Tailoring component interactions over Ca-Fe-Ni bifunctional materials for efficient integrated CO2 capture and conversion

Abstract

Unveiling the component interactions over bifunctional materials remains a challenge to achieve efficient integrated CO₂ capture and conversion. Herein, Ca-Fe-Ni bifunctional materials with varying catalyst and oxygen carrier loadings are synthesized, examined and characterized to reveal the influence of component interactions on the material structure, cyclic reactivity, carbon deposit and reaction mechanism. Ca₈₀Fe₀Ni₁₅Zr₅ exhibits the largest syngas space time yield (67.9 mmol_CO·s⁻¹·kg_Fe&Ni⁻¹ and 69.8 mmol_H2·s⁻¹·kg_Fe&Ni⁻¹) with a limited deactivation. Ni weakens the interaction between calcium and iron oxides through facilitating the reduction of dicalcium ferrite whilst iron oxide decreases the carbon formation via forming Ni-Fe alloy and providing lattice oxygen. The component interactions result in a slight effect on the identified H-spillover assisted mechanism for Ca-Fe-Ni bifunctional materials but leads to an impact on the phase evolutions, side reactions and carbon deposit. This study provides a new strategy for rational designing bifunctional materials with high activity and stability.