Electrochemical Deposition of Pd@Pd(OH) <sub>2</sub> Core-Shell Nanoparticles onto Glassy Carbon from a Deep Eutectic Solvent (Reline) and their Use as Electrocatalyst for the Methanol Oxidation Reaction
L. Juárez-Marmolejo, B. Maldonado-Teodocio, María Guadalupe Montes de Oca-Yemha, M. Romero‐Romo, M. T. Ramírez-Silva, E.M. Arce-Estrada, P. Morales-Gil, Jorge Mostany, Manuel Palomar‐Pardavé
Abstract
Pd@Pd(OH) 2 core–shell nanoparticles were potentiostatically electrodeposited onto a glassy carbon electrode, GCE, from Pd(II) ions dissolved in the reline deep eutectic solvent. It is shown that the GCE/Pd@Pd(OH) 2 -modified electrode displays a high catalytic activity towards the methanol electrochemical oxidation reaction (MOR) in alkaline solution, revealing a mass activity of (2370 ± 450) mA mg Pd −1 at the peak potential (for CVs recorded at 0.1 V s −1 ), much greater than those reported to date for other nanoparticles, namely: Pd, Cu 1 Pd 2 , Pd 4 Ag 1 , PdFe, PtPdPt, Pt or Pt 2 Ru 1 , synthesized by means of technically complicated, expensive and time-consuming methods or electrodeposited from aqueous media. In particular, the steady-state current reported for PdNPs electrodeposited from aqueous media towards MOR depicted values around 3 mA mg Pd −1 , while those from DES (this work) reached values around 42 mA mg Pd −1 . Furthermore, it is shown that the Pd@Pd(OH) 2 nanoparticles displayed excellent poisoning tolerances, from 2 to 8, depending on the applied potential scan rate and anodic switching potential, which remains practically constant after 200 voltammetric cycles.