Electrochemical Nucleation and Growth of Pd-Co Alloy Nanoparticles from the Reline Deep Eutectic Solvent

Abstract

For the first time, electrochemical formation of Pd-Co alloy nanoparticles (PdCoNPs) on a glassy carbon electrode (GCE) from their metallic precursors dissolved in the reline deep eutectic solvent is reported. Potentiodynamic and potentiostatic studies indicated that PdCoNPs were electrodeposited by multiple nucleation of 3D bimetallic centers with mass transferred-controlled growth. Potentiostatic current density transients (j-t) were adequately fitted by a theoretical model that describes the kinetics of nucleation and diffusion-controlled growth of bimetallic phases and the number density of active sites for PdCoNPs nucleation (N0) and their nucleation frequency, A, was determined as a function of the applied potential. Scanning electron microscopy imaging of the GCE electrodeposited with PdCoNPs showed that sizes and particle number density of these PdCoNPs depend on both the applied potential and the deposition time considered. At -0.42 V and 10 s the PdCoNPs had (30 ± 4) nm as average size and a particle number density of (4.23 ± 0.33) x1010 PdCoNPs cm–2. EDS, XRD and XPS observations indicated the presence of Pd and Co. forming a PdCo alloy as zero and bivalenced oxidation states. GCE/PdCoNPs depict higher mass activity towards FAOR than GCE/PdNPs and other modified electrodes reported in the literature.

Design Strategy and Application of Deep Eutectic Solvents for Green Synthesis of Nanomaterials

“…The electrodeposition and electrochemical behavior of alloys in DESs have been extensively addressed, such as Fe-Cr [ 155 , 156 ], Cu-Au [ 157 ], Ni-Mo [ 158 ], Au-Pt [ 159 ], Ni-Co [ 160 ], Cu-Sn [ 164 ], Zn-Sn [ 165 ], Pd-Co [ 161 ], and Co-Pt [ 162 ]. The electrodeposition of more than one metal often forms different structures and properties [ 166 , 167 ].…”

“…The grains of deposits were identical and had a size of about 20 nm. Recently, the fabrication of Pd-Co alloy nanoparticles (PdCoNPs) has been described to obtain by an electrochemical process in DES-based ChCl-U [ 161 ]. The potentiostat investigated the formation of PdCoNPs on glassy carbon (GC) electrodes from their precursors dissolved in the ChC-U.…”