Green synthesis of palladium nanoparticles mediated by Acer L. leaves as reducing agent, stabilizer, and carrier for Suzuki reaction

Abstract

Plant fiber‐supported palladium nanocatalysts (Pdx/FAL) with high catalytic activity and good stability were synthesized by one‐pot method using Na2PdCl4 as palladium source, Acer L. leaves as reducing agent, stabilizer, and carrier without adding chemical reducing agents or stabilizers. The as‐prepared catalysts were characterized by XRD, FT‐IR, SEM, TEM, and so forth. During the preparation process, the extraction of organic matter from Acer L. leaves, the reduction and stabilization of Pd2+, and the loading of palladium nanoparticles (PdNPs) were carried out simultaneously, which greatly simplified the preparation steps and reduced the cost. Oxygen‐ and nitrogen‐containing groups in the Acer L. leaf extract preferentially formed complexes with Pd2+, and then, the polyphenols reduced Pd2+ to Pd0, which ensured that PdNPs with small particle sizes were formed and embedded in porous plant fibers (extraction residue of Acer L. leaves) with oxygen‐containing groups, thereby improving the catalytic activity and stability of the catalyst. The characterization results showed that the prepared PdNPs with a face‐centered cubic structure were uniformly distributed on the support, and the average particle size was 3.08 nm. The Suzuki coupling reaction of 4‐bromonitrobenzene and phenylboronic acid by the prepared catalysts at 40°C showed that the reaction yield could reach 97.72%, and the TOF could reach 3,240.6 h−1, exhibiting high catalytic performance. The reaction of 4‐bromotoluene with phenylboronic acid gave a yield of 98.58%, which remained above 90% after seven repetitions. This article provided a simple, high‐performance, and eco‐friendly synthesis idea for nanopalladium catalysts.