Platinum nanoclusters made by gas-diffusion electrocrystallization (GDEx) as electrocatalysts for methanol oxidation

Abstract

The development of high-performance electrocatalysts is critical for enhancing the performance and commercial viability of direct methanol fuel cells (DMFCs), which hold the potential to transform the way we power portable electronics and off-grid systems. In this study, we have employed the gas-diffusion electrocrystallization process (GDEx) at room temperature to synthesize platinum nanoclusters (NCs), using different concentrations of polyvinylpyrrolidone (PVP) to stabilize the NPs. The morphology, structure, and composition of the Pt NCs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Single-particle inductively coupled plasma-sector field mass spectrometry (spICP-SFMS) and X-ray diffraction (XRD). Moreover, we assessed the electrocatalytic activity of the Pt NCs for methanol oxidation in both acidic and alkaline media. TEM and SEM analyses revealed Pt NCs of 30 nm-60, composed of much smaller primary nanoparticles with a diameter ranging from 2-4 nm. PVP played a crucial role in preventing diffusion limited aggregation of the Pt NCs. PVP-stabilized GDEx-made Pt NCs demonstrated superior electrocatalytic activity for methanol oxidation compared to aggregated Pt NCs and commercial Pt/C, which can be attributed to the porous structure of the Pt NCs, resulting in a high effective surface area. This study underscores the potential of the GDEx process as a simple and efficient strategy for synthesizing nanomaterials with remarkable catalytic activity and stability for electrochemical energy applications such as direct methanol fuel cells.