Poly (3, 4-ethylene dioxythiophene) Supported Palladium Catalyst prepared by Galvanic Replacement Reaction for Methanol Tolerant Oxygen Reduction

Pandia Rajathi M,Sheela Berchmans

doi:10.1038/s41598-019-55688-5

Abstract

Herein, we propose a facile electrochemical approach for the synthesis of Pd loaded poly 3, 4-ethylenedioxythiophene (PEDOT) electrodeposited on glassy carbon electrode (GCE) resulting in high surface area. The catalyst preparation is initiated with EDOT polymerization on GCE surface by electrochemical potential cycling method, followed by the electrodeposition of Cu from a 2 mM solution of CuSO4 in 0.1 M NaClO4 at a constant potential of +0.34 V vs. SHE in the form of Cu nanocubes on the PEDOT surface. Pd-PEDOT catalyst was then prepared by the partial substitution of copper by galvanic displacement with various concentrations of PdCl2. The prepared Pd/PEDOT electrocatalyst is found to be methanol resistant indicating its usefulness as fuel cell cathode. The prepared catalyst supports two electron transfer of oxygen reduction reaction in 0.5 M H2SO4. The effects of Pd and Cu contents and the quantity of PEDOT, mass and specific activities were studied. At a relatively low Pd loading of 0.57 ng/cm2, the Pd/PEDOT should be a cost-effective alternative cathode catalyst for direct methanol fuel cells, DMFCs. This work explains the usefulness of PEDOT as good catalyst supporting material which is prepared by an eco-friendly electrochemical route.

Highlights

Www.nature.com/scientificreports challenge of development of Pt-free electrocatalysts for ORR with improved catalytic performance and durability
Pd/PEDOT catalyst was prepared on a glassy carbon surface by initially depositing Cu nanocubes on PEDOT surface under constant potential followed by the formation of Pd on Cu by galvanic displacement reaction (GDR)
It indicates the superior tolerance for methanol oxidation as well as supports oxygen reduction reaction with 2e- electron transfer yielding H2O2 which undergoes fast chemical decomposition to water

Summary

Introduction

Www.nature.com/scientificreports challenge of development of Pt-free electrocatalysts for ORR with improved catalytic performance and durability. Conducting polymers are ideal for a broad range of applications because of their special properties, such as high conductivity, stability in air and ease of preparation They can act as a supporting matrix for a dispersed catalyst providing a large surface area that is essential for effective electrocatalysis. In this investigation, the conducting polymer aids high catalytic activity of the nano sized catalytic material. The electrochemical data indicate that the Pd/PEDOT catalyst simultaneously exhibits better activity for oxygen reduction reaction in acid medium along with methanol tolerance and can be used as cathode in methanol fuel cell and for hydrogen peroxide preparation

Methods

Results

Conclusion