Efficient Hydrogenation of CO 2 to Higher Alcohols over Cu–Zn–Fe Catalysts: The Role of ZnFe 2 O 4 Spinel Precursor

Spinel-structured metal oxides offer unique advantages in heterogeneous catalysis due to their structural stability, tunable electronic properties, and multimetal synergistic effects. Herein, we strategically integrated ZnFe2O4 spinel with a conventional CuFe-based catalyst (CuFeOx) to enhance the catalytic performance for CO2 hydrogenation to higher alcohols, achieving a higher alcohol selectivity of 28.9% over the CuZnFeOx catalyst. In the catalyst, ZnFe2O4 stably anchors CuO via strong interfacial adhesion (3.3 J/m2) to form a stable CuO–ZnFe2O4 interface structure that promotes Cu dispersion. And during the subsequent reduction process, this structure modulates the reducibility of Fe3+ via Cu–ZnFe2O4 synergy, thereby facilitating in situ formation of FeCx sites (FeCx content, 51.6 → 67.7%) in the reaction. Mechanistically, the precisely tuned Cu and FeCx dual-active centers effectively optimize the nondissociative and dissociative activation of CO, promoting C–C coupling for higher alcohol synthesis. Furthermore, oxygen-vacancy-rich ZnO provides additional CO2 adsorption sites (−1.46 eV) and synergistically stabilizes H2/CO species at Cu/Fe active centers. Ultimately, the CO2 conversion on the CuZnFeOx catalyst increases to 35.2%, and the space–time yield for higher alcohols reaches 125.1 mg·gcat–1·h–1, which is 4.4 times higher than that of the CuFeOx catalyst. This study establishes a catalyst design strategy that utilizes ZnFe2O4 spinel integration to regulate the final active structure for the optimized catalytic performance.