Bimetallic Nanoparticles Anchored on Core–Shell Support as an Easily Recoverable and Reusable Catalytic System for Efficient Nitroarene Reduction

[Image: see text] We report an easily recoverable and reusable versatile magnetic catalyst (Fe(3)O(4)@CS_AgNi, where CS = chitosan) for organic reduction reactions. The catalytic system is prepared by dispersing AgNi bimetallic nanoparticles on the magnetite core–shell (Fe(3)O(4)@CS). The as-synthesized catalyst has been characterized by spectroscopic techniques, such as IR, UV–vis, and X-ray photoelectron spectroscopy (XPS), and analytical tools, such as thermogravimetric analysis, powder X-ray diffraction, Brunauer–Emmett–Teller adsorption, FEG–scanning electron microscopy, high-resolution transmission electron microscopy (HR-TEM), inductively coupled plasma-atomic emission spectroscopy, and magnetic measurements. HR-TEM studies indicate the core–shell structure of Fe(3)O(4)@CS and confirm the presence of AgNi nanoparticles on the surface of Fe(3)O(4)@CS spheres. IR spectral and XPS studies lend evidence for the occurrence of a strong chemical interaction between the amino groups of CS and AgNi nanoparticles. The nano-catalyst Fe(3)O(4)@CS_AgNi rapidly reduces p-nitrophenol to p-aminophenol using NaBH(4) as the reductant within a few minutes under ambient conditions (as monitored by UV–visible spectroscopy). The utility of this catalytic system has also been extended to the reduction of other nitroarenes. A strong interaction between Fe(3)O(4)@CS and AgNi nanoparticles impedes the leaching of AgNi nanoparticles from the core–shell support, leading to excellent reusability of the catalyst.