Entropy engineering enables synthesis of a perovskite-derived Ni–Co–Cu/La2O3–OV catalyst for efficient and stable CO2-to-CO conversion

Abstract

The challenge in designing efficient reverse water–gas shift (RWGS) catalysts necessitates high CO selectivity and CO₂ conversion while suppressing CH₄ formation and ensuring thermal stability. In this study, entropy engineering was proposed to successfully synthesize the medium entropy encapsulated crystalline oxide catalyst La₄(NiCoAlCu)O_x (MEO). The entropy-driven delayed diffusion promotes the formation of the Ni–Co–Cu alloy phase during the reduction process, while the simultaneous formation of the La₂O₃ support improves the dispersion of the active metal. It combined with the physical confinement effect of the hierarchical porosity structure, effectively stabilizing the Ni/Co/Cu nanoparticles against high temperature agglomeration. Entropy-induced lattice distortion generated abundant oxygen vacancies, providing strong adsorption sites for CO₂ and promoting H₂ dissociation into active H* species. These synergistic effects created a tripartite active configuration (“alloy–oxide interface–oxygen vacancies”) within MEO, enabling an “efficient adsorption–activation–conversion” pathway. Consequently, MEO achieved outstanding catalytic performance and high thermal stability at 550 °C, maintaining ≥95% CO selectivity over 1000 hours. In contrast, enthalpy-dominated La₅(NiCoAlCuZr)O_x (Zr-MEO) suffered from significantly reduced activity due to multiphase segregation and oxygen vacancy scarcity. This work elucidates entropy engineering's pivotal role in stabilizing the catalyst structure and modulating interfacial activity, proposing an “entropy-driven structural engineering” strategy for designing durable, highly active, and selective high-temperature CO₂ hydrogenation catalysts.