Enhancing Intrinsic Electrocatalytic Activity of Pt/C Nanoparticles for
Oxygen Reduction Reaction in Acidic Media by Microwave-Assisted
Synthesis
Authors: Romero Marianela Lopez , Borja Arco Edgar Jesus , Magallon Cacho Lorena , Ramirez Aparicio Jeannete 
Published: April 2024

Abstract:
This study is focused on the enhancement of the intrinsic electrocatalytic activity of Pt nano-particles supported on C (Pt/C NPs) towards Oxygen Reduction Reaction (ORR) in acidic media. The goal was to investigate the effect of microwave-assisted synthesis on the electrocatalytic performance of Pt/C NPs towards ORR. Thus, Pt/C NPs were synthesized using a microwave-assisted method and by a conventional heating method; structural and morphological characteristics were analyzed by X-ray dif-fraction (XRD) and transmission electron microscopy (TEM). Electrochemical studies were performed using the rotating disk electrode technique to evaluate the ORR performance. Microwave-assisted syn-thesis produced Pt/C NPs with a smaller particle size (6.3 ± 0.2 nm) than conventionally synthesized nanoparticles (8.6 ± 0.3 nm). Electrochemical analysis showed that the microwave-synthesized Pt/C NPs exhibited higher mass activity (4.6 ± 0.8 mA･g-1Pt) for ORR compared to conventionally synthesized nanoparticles (1.9 ± 0.4 mA･mA･g-1Pt). These results demonstrate that microwave-assisted synthesis en-hances the intrinsic electrocatalytic activity of Pt/C NPs for ORR in acidic media. These findings have important implications for the development of efficient electrocatalysts for fuel cell applications.

Background:
The synthesis and characterization of platinum nanoparticles on C are crucial for advancing electrocatalysis, particularly in the context of potential applications in fuel cells. This study builds on previous research, focusing on two distinct synthesis methods to enhance our understanding of their im-pact on nanoparticle properties and electrocatalytic performance.

Objective:
To investigate the synthesis efficiency, structural characteristics, and electrocatalytic activities of platinum nanoparticles on C using microwave-assisted heating and conventional synthesis reactor heating. The objective is to discern any significant differences in particle size, structure, and electrocata-lytic performance between the two synthesis methods.

Methods:
The synthesis involved a comparative analysis of platinum nanoparticles using microwave-assisted and conventional heating methods. Chemical composition analysis verified the synthesis efficiency, and structural and morphological characterizations were performed using X-ray Diffraction and Transmission Electron Microscopy. Electrochemical studies employed the rotating disk electrode technique, with activation and evaluation conducted through cyclic voltammetry, and the oxygen reduction reaction studied via linear sweep voltammetry in an acidic media (0.5 mol⋅L-1 H2SO4).

Results:
Well-supported platinum nanoparticles with a face-centered cubic structure were obtained on C using both synthesis methods. However, microwave-synthesized particles (6.3 ± 0.2 nm) exhibited a smaller size compared to conventionally synthesized particles (8.6 ± 0.3 nm). Electrochemical assess-ment revealed superior mass activity for microwave-synthesized material (4.6 ± 0.8 mA･g-1Pt), outper-forming commercial Pt nanoparticles (3.0 ± 0.3 mA･g-1Pt) and conventionally synthesized material (1.9 ± 0.4 mA･mA･g-1Pt).

Conclusion:
This study concludes that microwave-assisted synthesis yields platinum nanoparticles on C with enhanced electrocatalytic performance, as evidenced by the smaller particle size and superior mass activity compared to conventionally synthesized material and commercial Pt nanoparticles. These findings highlight the potential of microwave-synthesized Pt nanoparticles for applications in fuel cells.