Designing of Ultrafine PdNPs Immobilized Pyridinic‐ <i>N</i> Doped Carbon and Evaluation of its Catalytic Potential for Konevenagel Condensation, Synthesis of 4 <i>H‐</i> pyran Derivatives and Nitroreduction

Abstract

Abstract We report the desiging of ultrafine Pd‐based nanocatalyst containing N ‐doped carbon structure (Pd@NC). The material was prepared by direct dehydration at 120 °C followed by mixing and heating with a dopant (ammonium oxalate) at 150 °C in a furnace. The Pd@NC nanocatalyst containing electron‐rich pyridinic‐ N doped carbon structure, was thoroughly characterized by various techniques namely SEM, EDX, TEM, FTIR, ICP‐AES, XRD, XPS, TGA and Raman spectroscopy. The utility of the Pd@NC nanocatalyst was explored for base‐free Knoevenagel condensation and 4 H ‐pyran derivatives and also in the reduction of nitroarenes under mild and greener conditions. Further, the optical property was explored using photoluminescence spectroscopy and band gap was also calculated. The heterogeneous nature and stability of the catalyst facilitated by its ease of separation for long‐term performance and recycling studies showed that catalyst was robust and remained active upto six recycling experiments. Also, the leaching of metal was confirmed by ICP‐AES. The superiority of the catalyst was attributed to the metal support interaction (MSI) between metallic palladium and pyridinic‐ N doped carbon to acquire excellent catalytic activity and changing the reducing nature of NaBH 4 towards nitro functionality. The MSI between pyridinic‐ N dopant on the carbon structure and PdNPs produces highly active sites for catalytic performance under mild conditions.