Selective Oxidation of Methane by Piezoelectric Catalysis Under Mild Conditions

Selective partial oxidation of methane (CH₄) at room temperature is a challenge in catalytic chemistry. Herein, we report a piezoelectric-responsive metal-organic framework (MOF), Cu-UiO-66-NH₂, as an efficient catalyst to convert CH₄ to C1 products selectively. In flow reactors under ultrasonic activation, this catalyst achieves a methanol production rate of 175.1 µmol·g⁻¹·h⁻¹ with 82% selectivity. Parallel experiments in batch reactors demonstrate yields of CO (297.4 µmol·g⁻¹·h⁻¹) and H₂ (140.6 µmol·g⁻¹·h⁻¹). In the piezocatalytic process, in situ generated H₂O₂ was decomposed to produce hydroxyl radical (·OH) to active C─H of CH₄. Cu(II)-O· species could formed from the decomposition of Cu(II)-OOH intermediate to selective partial oxidation CH₄ but not to form CO₂. This MOF-based catalyst design integrated piezocatalysis and mimics enzymatic catalysis, supplying new insight to develop robust catalysts for the industrial conversion of methane with low concentration (<10%).