Selective phase exposure induces Ni-Ce interfacial redox reconstruction for CO2 activation

초록

Efficient catalytic activation of CO2 remains a central challenge in heterogeneous catalysis because of the thermodynamic stability and kinetic inertness of the CO2 molecule. Metal–oxide interfaces are widely recognized as key catalytic environments where cooperative redox processes enable CO2 dissociation and catalyst regeneration, yet their catalytic functionality is often limited by incomplete exposure of metal–oxide interfacial sites. Here we report a selective phase exposure strategy to reconstruct redox-active Ni–Ce interfacial environments in Ni–Ce–Al catalysts. Ni–Ce–Al oxide microspheres were synthesized by spray pyrolysis followed by controlled alkaline leaching. This treatment selectively removes γ-Al2O3 while preserving NiAl2O4 and CeO2 phases, exposing buried Ni–Ce interfacial domains and suppressing CeAlO3 formation. As a result, CeO2 species are stabilized adjacent to Ni sites, generating defect-rich and redox-active oxygen environments with enhanced oxygen mobility at the metal–oxide interface. Moderate leaching maximizes the exposure of metallic Ni and defect-rich CeO2 at Ni–Ce interfaces, whereas excessive leaching disrupts the reconstructed interfacial redox environment and decreases the contribution of mobile defect-related oxygen species. Operando DRIFTS measurements reveal stabilized CO2-derived intermediates associated with the reconstructed interface. The catalysts were evaluated for the synergistic coupling of dry reforming of methane (CH4 + CO2 ↔ 2CO + 2H2) and the reverse water–gas shift reaction (CO2 + H2 → CO + H2O). The optimally leached catalyst achieves CH4 and CO2 conversions of 90.2% and 55.1%, respectively, and maintains stable performance over 100 h under CO2-rich SCDR conditions, highlighting the role of Ni–Ce interfacial domains in redox-assisted CO2 activation.

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