In situ decorated Pd NPs on chitosan-encapsulated Fe3O4/SiO2-NH2 as magnetic catalyst in Suzuki-Miyaura coupling and 4-nitrophenol reduction

• In situ fabricated of Pd nanoparticles on chitosan-encapsulated Fe 3 O 4 /SiO 2 -NH 2 nanoparticles. • The novel catalyst applied for Suzuki-Miyaura coupling and reduction of 4-nitrophenol. • The core-shell nanoparticle modified with chitosan highly stabilizes the exterior Pd NPs. • The catalyst can be reused several consecutive cycles. Chitosan is a linear polysaccharide and non-toxic bioactive polymer with a wide variety of applications due to its functional properties such as ease of modification, and biodegradability. In this study, a green protocol for in situ fabrication of ultrafine Pd nanoparticles on chitosan-encapsulated Fe 3 O 4 /SiO 2 -NH 2 nanoparticles, without the use of any toxic reducing agents, is described. The catalytic activity of Fe 3 O 4 /SiO 2 -NH 2 @CS/Pd nanocomposite was investigated through Suzuki-Miyaura coupling to synthesize biaryl derivatives, and reduction of 4-nitrophenol to 4-aminophenol. The core-shell nanoparticle modified with chitosan highly stabilizes the exterior Pd NPs. Leaching test was performed to assure heterogeneity of the catalyst. The magnetically retrievable catalyst was recycled up to eight times in both reactions without significant loss in its activity.