Metallomicelle templated transition metal nanostructures: synthesis, characterization, DFT study and catalytic activity

Abstract

A simple and versatile protocol to achieve surface-modified catalytically efficient nanoparticles employing metallosurfactants as excellent scaffolds has been reported. The metallomicelle act as an efficient single precursor template for metal nanostructure fabrication displaying a strong interrelationship between their size and shape. Preferred binding of nanostructures to a capping agent (amine or carboxylate) alters the activity and dispersibility (aqueous or non-aqueous), resulting in various sizes (sub nm–15 nm) and morphologies (spherical, capsule like). The ligand–nanoparticle surface interaction reveals that acetate binds more effectively to Fe and Zn surfaces while dodecylamine works well for Co, Ni and Cu, corroborated by both DFT and experimental FTIR results. Ab initio studies reveal higher binding energy for Fe which leads to excellent stabilization of particles in the quantum domain, whereas the lower interaction between Zn and the acetate ligand results in much larger sized particles. The nanostructures synthesized possess excellent catalytic activity with the reaction performance following the trend Co > Ni ≈ Cu > Zn > Fe, implying that the conversion rate increases with a decrease in NP size, with the exception of Fe. This study points out a new direction in nanomaterial synthesis establishing correlation between the structure of the metallomicelles and morphology of the metal oxide nanostructures formed.