Study of PtPd Bimetallic Nanoparticles for Fuel Cell Applications

Abstract

Bimetallic nanoparticles are of special interest for their potential applications for fuel cells, mainly for portable power applications. Among the bimetallic systems, Pt-Pd bimetallic nanoparticles have received great interest as they can be widely used as effective catalysts for various electrochemical reactions. In this work, Pt-Pd alloy bimetallic nanoparticles were synthesized through a chemical reduction method. The nanoparticles were characterized using aberration-corrected scanning/transmission electron microscopy (STEM). Also, parallel beam X-Ray diffraction analysis was carried out to evaluate the crystallographic structure. High-angle annular dark field (HAADF)-STEM images of the Pt-Pd bimetallic nanoparticles were obtained. The contrast of the images shows that the nanoparticles have an alloy structure with an average size of 7.15 nm. To understand the properties of the bimetallic nanoparticles, it is necessary to know the distribution of the elements in the nanostructure. We have used a semi-quantitative method to analyze the HAADF-STEM images, which allowed us to measure the total intensity of the scattered electrons for each atomic column. HAADF-STEM images of the Pt-Pd bimetallic nanoparticles were compared directly with image simulations, good agreement between simulation and experimental images was found. Cyclic voltammetry studies were carried out to analyze the electrochemical behavior of the bimetallic nanoparticles.

Self‐Organization Based Fabrication of Bimetallic PtPd Nanoparticles on Transparent Conductive Oxide Substrates

“…It can be clearly seen that the position of the (111) peak of PtPd (40.00°) is between that of pure Pt (39.89°) and pure Pd (40.15°) NPs. This is a clear indication of the formation of PtPd alloy . This is consistent to the fact that the Pt‐Pd system shows no (or negligible) miscibility gap for the whole range of concentrations, forming continuous and homogeneous solid solutions across the entire range of composition by alloying …”

“…Indeed, Pd is able to absorb large amounts of hydrogen, but its hydrogen solubility decreases as the nanoparticle size decreases; on the other hand, Pt NPs exhibit effective hydrogen storage ability, although bulk Pt is a poor hydrogen absorber . These differences have prompted researchers to look for a possible use of these NPs in PtPd bimetallic structure to take advantage of the synergistic combination of the properties of both metals in the nanoscale form . In particular, in the field of catalysis, bimetallic NPs show superior catalytic properties than their monometallic counterparts .…”

“…These differences have prompted researchers to look for a possible use of these NPs in PtPd bimetallic structure to take advantage of the synergistic combination of the properties of both metals in the nanoscale form . In particular, in the field of catalysis, bimetallic NPs show superior catalytic properties than their monometallic counterparts . For hydrogen storage applications, the amount of hydrogen absorption of Pd/Pt NPs was found to be greater than that of the single components …”

Atomic Surface Segregation and Structural Characterization of PdPt Bimetallic Nanoparticles

“…The difference in intensity brightness is an indicative of the presence of both Pd and Pt atoms at the surface. A study about the identification of the atoms in PdPt bimetallic alloy nanoparticles using HAADF-STEM images has been reported previously by our group [35]. This study showed a method semi-quantitative to analyze the atomic distribution of the elements which is dependent of their atomic number.…”

A ternary SnS1.26Se0.76 alloy for flexible broadband photodetectors

“…1(j) and (k) atomic-resolution HAADF and BF STEM images of the SnS 1.26 Se 0.76 ake viewed from the [001] axis. Since intensity of an atomic column in a HAADF STEM imaging mode is proportional to Z 1.7 (Z is atomic number), [32][33][34] the brightest spots (corresponding to the highest intensity line prole in Fig. S1(c) †) represent the Sn atomic columns (Z ¼ 50), while the medium-brightness and lowest-brightness spots (corresponding to the medium-high and lowest intensity line prole in Fig.…”