Two-step synthesis of Ir-decorated Pd nanocubes and their impact on the glycerol electrooxidation

Abstract

Despite intense research to synthesize well-ordered noble-metals nanoparticles to understand catalyzed electrochemical reactions, the synthesis and application of multi-metallic well-ordered nanomaterials is still rare. Here, we report a facile strategy for synthesizing Ir-decorated Pd nanocubes (NCs) in one-batch through two sequential chemical reduction processes. Afterwards, the activity of these materials was investigated for glycerol electrooxidation in alkaline medium by cyclic voltammetry and in situ FTIR. Microscopy images and compositional mapping reveal that Ir deposition barely changes the size of the cubes. The bi-metallic nanocubes shifts the onset potential toward lower values, but decreases the current density. The start potential displacement is rationalized as a consequence of a facilitated CO removal and an anticipated carbonate production; while the decrease in current may be a consequence of a reaction with multiple steps, each one extracting a few electrons. FTIR in situ spectra reveal CO2 production only for Ir-Pd NCs, which is due to a massive production of carbonate, which ultimately acidifies the interfacial pH. The protocol of synthesis showed here may be used to study well-ordered multimetallic nanostructures in several applications, not limited for electrocatalysis.