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.