Synthesis of Highly Active Pd Nanoparticles Supported Iron Oxide Catalyst for Selective Hydrogenation and Cross‐Coupling Reactions in Aqueous Medium

Post synthetic approach was successfully employed for the synthesis of Pd supported iron oxide (Pd‐Fe 2 O 3 TA ) catalyst using polyvinylpyrrolidone as capping agent and triethanolamine as reducing agent. Performance of Pd‐Fe 2 O 3 TA catalyst was investigated for selective hydrogenation of nitro compounds and Suzuki coupling reactions. Prepared catalyst exhibited excellent yield of corresponding substituted amines and biphenyls, under optimized reaction conditions. Different analytical techniques such as BET‐surface area measurements, XRD, ICP‐AES, SEM, TEM, XPS, TPR, FT‐IR, RAMAN, UV‐Vis and EXAFS analysis were employed to characterize the catalyst. Average particle size of palladium nanoparticles (NPs) was found to be ∼5.2 nm supported on 60–120 nm size of iron oxide nanocrystals. Various reaction parameters such as time, temperature, solvents, active metal loading, base and different substituent were investigated in detail. Different catalysts were also prepared and compared their activity with that of Pd‐Fe 2 O 3 TA catalyst. Experimental observations revealed that size of palladium NPs and metal‐support interaction favoured the superior activity of Pd‐Fe 2 O 3 TA catalyst compared to other catalysts. Stability of Pd‐Fe 2 O 3 TA catalyst was confirmed by its recyclability tests indicated true heterogeneous nature of catalyst.