Imine-coordination-mediated synthesis of Mo2N-ZnO/CNP catalyst from MOFs@Polyoxometalates for enhanced CO2 cycloaddition with epoxides

Using an imine-coordination-mediated PSM-pyrolysis strategy to fabricate Mo 2 N-ZnO based catalyst (MZ/CNP- icm ). • The MZ/CNP- icm catalyst was applied for CO 2 cycloaddition reaction. • High activity ascribed to more Mo 2 N with synergistic interaction between Mo 2 N and ZnO. The cycloaddition of CO 2 with epoxides into cyclic carbonates represents an atom-economical and sustainable pathway for carbon utilization, yet it requires catalysts capable of synergistically activating both substrates. Herein, a heterostructured Mo 2 N–ZnO catalyst embedded in N,P-doped carbon (MZ/CNP- icm ) is constructed via an imine-coordination-mediated post-synthetic modification and pyrolysis strategy using a 2D imine-rich Zn-MOF (Zn- hmta ) and phosphomolybdic acid (PMo 12 ). The imine coordination enables molecular-level anchoring of Mo species and creates a nitrogen-rich microenvironment, which directs the phase evolution toward Mo 2 N rather than inactive MoO 3 during pyrolysis. As a result, well-defined Mo 2 N-ZnO heterointerfaces and a defect-rich carbon matrix are formed. Under mild conditions (75 °C, 1 MPa CO 2 ), the catalyst achieves nearly 100% conversion and selectivity, together with a significantly enhanced turnover frequency compared to control samples. Mechanistic studies combining in-situ DRIFTS and 1 H NMR reveal that Zn 2+ sites activate epoxides while Mo 2 N activates CO 2 , and the heterointerface enables efficient coupling of intermediates. The catalytic enhancement originates from the synergistic interplay between interfacial electron transfer and defect-rich active sites. This work provides a general strategy for regulating phase evolution and interfacial structure in MOF-derived catalysts for efficient CO 2 conversion. Download: Download high-res image (198KB) Download: Download full-size image