Decoration, Migration, and Aggregation of Palladium Nanoparticles on Graphene Sheets

Abstract

As a two-dimensional carbon nanomaterial, graphene has a high surface area and good chemical stability; therefore, its potential applicability in composite materials and as a catalyst support is high.Here, we report a facile process to decorate graphene sheets with well-dispersed Pd nanoparticles. By the in situ formation and adhesion of Pd nanoparticles to the thermally exfoliated graphene (TEG) sheets suspended in a solvent, a Pd/TEG composite was prepared and characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller (BET) surface area analysis. The migration and aggregation of Pd nanoparticles on the graphene sheets was directly observed by scanning transmission electron microscopy. As the composite was heated to 700 °C, there was little movement of the Pd nanoparticles; on heating to 800 °C, well below the melting temperature, the Pd nanoparticles began to migrate, coalesce, and agglomerate to form larger particles. The aggregation behavior was further confirmed by X-ray diffraction analysis of the Pd/ TEG composite before and after being annealed at 800 °C. The graphene sheets provided a real-time imaging platform with nanometer-scale thickness to study the thermal stability and migratory behavior of nanoscale materials.

Growth morphology and properties of metals on graphene

“…27). In another experiment, it was also shown that Pd nanoparticles on graphene are very stable against aggregation above 800°C [166] which also is consistent with results for E b -E a from DFT calculations. Co NCs on graphene are found to be stable up to 650°C before intercalation taking place at higher temperature [72].…”

One-step synthesis of palladium-gold-silver ternary nanoparticles supported on reduced graphene oxide for the electrooxidation of methanol and ethanol

“…3e), there are two asymmetric peaks at around 340.9 and 335.7 eV. These correspond to 3d 3/2 and 3d 5/2 of the metallic Pd (0) state respectively [40]. There is an increase in the Pd binding energy for Pd-Au-Ag/RGO relative to that of monometallic Pd/RGO [41].…”

Two-Dimensional (2D) Nanomaterials towards Electrochemical Nanoarchitectonics in Energy-Related Applications

“…161,174 Graphene exhibits a wide potential window of 2.5 V in 0.1 M phosphate buffer neutral solution, which is comparable to the traditional glassy carbon electrode (GCE). In this regards, graphene with 2D planar structure employed as a substrate for growing and anchoring noble metal NCs and alloyed metallic NCs, including Pt, 175177 Au, 178 Pd, 179 PtPd, 180 and PtRu 181 to realize high performance electrocatalytic devices (Figure 6a). Zhang et al developed polyelectrolyte poly(diallyldimethylammonium chloride) (PDDA) induced reduction of exfoliated graphite oxide as a facile route to the synthesis of soluble graphene nanosheets.…”