In-Situ and green photosynthesis of PVP-stabilized palladium nanoparticles as efficient catalysts for the reduction of 4-nitrophenol

Here, we report for the first time in-situ photogeneration of poly (N-vinyl-2-pyrrolidone) (PVP) stabilized palladium (0) nanoparticles (PdNPs) and their catalytic activity in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). PdNPs with an average particle size of 9 ± 3 nm were synthesized from the photoreduction of Pd2+ by electron donor radicals generated from Irgacure-2959 and were stabilized by concomitantly formed PVP. Thus obtained PVP-stabilized PdNPs were stable in solution (water, ethanol, and diethyl ether) and could be isolated as solid materials by centrifugation. Wide-angle X-ray diffraction (WAXD) analysis revealed the formation of a face-centered cubic Pd crystal structure with dominant lattice plane {1 1 1}, as confirmed by high-resolution transmission electron microscopy (TEM) analysis. TEM analysis also confirmed the stabilization of PdNPs with PVP. This behavior was also evidenced by FTIR analysis through shift of the C=O stretching band. Notably, the aggregation of the PdNPs was observed in the absence of PVP. PdNPs prepared by this methodology exhibited highly efficient catalytic activity in the reduction of 4-NP as investigated using spectral analysis.