Influence of Solvents on the Electroactivity of PtAl/rGO Catalyst Inks and Anode in Direct Ethanol Fuel Cell

Thu Ha Thi Vu,Minh Dang Nguyen,Anh Tuan Ngoc Mai,Marinos Pitsikalis

doi:10.1155/2021/6649089

Abstract

This paper presents research on the effects of common solvents such as n-butyl acetate, isopropanol, and ethanol on the properties and electroactivity of catalyst ink based on PtAl/rGO. The inks prepared by mixing PtAl/rGO catalyst, Nafion solution (5 wt%), and solvent were coated on carbon cloth by the spin coating method. The results obtained showed that ethanol was the most suitable solvent for the preparation of catalyst ink with a volume ratio between catalyst slurry and solvent of 1 : 1 (CI-EtOH (1/1) ink). The surface of the CI-EtOH (1/1) coated electrode was smooth, flat, and even and had no cracks due to the increase of Nafion mobility, resulting in significant improvement in the interaction between Pt particles and ionomer. Moreover, the electrochemical activity of the CI-EtOH (1/1) ink in ethanol electrooxidation reaction, in both acidic and alkaline media, has the highest value, with the forward current density, IF, reaching 1793 mA mgPt−1 and 4751 mA mgPt−1, respectively. In the application in direct ethanol fuel cell (DEFC), the CI-EtOH ink-coated anode also exhibited the highest power density in both PEM-DEFC (with a proton exchange membrane) and AEM-DEFC (with an anion exchange membrane) at 19.10 mW cm−2 and 27.07 mW cm−2, respectively.

Highlights

Nowadays, the replacement of traditional fossil fuels and reducing greenhouse gas emissions have attracted much attention
E catalyst layers called the heart of the fuel cell are prepared from catalyst inks that are a mixture of a catalyst, an ionomer and/or a hydrophobic agent, and a certain solvent. ere are two main membrane electrode assembly (MEA) preparation processes [2], including catalyst coated on the membrane (CCM) and catalyst coated on the substance (CCS)
Good ink is a combination that has homogeneous dispersion of catalyst particles and Nafion in a suitable solvent, which are as well-dispersed as a catalyst on the electrode. e performance of catalyst layers with an advanced ink has been significantly improved by employing different fabrication methods [3, 7, 15,16,17], researching on the dielectric constant of dispersing solvent [18] and the catalyst ink composition [9, 19,20,21], changing the concentration of Nafion, and studying an agglomeration in the catalyst ink layers [3, 22,23,24]

Summary

Introduction

The replacement of traditional fossil fuels and reducing greenhouse gas emissions have attracted much attention. Direct ethanol fuel cells (DEFCs) that show remarkable advantages such as safety and a high energy density [1], 6.28 kWh L−1, could become a good solution. E catalyst layers called the heart of the fuel cell are prepared from catalyst inks that are a mixture of a catalyst, an ionomer (mostly Nafion) and/or a hydrophobic agent, and a certain solvent. Ere are two main MEA preparation processes [2], including catalyst coated on the membrane (CCM) and catalyst coated on the substance (CCS). Some solvents are studied in catalyst ink preparation such as water [3], n-propanol, ethylene glycol [4,5,6,7], 1-hexanol [8], tetrahydrofuran, isopropanol [9,10,11,12], n-butyl acetate [11], ethanol [9, 12,13,14], dimethyl sulfoxide, and N-methyl-2pyrrolidone [14]

Methods

Results

Conclusion