Reduced-Graphene-Oxide with Dispersed Au-Ir Nanoparticles as Active Support for Pt at low Loadding for Electrocatalytic Oxygen Electroreduction

TL;DR

This study introduces a novel nanocomposite support with dispersed Au-Ir nanoparticles on reduced graphene oxide, enhancing platinum's electrocatalytic activity for oxygen reduction in acidic media, with detailed characterization and performance evaluation.

Contribution

It presents a new synthesis method for Au-Ir-rGO nanocomposites and demonstrates their improved catalytic performance for ORR compared to other supports.

Findings

Au-Ir-rGO support facilitates a near 4-electron ORR mechanism

Platinum on Au-Ir-rGO shows enhanced catalytic activity

The nanocomposite effectively reduces peroxide formation during ORR

Abstract

We report here on a novel and facile techniques for the synthesis nanocomposite based on stable bimetallic catalyst containing iridium and gold nanoparticles electrodeposited on chemically reduced graphene oxide (rGO) sheet admixed with platinum nanoparticles as an efficient electrocatalyst to facilitate the oxygen reduction reaction (ORR) in acidic medium. Raman spectroscopy, infrared spectroscopy (IR), scanning electron microscope (SEM), transmission electron microscope (TEM) methods were employed to characterize the rGO, Au-NPS-rGO, Ir-NPS-rGO, Au-Ir-rGO nanocomposites formed on the electrode surface. Here we present a comparative study into the relative effects of each hybrid nanocomposites: Au-NPS-rGO, Ir-NPS-rGO, Au-Ir-rGO nanocomposites on the performance of platinum nanoparticles towards the oxygen reduction reaction (ORR) in acidic media. For the purposes of comparing the supports, a simple platinum black catalyst is used and the performance isevaluated via direct measurement of peroxide by rotating ring-disk electrode (RRDE) to determine the number of electrons (n) transferred in the ORR. It was found that platinum nanoparticles dispersed within Au-Ir-rGO support follows a quasi 4-electron mechanism (3.99-4 electrons involved) due to that the ORR takes place mainly on the active Pt particles, and produced hydrogen peroxide is reduced at Au-Ir-rGO support.