Chemical Tuning of Metal Nanocatalysts Interface for ORR Electrocatalysis

Abstract

A series of surface-functionalized gold nanocatalysts are synthesized. Through diazonium chemistry, calix[4]arene molecules are grafted at the gold surface. Sharing the same anchoring function and a common backbone, the calix[4]arene ligands possess distinct terminal chemical functions where the length, hydrophobic nature and oxygen affinity are varied. Thanks to the versatility of the calix[4]arene platform, a focused tuning of the solid/liquid interface with tail groups could be achieved. Electrocatalytic tests demonstrate the influence of the tails group on the ORR performances, including efficiency, selectivity and durability. Beyond a pure geometric effect, we show that chemical properties of the ligands could effectively tune the interactions between the metallic catalyst and the electrolyte and reactants.

Chemical Surface Grafting of Pt Nanocatalysts for Reconciling Methanol Tolerance with Methanol Oxidation Activity

“…In addition, herein, the calix[4]arene tetradiazonium cation is designed to form a monolayer onto the surface, as previously demonstrated, which stands in contrast with what is generally observed with simple aryl diazonium salts [27,31] . In a previous work, a similar synthetic strategy using a series of calix[4]arene‐tetradiazonium salts has led to the ultra‐thin coating of small gold nanoparticles (6 nm) [32] . Figure 2 shows representative HRTEM images of the as‐prepared Pt nanoparticles with an average core size equal to 3.4 nm and a rather narrow dispersity.…”

“…[27,31] In a previous work, a similar synthetic strategy using a series of calix [4]arene-tetradiazonium salts has led to the ultrathin coating of small gold nanoparticles (6 nm). [32] Figure 2 shows representative HRTEM images of the as-prepared Pt nanoparticles with an average core size equal to 3.4 nm and a rather narrow dispersity. The sizes of the Pt CF 3 NPs are comparable with the typical dimensions of commercial Pt/C catalysts used as comparative sample in the study (Figure S1).…”