Dual confinement of copper species on Al-doped Fe3O4 spinel catalyst for efficient water-gas shift reaction

Cu-based water–gas shift catalysts suffer severe sintering due to Cu oxidation state changes and particle aggregation. To address this challenge, Al-doped Fe 3 O 4 spinel supports were constructed. The optimized Cu/Fe 3 O 4 -A 3 catalyst with an Al/Fe molar ratio of 3:3 achieved near-theoretical CO conversion (98.24% vs. the thermodynamic equilibrium of 98.50%) and maintained >97% conversion over 100 h. HAADF-TEM and in-situ XRD analysis revealed that CuFeAlO 4 spinel cages suppress Cu migration (Δd 311  < 0.02 Å at 300 °C), while the formation of Cu–O–Al covalent bonding strengthens metal-support interaction and inhibits Ostwald ripening. Combined DFT and ab initio molecular dynamics simulations further demonstrate that Cu–O–Al covalent bonding enhances the anchoring of Cu species, and increases the migration energy barrier to 1.37 eV—approximately 1.5 times higher than that of conventional Cu/Fe 3 O 4 . This work establishes a paradigm for sintering-resistant catalyst design via spinel-interface engineering.