Influence of PtCu/C Catalysts Composition on Electrochemical Characteristics of Polymer Electrolyte Fuel Cell and Properties of Proton Exchange Membrane

Ekaterina Titskaya,Natalia Kononenko,Angelina Pavlets,Anastasia Alekseenko,Irina Falina

doi:10.3390/catal11091063

Ekaterina Titskaya, Natalia Kononenko + Show 3 more

Open Access

https://doi.org/10.3390/catal11091063

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Journal: Catalysts	Publication Date: Aug 31, 2021
Citations: 9	License type: CC BY 4.0

Affiliation: Kuban State University, Southern Federal University

Abstract

The present work aimed to investigate the influence of “weakly bound“ copper dissolution from the surface of bimetallic PtCux/C catalysts on the properties of proton exchange membrane and the membrane electrode assembly (MEA) in general. A number of PtCux/C materials have been obtained by the simultaneous reduction in copper and platinum precursors in the course of liquid-phase synthesis with a varying ratio of metals from PtCu2.0/C to PtCu0.3/C. All bimetallic PtCux/C electrocatalysts after the activation stage exhibit high activity in the oxygen electroreduction reaction. The PtCux/C catalysts in “as prepared” state were tested in MEA. The increase in Cu content in PtCux/C catalysts led to a decrease in current density of MEA while its resistance was almost independent of the Cu fraction in the catalyst. The membrane saturation degree by Cu2+-ions after MEA testing did not exceed 40%, even in the case of the PtCu2.0/C material. The main reason for the degradation of membrane electrode assembly with PtCux/C materials is the transport limitation caused by the contamination of Nafion in three catalytic layer by “weakly bound” copper ions.

Highlights

Proton exchange membrane fuel cells (PEMFC) are an essential part of intensively developing hydrogen energy [1,2,3]
The PtCux/C catalysts characteristics were evaluated by X-ray fluorescence analysis (XRF), X-ray diffraction (XRD) and cycle voltammetry; membrane saturation degree by Cu2+-ions after membrane electrode assembly (MEA) operation was determined from the conductivity data; MEA with PtCux/C catalysts in the “as prepared” state was tested by potentiostatic voltammetry and AC resistance measurements
The set of PtCux/C materials were obtained by the simultaneous reduction in copper and platinum precursors in the course of liquid-phase synthesis; ratio of metals varied from PtCu2.0/C to PtCu0.3/C; total mass fraction of metals changed from 20 to 40%

Summary

Introduction

Proton exchange membrane fuel cells (PEMFC) are an essential part of intensively developing hydrogen energy [1,2,3]. One of the key directions of development in the activity and stability of electrocatalysts for the oxygen reduction reaction (ORR) in PEMFC is obtaining new effective bimetallic materials based on platinum alloyed with transition metals (Ni, Co, Cu, Ag) [9,10,11]. It is known that the contact of bimetallic particles with an electrolyte solution in the cathodic region of the MEA causes the selective dissolution of the alloying metal, mainly from the nanoparticle surface region. The decrease in the proton conductivity of a polymer membrane due to the replacement of protons by multi-charged cations is usually considered as the main reason for the degradation of the characteristics of fuel cells with bimetallic catalysts [14]. The PtCux/C catalysts characteristics were evaluated by X-ray fluorescence analysis (XRF), X-ray diffraction (XRD) and cycle voltammetry; membrane saturation degree by Cu2+-ions after MEA operation was determined from the conductivity data; MEA with PtCux/C catalysts in the “as prepared” state was tested by potentiostatic voltammetry and AC resistance measurements

Characteristics of Bimetallic Catalysts

Materials

Catalyst Preparation

Membrane Transport Properties

MEA Formation and Testing

Conclusions