<p>Harnessing CO₂ as a feedstock for producing value-added materials is recognized as a promising approach in sustainable chemistry. The significance of CO₂ in synthesizing propylene carbonate (PC) through its coupling with propylene oxide (PO) is underscored by the diverse industrial applications of PC. To develop an effective Co-based spinel catalyst for PC production, spinel-type mixed metal oxides, MCo₂O₄ (M = Mg, Cu, Ni, Zn), were synthesized via a facile coprecipitation process. The high purity and well-defined cubic spinel structures of the materials were confirmed through X-ray diffraction (XRD) analysis. The catalytic performance of these oxides was evaluated for solvent-free PC production, with notable potential exhibited by MgCo₂O₄. The catalytic activity was enhanced by the development of a heterostructure catalyst of MgO/MgCo₂O₄. Various characterization techniques, including XRD, FTIR, XPS, BET, SEM, TEM, EDX, and TGA, were employed to assess the purity and structural features of the MgO/MgCo₂O₄ composite. Catalytic tests were conducted under mild conditions, with variations in cocatalyst type, reaction temperature, and CO₂ pressure systematically introduced. The MgO/MgCo₂O₄ composite, with tetraethylammonium bromide (TEABr) used as a cocatalyst, achieved a PO conversion of 95% and a PC selectivity of 99% at 75&#xa0;°C and 50 psi CO₂ over six hours. The enhanced activity of MgCo₂O₄, supported by MgO, was linked to altered acid–base properties and improved particle dispersion. Additionally, the MgO/MgCo₂O₄ heterostructure catalyst exhibited good stability and could be recycled multiple times for PC synthesis without significant loss of performance.</p> Graphical Abstract <p>Graphical abstract of the preparation method and catalytic process.</p> <p></p>