Green Fabrication of Supported Platinum Nanoparticles by Supercritical CO₂ Deposition.

Ying-Liang Chen,Yi-Chieh Lai,Mei-Yin Chen,Cheng-Hsien Tsai

doi:10.3390/ma11122587

Abstract

Pt nanoparticles were successfully deposited on uncatalyzed carbon paper by the supercritical CO2 deposition (SCD) method using platinum (II) acetylacetonate as a precursor followed by thermal conversion. A full 24 factorial design (four factors, each with two levels) was used to investigate the main effect of four factors (deposition temperature, deposition time, reduction temperature, and reduction time) and the interaction effects between them. The morphological structures and surface properties of the Pt/carbon paper composite were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM)/energy-dispersive X-ray spectroscopy analyzer (EDS), and high-resolution transmission electron microscopy (HR-TEM). The results of the 24 factorial design showed that Pt loading on the substrate correlated significantly with deposition time, while Pt aggregation slightly increased with the thermal reduction temperature. Data obtained from both XRD and HR-TEM were in good agreement and showed that Pt nanoparticles were homogeneously dispersed on the substrate with diameters of 7.2–8.7 nm.

Highlights

Supported noble-metal nanoparticles have recently been attracting attention in the field of microelectronics, optics, and catalytic applications due to their high activity and stability [1,2,3].Pt nanoparticles are the most effective catalyst known for oxygen reduction, which is widely used for fuel cells [4,5]
Pt nanoparticles were successfully deposited on non-catalyzed carbon paper by the supercritical CO2 deposition (SCD) method using platinum (II) acetylacetonate as a precursor
A 24 factorial design was applied to investigate the influence of parameters on the Pt loading of the Pt/carbon paper composite

Summary

Introduction

Supported noble-metal nanoparticles have recently been attracting attention in the field of microelectronics, optics, and catalytic applications due to their high activity and stability [1,2,3].Pt nanoparticles are the most effective catalyst known for oxygen reduction, which is widely used for fuel cells [4,5]. Since fuel cells play a significant role in the generation of power, much attention has been given to the preparation of high-performance Pt-based nanoparticles for low temperature fuel cells [4,5,6]. These catalysts rely on various conventional techniques such as wet impregnation, spraying, sol-gel, chemical vapor deposition and electro-deposition [7,8]. Among these techniques, several challenges remain, including particle dimensions (size and distribution) and metal loading. The precise shapes and sizes of Pt nanoparticles can be fabricated by the modified version of polyol methods [9,10], the use of toxic and hazardous reagents and solvents in the fabrication are considered an important environmental problem

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Conclusion