Size-Dependent Energy and Adhesion of Pd Nanoparticles on Graphene on Ni(111) by Pd Vapor Adsorption Calorimetry

Abstract

Carbon-supported late transition-metal nanoparticles are promising catalysts and electrocatalysts for wide-ranging applications. However, experimental investigations of the bonding energetics of metal nanoparticles on carbon supports are very limited. Here, we report heats of adsorption of Pd vapor deposited onto single-layer graphene(0001) supported on Ni(111) at 100 and 300 K as Pd grows particles of well-defined size in the range from three atom clusters to 6 nm diameter. Sizes were determined from He + low-energy ion scattering (LEIS). In this size range, the differential heat of Pd adsorption increases from 228 kJ/mol to within 10 kJ/mol of the heat of sublimation of bulk Pd (377 kJ/mol). The chemical potential of metal atoms in these nanoparticles as a function of average particle size was determined from these results. The adhesion energy at the Pd/graphene(0001)/Ni(111) interface was extracted from these data and found to be 3.5 J/m 2 for the largest Pd particles. For the three metal elements that have now been studied (Pd, Ni, and Ag), we found an increase in metal/graphene(0001)/Ni(111) adhesion energy with metal carbophilicity, which we defined here as the heat of C atom adsorption on that metal's (111) surface estimated from published density functional theory calculations.

Tuning the selectivity of CO2 conversion to CO on partially reduced Cu2O/ZnO heterogeneous interface

“…[ 37 ] The Raman spectrum of CZZ shows two characteristic peaks in the range of 300–1000 cm −1 : one is the Zn‐O peak, and the other is the Cu‐O peak, which indicates the presence of Cu 2 O and ZnO on CZZ (Figure 1F). [ 38,39 ] The presence of Cu 2 O/ZnO heterojunctions and metal/oxide heterointerfaces can be proved by the above‐mentioned X‐ray diffraction, transmission electron microscopy, and XPS results. Notably, electron spin resonance (ESR) further confirmed the increase of O vacancies after the construction of heterojunctions in CZZs, which can provide more additional active sites for electrode reactions (Figure 1G).…”

Calorimetric Energies and Chemical Potentials of Metal Atoms in Catalytic Nanoparticles on Oxide and Carbon Supports: Improved Size Dependencies and Adhesion Energies

“…Also shown is the number density of nanoparticles ( n np ) at 300 (red) and 100 K (blue) that resulted from this LEIS fit. Data taken from refs − . Gray brackets indicate data that were not included in the fitting procedure due to possible stabilization at defects.…”

Exceptionally Stable Cobalt Nanoclusters on Functionalized Graphene

“…In other words, δE bind is related to the differential heat of adsorption, as for example, measured by Campbell's group and compared with DFT predictions for other metallic clusters on G/ Ni(111). [42] In Figure 4, we show δE bind calculated both with (central panel) and without anchoring (left panel), for comparison. The calculated anchored Co structures are depicted in Figure 4c (clusters on valley) and d (clusters on ridge).…”