The solvent-free and aerobic oxidation of benzyl alcohol catalyzed by Pd supported on carbon nitride/CeO2 composites

Abstract

The selective oxidation of benzyl alcohol using molecular oxygen is a sustainable strategy for the green synthesis of benzaldehyde, and an important research topic is developing heterogeneous catalysts that can afford high activity, especially under solvent-free and aerobic conditions. In this work, Pd catalysts supported on carbon nitride–ceria composites were prepared through a simple wet impregnation method, and they were then analyzed in detail using various characterization techniques. The combination of carbon nitride and ceria can not only steadily anchor Pd but it can also provide more active lattice oxygen. The catalytic performance of Pd/carbon nitride/CeO₂ (Pd/CN/CeO₂) was evaluated during the solvent-free and aerobic oxidation of benzyl alcohol. Under the same reaction conditions, Pd/CN/CeO₂ demonstrated superior activity to both Pd/eg-C₃N₄ and Pd/CeO₂, and the maximum yield of benzaldehyde achieved when using Pd/CN-1.0/CeO₂ was 77%. Furthermore, the catalyst can be reused six times without any significant loss of catalytic activity, and it also exhibited good generality, allowing reactions with various substrates.