Rapid and Homogeneous Dispersion of Pt Catalyst Particles on Multi-Walled Carbon Nanotubes by Temperature-Controlled Microwave Polyol Method

Abstract

Fuel cells, particularly direct methanol fuel cells (DMFCs), have great potential as mobile power sources. It has been extensively reported that the DMFC performance strongly depends on the electrode catalyst, and many research groups have focused on the preparation of high efficiency cathode catalysts using all types of metal nanoparticle and support. However, most of these methods are either time-consuming with multiple-steps or there is low loading of the nanocatalyst dispersed on the supports. In this study, platinum nanoparticles of uniform diameter (approximately 4.3 nm) were efficiently dispersed on multi-walled carbon nanotubes (MWCNTs) by the temperature-controlled, microwave-assisted polyol method with the addition of sodium dodecyl sulfate (SDS) and [poly(vinyl pyrrolidone)] (PVP). The addition of SDS and PVP in chloroplatinic acid/ethylene glycol (EG) solution can cause the efficient and homogeneous dispersion of the catalyst particles on MWCNTs, enhance the adsorption of platinum particles, and reduce the residue of platinum particles. Moreover, temperature was determined to be the most important factor affecting the reduction of Pt in the process, and large amounts of Pt particles were characterized when the temperature ranged from 140 to 160 C. The results indicate that the optimum temperature ranges from 140 to 160 C, and that the loading amount of Pt/CNTs can reach more than 50 wt % in only 90 s of processing time. The significant improvements in dispersion and loading are due to the ability of SDS, to wrap the PVPstabilized Pt nanoparticles around the surface of the carbon nanotubes. The characterization analyses were conducted by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), and thermal gravimetric analysis (TGA).

Synthesis and Site Structure of a Replica Platinum−Carbon Composite Formed Utilizing Ordered Mesopores of Aluminum-MCM-41 for Catalysis in Fuel Cells

“…1 The morphologic effects of Pt nanoparticles, films, and alloys on the oxygen reduction reaction were reported. 1,21 In contrast that the Pt nanoparticles have been formed on various types of controlled C materials, [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] the electric contact of Pt with C has never been controlled and monitored nanoscopically.…”

“…The control of platinum nanoparticle size between 1.5 and 7 nm supported on carbon is essential in the application to fuel cells and detoxification of exhaust gas from automobiles . Pt nanoparticles on C nanofibers (mean Pt size of 1.7−4 nm), , C nanotubes (mean Pt size of 2−6.7 nm), – ordered mesoporous C (mean Pt size of 1.5−3 nm), – C powder (mean Pt size of 1.6−4.8 nm), – and spherical C (mean Pt size of 2.9 nm) and Pt monolayer on nanoparticles of other metals have been synthesized in narrow particle size distribution.…”

“…In the design of PEFCs, the cathode catalyst for the oxygen reduction reaction (O 2 + 4H + + 4e − → 2H 2 O) is most critical because the physical contact of Pt with C (electric contact), the electrolyte (wet polymer to transport protons), and oxygen gas needs to be enabled at the same time . The morphologic effects of Pt nanoparticles, films, and alloys on the oxygen reduction reaction were reported. , In contrast that the Pt nanoparticles have been formed on various types of controlled C materials, – the electric contact of Pt with C has never been controlled and monitored nanoscopically.…”

Hydrothermal Synthesis of Pt–Ru–W Anode Catalyst Supported on Multi-Walled Carbon Nanotubes for Methanol Oxidation Fuel Cell

“…To compare the electrocatalytic performance of PtRuW/ MWCNTs, PtRu/MWCNTs (with an atomic ratio of 1 : 1) were chosen and prepared using the same procedure. [16][17][18][19][20] X-ray diffraction (XRD) analysis was performed to characterize the crystalline structures of PtRuW/MWCNTs and PtRu/MWCNTs on a Rigaku X-ray diffractometer with a Cu K radiation source ( ¼ 1:5418 A ˚). The morphologies of the samples were observed by transmission electron microscopy (TEM) with a JEOL JEM-4010.…”