Efficient heterogeneous conversion of CO2 into quinazolinones catalyzed by yolk-shell Pd nanocubes@ZIF-8

In recent years, the direct utilization of CO2 as renewable C1 source to synthesize high-value-added products is increasingly attractive. Among various methods, the reaction of CO2, 2-haloanilines and isocyanides is a promising route for CO2 conversion, because the resultant products quinazolinones are important motifs in many bioactive drug intermediates. However, high-cost homogeneous noble metal catalysts based on Pd salts are often employed in this reaction, which greatly limit its industrial production from the point of production cost and catalyst recovery. Hence, developing suitable recyclable catalysts for efficient conversion of this reaction is highly desirable but still challenging. Herein, we successfully utilized a sacrificial template strategy to encapsulate Pd nanocubes (NCs) into ZIF-8. The obtained Pd NCs@ZIF-8 possesses a yolk-shell structure with highly dispersed Pd NCs as cores and porous ZIF-8 as shell. Such structure features can enrich CO2 and reactants to facilitate the accessibility of Pd NCs active sites. As a result, the Pd NCs@ZIF-8 can effectively catalyze the conversion of CO2 with isocyanides and 2-iodoanilines, which can be recycled at least five times without losing catalytic activity.