MOF-derived Zr-Ce solid solutions with engineered oxygen vacancies for efficient direct synthesis of dimethyl carbonate from CO2

Direct synthesis of dimethyl carbonate (DMC) from CO 2 is a sustainable carbon utilization route but suffers from thermodynamic limitations and rapid catalyst deactivation. Herein, we report a scalable MOF-derived strategy to construct porous Zr x Ce 1-x O 2-δ solid solution catalysts with tunable oxygen vacancies (O v ) by precisely controlling calcination conditions. Although calcination at 700 °C decreased the specific surface area, it optimized Ce 3+ /(Ce 4+ +Zr 4+ ) synergy and O v density, thereby enhancing CO 2 activation and surface acid–base properties. Thermodynamic analysis underscores the critical role of dehydrating agents in overcoming equilibrium constraints. Furthermore, DFT calculations reveal that O v lowers the rate-limiting *CH 3 OCOO dissociation barrier by 0.69 eV, while competitive adsorption between the dehydrating agent (2-cyanopyridine) and its product (pyridine-2-carboxamide) on active sites drives catalyst deactivation. Under optimized conditions (700 °C calcination; 140 °C, 4 MPa), Zr 0.05 Ce 0.95 O 2-δ achieved an exceptional DMC formation rate of 261.99 mmol·g −1 ·h −1 with 97.71% selectivity. This work provides new insights into defect engineering and deactivation mechanisms, establishing a rational design strategy for efficient CO 2 -to-chemical conversion.