Pt–Co nanocluster in hollow carbon nanospheres

Abstract

Recently, it has been reported that small Pt/Co bimetallic nanoclusters into hollow carbon spheres (HCS) show outstanding catalytic performances in deriving biomass fuels due to the small particle size and the homogeneous alloying. Thus, the knowledge about the thermal evolution and stability of the nanoclusters into the HCS has a great importance. We have simulated the heating process beyond the melting point for the bare and encapsulated Pt/Co clusters into the HCS with the different sizes of 55, 147, and 309. The different thermodynamic and structural properties of the nanoclusters have also been investigated in this work. Our results show that the nanoclusters are more stable into the HCS than the bare clusters. The melting points of the supported clusters are also higher than the unsupported clusters. The confined nanoclusters have also lower excess energy values than the bare clusters which means that the encapsulation of Pt/Co nanoclusters into the HCS is favorable. The structural investigations show that a core-shell structure cannot be observed for the different supported and unsupported clusters and the initial mixed structure of the different nanoclusters remains also at the melting points. To more investigate this claim, the radial chemical distribution function (RCDF) and radial distribution function (RDF) of the bare and encapsulated clusters have also been calculated and discussed. © 2018 Wiley Periodicals, Inc.

A Theory/Experience Description of Support Effects in Carbon-Supported Catalysts

“…The same tendency ( i.e . a higher melting point of the confined phase related to free NP) was reported for Au–Pd–Pt NP confined in CNT and PtCo NP confined in hollow carbon spheres . For copper it was shown that the melting temperature of the NP decreases with decreasing CNT diameter.…”

“…715,721 It has been clearly demonstrated that these structural changes of confined species has a direct impact on the properties of the NP. The thermal stability of Al, 722 Au, [723][724][725] Au-Pt, 726 Cu, 727,728 Pd, 729 Pd-Pt, 730 Pd-Au-Pt, 731 PtCo, 732 PtCu, 733 or Pt 734 clusters located in the inner cavity of CNT or carbon nanospheres has been studied by MD calculations. In the case of gold, the melting phenomenon starts from the innermost layer, when the freezing one begins from the outermost layer for confined NP.…”

“…a higher melting point of the confined phase related to free NP) was reported for Au-Pd-Pt NP confined in CNT, 731 and PtCo NP confined in hollow carbon spheres. 732 For copper it was shown that the melting temperature of the NP decreases with decreasing CNT diameter. For Pd (Figure 38), contrarily to gold, it is also found that the melting temperature of the confined Pd NP is lower than that of free NP.…”

“…The thermal stability of Al, Au, − Au–Pt, Cu, , Pd, Pd–Pt, Pd–Au–Pt, PtCo, PtCu, or Pt clusters located in the inner cavity of CNT or carbon nanospheres has been studied by MD calculations. In the case of gold, the melting phenomenon starts from the innermost layer, when the freezing one begins from the outermost layer for confined NP.…”

Boron Nitride- and Graphene-Supported Trimetallic Yolk–Shell and Hollow Nanoparticles

“…49 structural stability in comparison to bare Pt/Co nanoclusters. 50 Akbarzadeh et al, again through MD simulations, demonstrated that carbon capsulation of the nanoparticles is an effective way of increasing the thermal and structural stability of the HNPs. 51 Also, Akbarzadeh et al investigated the thermodynamic behavior of graphite-supported Ag NPs by MD simulations.…”