Nano-Ni/Cu decorated iron oxide for catalytic reduction of 4-nitrophenol

This study utilized fast, affordable, and simple impregnation methods to produce a more affordable, highly active, and recyclable Cu and Ni magnetic nanocatalyst for the removal of 4-nitrophenol (4-NP) from wastewater. The core-shell synthesis methods used capture the magnetic capability at the center via a superparamagnetic iron oxide nanoparticle (SPION) core while utilizing the catalytically active Cu and Ni atoms on its surface. Monometallic coated Ni and Cu SPIONs (SPION@Ni) and SPION@Cu) as well as bimetallic Cu/Ni coated SPIONs (SPION@Ni/Cu) ranging between 15 and 21 nm were evaluated for the reduction of 4-NP to 4-aminophenol (4-AMP) in the presence of excess NaBH4 as reducing agent. The Ultraviolet–visible (UV–Vis) spectroscopy method was utilized to monitor the catalytic kinetic reaction. The assessed nanoparticles demonstrated enhanced activity in the progression from SPION@Ni to SPION@Cu, with SPION@Ni/Cu nanoparticles proving to be the most efficient, particularly with AL18 (SPION@Ni/Cu (1(SPION):0.2(M2+)) achieving a kapp of 0.103 s−1. In addition, AL18 was easily separated via magnetic decantation and successfully reused for up to ten consecutive reactions.