Abstract
The hydrogenation of carbon dioxide to formic acid has attracted considerable interest for carbon utilization and hydrogen storage. Metal-organic frameworks (MOFs), featuring open coordination sites and tunable pore structures, offer unique advantages for heterogeneous catalysis. Herein, we report the catalytic performance of a series of defect-engineered Ru-MOF catalysts for the hydrogenation of CO(2) to formate. The catalysts were synthesized by partially substituting the organic linker with 3,5-pyridinedicarboxylic acid (PYDC) to introduce controllable defect sites. Among the series, the defective Ru-MOF prepared with an optimal PYDC ratio of 30% used during synthesis (D3-Ru-MOF) exhibits enhanced catalytic performance for CO(2) hydrogenation to formate compared with its nondefective counterpart. After hydrogen pretreatment, D3-Ru-MOF achieves a turnover number (TON) of 1258 at 120 °C over 24 h while maintaining good structural stability. A clear structure-activity relationship was observed with catalytic performance dependent on defect density within the framework. This study demonstrates the effectiveness of defect-engineering in Ru-MOFs for improving CO(2) hydrogenation performance.