Effect of Co3O4 Nanoparticles on Improving Catalytic Behavior of Pd/Co3O4@MWCNT Composites for Cathodes in Direct Urea Fuel Cells

Nguyen-Huu-Hung Tuyen,Young-Soo Yoon,Hyun-Gil Kim

doi:10.3390/nano11041017

Nguyen-Huu-Hung Tuyen, Young-Soo Yoon + Show 1 more

Open Access

https://doi.org/10.3390/nano11041017

Copy DOI

Abstract

Direct urea fuel cells (DUFCs) have recently drawn increased attention as sustainable power generation devices because of their considerable advantages. Nonetheless, the kinetics of the oxidation-reduction reaction, particularly the electrochemical oxidation and oxygen reduction reaction (ORR), in direct urea fuel cells are slow and hence considered to be inefficient. To overcome these disadvantages in DUFCs, Pd nanoparticles loaded onto Co3O4 supported by multi-walled carbon nanotubes (Pd/Co3O4@MWCNT) were employed as a promising cathode catalyst for enhancing the electrocatalytic activity and oxygen reduction reaction at the cathode in DUFCs. Co3O4@MWCNT and Pd/Co3O4@MWCNT were synthesized via a facile two-step hydrothermal process. A Pd/MWCNT catalyst was also prepared and evaluated to study the effect of Co3O4 on the performance of the Pd/Co3O4@MWCNT catalyst. A current density of 13.963 mA cm−2 and a maximum power density of 2.792 mW cm−2 at 20 °C were obtained. Pd/Co3O4@MWCNT is a prospectively effective cathode catalyst for DUFCs. The dilution of Pd with non-precious metal oxides in adequate amounts is economically conducive to highly practical catalysts with promising electrocatalytic activity in fuel cell applications.

Highlights

There has been a significant surge in attention paid to energy resources, especially renewable energy
The results demonstrated that the combination of Pd nanoparticles with carbon-supported materials afforded high electrocatalytic performance toward the oxygen reduction reaction (ORR)
The raw Multi-walled carbon nanotubes (MWCNTs) were pretreated with 6.0 M nitric acid and sonicated for 2 h at room temperature, followed by magnetic stirring at 80 ◦ C for the duration of acid treatment of the MWCNTs

Summary

Introduction

There has been a significant surge in attention paid to energy resources, especially renewable energy. Urea and urine fuels are popularly used as low-cost resources, which are prominent for large-scale use in renewable energy. They are safe for storage and transportation in the long run [3]. The direct urea fuel cell (DUFC), as a sustainable power generation device, has been extensively studied because of these undeniable strengths. The kinetics of the oxidation-reduction reactions, electrochemical oxidation and oxygen reduction reactions, in direct urea fuel cells are sluggish; improving the efficiency and performance of these reactions by utilizing highly active noble metals such as platinum has been considered [4,5]

Methods

Results

Conclusion