Abstract

The integrated CO₂ capture and utilization employs chemical looping approach for suppressing the equilibrium limitations of traditional gas-solid catalytic reactions, enabling efficient conversion of dilute CO₂ into high-value fuels with minimal energy consumption. However, the diminishing cyclic activity of dual-functional materials poses significant challenges to their industrial application. Herein, we tailored a series of magnesium-calcium materials, the influence of coordinated metals on the cyclic performance were quantitatively investigated. Notably, Fe₂Ni₂Ce₂Mg₅Ca₂₀CO₃ achieves a cumulative CO yield of 121.0 mmol/g over 15 cycles at 650°C, with a maximum CO yield of 8.3 mmol/g per cycle and 99.0% CO selectivity, and its CO₂ capture capacity remains stable at 10.6 mmol/g over 37 adsorption/desorption cycles. Experimental results indicate that lattice phase separation is a fundamental mechanism underlying the decline in cyclic activity. The strategic incorporation of transition metal intermediates promotes the formation of dispersed metal-carbonate interfaces, providing surface hydrogenation sites and accelerating the lattice decomposition and reconstruction of CO₃* within a dispersed lattice. This modification mitigates the adsorption/catalytic lattice phase separation, boosts metal migration and deoxygenation activity for cyclic nanoparticle construction. The findings offer valuable strategies for designing highly efficient and stable DFMs in CO₂ capture and utilization.