Mechanically driven selective organic oxidation using MOF-coated piezoelectric SnSe nanosheets

Achieving high selectivity and activity in organic conversions through environmental-friendly catalytic approaches is crucial in green chemistry. In this study, we report a hybrid piezocatalyst composed of two-dimensional (2D) piezoelectric SnSe nanosheets loaded by amorphous UiO-66-NH₂ metal-organic frameworks (MOF). This SnSe/MOF nanocomposite catalyst exhibits exceptional efficiency for mechanically-driven selective organic oxidation, achieving a remarkable reaction rate of 604.3 μmol g⁻¹ h⁻¹ for oxidizing benzyl alcohol to benzaldehyde under ultrasonication vibration (90 W, 45 kHz), with a conversion ratio of ∼95.3 % in only 1.5 h and selectivity over 99 %. Combined experimental results and theoretical simulations elucidate that the interfacial chemical bonds formed between SnSe and MOF establish a charge flow “highway” for mechanically excited free carriers, while the MOF coating layer acts as a co-catalyst that lowers the reaction barrier for H₂O₂/•OH production, facilitating selective organic conversion reactions. Additionally, the MOF layer significantly enhances the hydrophilicity and stability of the 2D SnSe piezocatalysts in reaction solvents. This study demonstrates a simple, green, and efficient piezoelectrically-mediated mechanochemical method for selective synthesis of high-value-added organic chemicals.