Exploiting Interfacial ZnO-Cu Nanocomposites in Metal–Organic Framework Derived Catalysts: Enhancement of Catalytic Activity for CO₂ Hydrogenation

The nanointerfaces of ZnO-Cu and the size of active nanoparticles (NPs) play crucial roles in the development process of CO2 hydrogenation. Herein, Zn-PBC80 with an unsaturated coordination Zn2+ center was constructed from Zn(NO3)2·6H2O and 3,5-bis(4′-carboxyl-phenyl) pyridine (H2PBC), serving as an anchoring site for supporting Cu2+ and a platform for encapsulating NPs. The different loading concentrations of Cu2+ and pyrolysis of the MOFs-based precursor vary the chemical environments of the catalysts, resulting in different distributed states and average sizes of active sites. Specifically, the pyrolysis of Zn-PBC80-Cu-1 with a concentration ratio of 1:1 facilitates the construction of an interfacial ZnO-Cu nanocomposite and smaller NP size. Among a series of CO2 catalysts, the resultant ZnO-Cu-1-700 exhibits the best catalytic performance with a satisfying CO2 conversion rate (16.5%), outstanding CO selectivity (100%), and promoting catalytic stability over 30 h. The best catalytic performance could be attributed to the more stable electronic structure of metallic Cu NPs and the generation of oxygen vacancies resulting from the unique ZnO-Cu nanointerfaces among the catalysts. This discrepancy in catalytic performance indicates that the active nanointerfaces affects the electronic structure of active centers, providing valuable insight into the design of efficient catalysts for CO2 reduction.