Catalytic epoxidation of limonene and air with high performance by zirconium cobalt bimetallic MOF lamellar materials

In this paper, the bimetallic ZrCo-MOF materials were synthesized via static hydrothermal synthesis with the introduction of the more acidic metal Zr. The morphological and physicochemical studies demonstrated a successful fabrication of the targeted material, and the catalyst has a three-dimensional hexagonal block lamellar structure. The catalytic performance of the synthesized catalyst was investigated in the limonene epoxidation with air as oxidant without any initiator or co-reducer. Because of the synergistic effect of electron transfer between Zr and Co, the bimetallic ZrCo-MOF catalyst showed limonene conversion significantly higher compared to those of Zr-MOF and Co-MOF. The best catalytic activity of Zr0.7Co3 static -MOF-BTC-S-H-170-24 h was demonstrated, with limonene conversion up to 96.4% and >99% selectivity of the epoxidation products. In addition, the Zr0.7Co3-MOF-BTC-S-H-170-24 h catalyst could be recycled six times without significant reduction of the catalytic activity, indicating the stability of the bimetallic catalyst material under mild reaction conditions. This study provided a foreseeable possibility for obtaining universal synergistic catalysts in industrial heterogeneous catalysis.