scholarly journals Surface facet dependence of competing alloying mechanisms

2020 ◽  
Vol 153 (24) ◽  
pp. 244702
Author(s):  
Yicheng Wang ◽  
Konstantinos G. Papanikolaou ◽  
Ryan T. Hannagan ◽  
Dipna A. Patel ◽  
Tedros A. Balema ◽  
...  
Keyword(s):  
Surface Facet

Strained lattice platinum–palladium alloy nanowires for efficient electrocatalysis

2020 ◽  
Vol 7 (8) ◽  
pp. 1713-1718 ◽  
Author(s):  
Mengyun Ren ◽  
Fangfang Chang ◽  
Ruifang Miao ◽  
Xianhong He ◽  
Lin Yang ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Palladium Alloy ◽  
Direct Alcohol Fuel Cells ◽  
Alcohol Fuel ◽  
Alloy Nanowires ◽  
Alloy Catalysts ◽  
Surface Facet

The ability to manipulate Pt-based alloy catalysts with controllable compositions and the type of surface facet is important for advancing direct alcohol fuel cells (DAFEs).

Surface Facet of Palladium Nanocrystals: A Key Parameter to the Activation of Molecular Oxygen for Organic Catalysis and Cancer Treatment

2013 ◽  
Vol 135 (8) ◽  
pp. 3200-3207 ◽  
Author(s):  
Ran Long ◽  
Keke Mao ◽  
Xiaodong Ye ◽  
Wensheng Yan ◽  
Yaobing Huang ◽  
...  
Keyword(s):  
Cancer Treatment ◽  
Molecular Oxygen ◽  
Organic Catalysis ◽  
Surface Facet ◽  
Key Parameter

Simple synthesis and surface facet-tuning of ultrathin alloy-shells of Au@AuPd nanoparticles via silver-assisted co-reduction onto facet-controlled Au nanoparticles

2018 ◽  
Vol 6 (17) ◽  
pp. 7675-7685 ◽  
Author(s):  
Cuixia Bi ◽  
Yahui Song ◽  
Hongpeng He ◽  
Chenshuo Wu ◽  
Wei Du ◽  
...  
Keyword(s):  
Au Nanoparticles ◽  
Simple Synthesis ◽  
Co Reduction ◽  
Surface Facet

The presence of silver on the surfaces of preformed Au nanoparticles is the key for the formation of ultrathin AuPd alloy-shells.

scholarly journals Surface Energy of Au Nanoparticles Depending on Their Size and Shape

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 484 ◽  
Author(s):  
David Holec ◽  
Phillip Dumitraschkewitz ◽  
Dieter Vollath ◽  
Franz Dieter Fischer
Keyword(s):  
Surface Energy ◽  
Surface Area ◽  
Complex Structure ◽  
Characteristic Size ◽  
Bulk Crystals ◽  
Size And Shape ◽  
Nanoparticle Shape ◽  
Universal Power Law ◽  
Atomistic Study ◽  
Surface Facet

Motivated by often contradictory literature reports on the dependence of the surface energy of gold nanoparticles on the variety of its size and shape, we performed an atomistic study combining molecular mechanics and ab initio calculations. We show that, in the case of Au nanocubes, their surface energy converges to the value for ( 0 0 1 ) facets of bulk crystals. A fast convergence to a single valued surface energy is predicted also for nanospheres. However, the value of the surface energy is larger in this case than that of any low-index surface facet of bulk Au crystal. This fact can be explained by the complex structure of the surface with an extensive number of broken bonds due to edge and corner atoms. A similar trend was obtained also for the case of cuboctahedrons. Since the exact surface area of the nanoparticles is an ill-defined quantity, we have introduced the surface-induced excess energy and discuss this quantity as a function of (i) number of atoms forming the nano-object or (ii) characteristic size of the nano-object. In case (i), a universal power-law behaviour was obtained independent of the nanoparticle shape. Importantly, we show that the size-dependence of the surface energy is hugely reduced, if the surface area correction is considered due to its expansion by the electronic cloud, a phenomenon specifically important for small nanoparticles.

scholarly journals Reaction Mechanism of the Metal Precursor Pulse in Plasma-Enhanced Atomic Layer Deposition of Cobalt and the Role of Surface Facet

2020 ◽  
Author(s):  
Ji Liu ◽  
hongliang lu ◽  
david wei zhang ◽  
Michael Nolan
Keyword(s):  
Reaction Mechanism ◽  
Atomic Layer Deposition ◽  
Density Functional ◽  
Hydrogen Transfer ◽  
Semiconductor Industry ◽  
Atomic Layer ◽  
Potential Candidate ◽  
Metal Precursor ◽  
Layer Deposition ◽  
Surface Facet

Cobalt is a potential candidate in replacing copper for interconnects and has been applied in the trenches and vias in semiconductor industry. A non-oxidizing reactant is required in plasma-enhanced atomic layer deposition (PE-ALD) of thin films of metals to avoid O-contamination. PE-ALD of Co has been demonstrated experimentally, but the growth mechanism and key reactions are not clear. In this paper, the reaction mechanism of metal cyclopentadienyl (Cp, C<sub>5</sub>H<sub>5</sub>) precursors (CoCp<sub>2</sub>) and NH<sub>x</sub>-terminated Co surface is studied by density functional theory (DFT) calculations. The Cp ligands are eliminated by CpH formation via a hydrogen transfer step and desorb from metal surface. The surface facet plays an important role in the reaction energies and activation barriers. The results show that on the NH<sub>x</sub>-terminated surfaces corresponding to ALD operating condition (temperature range 550K to 650K), the two Cp ligands are eliminated completely on Co(100) surface during the metal precursor pulse, resulting in Co atom deposited on the Co(100) surface. But the second Cp ligand reaction of hydrogen transfer is thermodynamically unfavourable on the Co(001) surface, resulting in CoCp fragment termination on Co(001) surface. The final terminations after metal precursor pulse are 3.03 CoCp/nm<sup>2</sup> on NH<sub>x</sub>-terminated Co(001) surface and 3.33 Co/nm<sup>2</sup> on NH<sub>x</sub>-terminated Co(100) surface. These final structures after metal precursor pulse are essential to model the reaction during the following N-plasma step..<br>

scholarly journals Reaction Mechanism of the Metal Precursor Pulse in Plasma-Enhanced Atomic Layer Deposition of Cobalt and the Role of Surface Facet

2020 ◽  
Author(s):  
Ji Liu ◽  
hongliang lu ◽  
david wei zhang ◽  
Michael Nolan
Keyword(s):  
Reaction Mechanism ◽  
Atomic Layer Deposition ◽  
Density Functional ◽  
Hydrogen Transfer ◽  
Semiconductor Industry ◽  
Atomic Layer ◽  
Potential Candidate ◽  
Metal Precursor ◽  
Layer Deposition ◽  
Surface Facet

Cobalt is a potential candidate in replacing copper for interconnects and has been applied in the trenches and vias in semiconductor industry. A non-oxidizing reactant is required in plasma-enhanced atomic layer deposition (PE-ALD) of thin films of metals to avoid O-contamination. PE-ALD of Co has been demonstrated experimentally, but the growth mechanism and key reactions are not clear. In this paper, the reaction mechanism of metal cyclopentadienyl (Cp, C<sub>5</sub>H<sub>5</sub>) precursors (CoCp<sub>2</sub>) and NH<sub>x</sub>-terminated Co surface is studied by density functional theory (DFT) calculations. The Cp ligands are eliminated by CpH formation via a hydrogen transfer step and desorb from metal surface. The surface facet plays an important role in the reaction energies and activation barriers. The results show that on the NH<sub>x</sub>-terminated surfaces corresponding to ALD operating condition (temperature range 550K to 650K), the two Cp ligands are eliminated completely on Co(100) surface during the metal precursor pulse, resulting in Co atom deposited on the Co(100) surface. But the second Cp ligand reaction of hydrogen transfer is thermodynamically unfavourable on the Co(001) surface, resulting in CoCp fragment termination on Co(001) surface. The final terminations after metal precursor pulse are 3.03 CoCp/nm<sup>2</sup> on NH<sub>x</sub>-terminated Co(001) surface and 3.33 Co/nm<sup>2</sup> on NH<sub>x</sub>-terminated Co(100) surface. These final structures after metal precursor pulse are essential to model the reaction during the following N-plasma step..<br>

scholarly journals The interplay between surface facet and reconstruction on isopropanol conversion over SrTiO3 nanocrystals

2020 ◽  
Vol 384 ◽  
pp. 49-60 ◽  
Author(s):  
Zhenghong Bao ◽  
Victor Fung ◽  
Felipe Polo-Garzon ◽  
Zachary D. Hood ◽  
Shaohong Cao ◽  
...  
Keyword(s):  
Surface Facet
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