Transition metal oxide manipulating ZrO₂-based non-precious metal catalysts for enhanced CO₂-mediated oxidative dehydrogenation of propane

BACKGROUND: Developing highly stable and cost-effective catalysts for CO₂-mediated oxidative dehydrogenation of propane (CO₂-ODP) is critical to advancing sustainable propylene production. While ZrO₂-based supports offer promising thermal stability and tunable acid–base properties, integrating transition metal oxides (TMO_x) as active sites to optimize CO₂ activation and propane conversion remains underexplored. RESULTS: Here, we systematically design a series of non-precious metal TMO_x/ZrO₂ catalysts (TM = Cr, Fe, Co, Ni, Cu, Zn) via a coprecipitation–gel method to uncover structure–activity relationships. Among them, CrO_x/ZrO₂ emerges as the optimal candidate, achieving notable C₃H₈/CO₂ conversions of 46.24%/38.27% and 86.49%/27.03% C₃H₆ selectivity/yield at 600 °C. Characterization reveals that the coexistence of Cr³⁺/Cr⁴⁺ species (XPS) and mixed-phase Cr₂O₃/CrO₂ (XRD/Raman) creates abundant oxygen vacancies and enhances CO₂ adsorption (TPD), while HRTEM/EDX confirms uniform CrO_x dispersion on ZrO₂. Further optimizing the Cr/Zr ratio to 1:1 maximizes active site exposure while preventing excessive aggregation, thereby balancing redox activity and structural stability. CONCLUSIONS: This work elucidates how tailored TMO_x/ZrO₂ interfaces leverage synergistic electronic and geometric effects to drive CO₂-ODP efficiency, offering a blueprint for designing high-performance non-precious metal catalysts for alkane valorization.