ZnO/ZnCr2O4 biphasic catalysts with engineered interface for promoting isobutanol synthesis during syngas conversion

Due to the complicated component of ZnCr oxides, the function of the active phases remains controversy, limiting its improvement of catalytic performance for converting syngas to higher alcohols. Herein, a series of ZnCr catalysts with tunable ZnO/ZnCr 2 O 4 molar ratios were fabricated via ball milling of the two individual oxides. Within the ZnO:ZnCr 2 O 4 range of 1:1 to 0.5:1, both CO conversion (18.5%) and isobutanol selectivity (29.0%) were significantly enhanced, while the water‑gas shift reaction and hydrocarbon formation were effectively suppressed. This improved performance originated from synergistic interface effects as revealed by the systematic characterization (XPS, CO‑TPD, and in situ DRIFTS etc.). Lattice distortion and electronic interaction at the interface induced the producing of octahedrally coordinated Zn 2+ sites on ZnCr 2 O 4 , strengthening CO adsorption, meanwhile, ZnO promoted interface hydrogen migration and hydroxyl cycling, steering the CHO* intermediate formation and facilitating C–C coupling. Furthermore, the electron‑rich lattice oxygen at the interface, with moderate basicity, served as active sites for β addition reaction of C 2 intermediate and carbon‑chain growth. These findings clarify the critical role of dual‑phase interface structure in regulating the reaction pathway during syngas conversion, providing a new strategy for the design of high‑performance catalysts for isobutanol synthesis.