Ab initio comparative study of C54 and C49 TiSi2 surfaces

Wang, Tao; Oh, Sanghee; Lee, Won–Jae; Lee, Hi‐Deok

doi:10.1016/j.apsusc.2005.07.029

Cited by 15 publications

(11 citation statements)

References 18 publications

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“…With this background information in mind, we see that the deposition of Pt should favor surfaces with low energies. For C49 TiSi 2 , theoretical studies show that b planes are more stable than a and c planes by up to 20% in surface energies; the difference between various planes of C54 TiSi 2 is much less pronounced . The surface energy difference may be an important factor that governs the selective growth.…”

Section: Resultsmentioning

confidence: 99%

“…20 When the interface energy between Pt and the supporting substrate is relatively high, the deposition proceeds via a VolmerÀ Weber island mechanism, where nanoparticles instead the difference between various planes of C54 TiSi 2 is much less pronounced. 25 The surface energy difference may be an important factor that governs the selective growth. It is noted that although Si-termination on the top and bottom (020) surfaces of TiSi 2 nanonets has been unambiguously confirmed, further research is needed to understand why no Pt particles grow on the side surfaces at all.…”

Section: Resultsmentioning

confidence: 99%

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Site-Selective Deposition of Twinned Platinum Nanoparticles on TiSi₂ Nanonets by Atomic Layer Deposition and Their Oxygen Reduction Activities

et al. 2013

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For many electrochemical reactions such as oxygen reduction, catalysts are of critical importance, as they are often necessary to reduce reaction overpotentials. To fulfill the promises held by catalysts, a well-defined charge transport pathway is indispensable. Presently, porous carbon is most commonly used for this purpose, the application of which has been recently recognized to be a potential source of concern. To meet this challenge, here we present the development of a catalyst system without the need for carbon. Instead, we focused on a conductive, two-dimensional material of a TiSi2 nanonet, which is also of high surface area. As a proof-of-concept, we grew Pt nanoparticles onto TiSi2 by atomic layer deposition. Surprisingly, the growth exhibited a unique selectivity, with Pt deposited only on the top/bottom surfaces of the nanonets at the nanoscale without mask or patterning. Pt {111} surfaces are preferably exposed as a result of a multiple-twinning effect. The materials showed great promise in catalyzing oxygen reduction reactions, which is one of the key challenges in both fuel cells and metal air batteries.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Site-Selective Deposition of Twinned Platinum Nanoparticles on TiSi₂ Nanonets by Atomic Layer Deposition and Their Oxygen Reduction Activities

et al. 2013

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“…As a result, its (020) planes are prone to be passivated by elements that can form bonds with Si, such as Cl or H, both abundant in the CVD environment for the synthesis of TiSi 2 nanonets. 38 We, therefore, understood the unique two-dimensional structure as a direct result of the crystal structure. The growth mechanism is proposed as follows.…”

Section: Synthesis and Structure Of Tisi 2 Nanonetsmentioning

confidence: 99%

Titanium silicide nanonet as a new material platform for advanced lithium ion battery applications

et al. 2013

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Compared with competing technologies, rechargeable lithium ion batteries offer relative advantages such as high capacity and long cycle lifetime. Remarkable advances in the development of this technology notwithstanding significant performance improvements are still required to meet society's ever-growing electrical energy storage need. In particular, we long for devices with greater capacity, a higher power rate and a longer cycle lifetime. Aimed at solving challenges associated with poor charge transport within electrode materials, we have recently tested a new, nanonet-based material platform. The nanonet, made of TiSi2 (C49), is similar to the more commonly used porous carbon in that it has high surface area and good electrical conductivity. The key uniqueness of the nanonet lies in that its morphology is well-defined, permitting us to design and test various heteronanostructures. In essence, the TiSi2 nanonet can serve as a charge collector and a mechanical support for the construction of electrodes for a wide range of applications. We show that when combined with Si, an anode with superior performance is obtained. Similarly, a high-performance cathode is enabled by the TiSi2-V2O5 combination.

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“…For some high‐temperature materials, the phase transition can happen easily under high‐temperature or high‐pressure environment. For example, Chen et al have pointed out that MoSi 2 undergoes a phase transition from tetragonal C11 b structure to hexagonal C40 structure when the temperature is above 1900°C Moreover, the first formed C49‐TiSi 2 can change into C54 phase at the higher temperature …”

Section: Introductionmentioning

confidence: 99%

Insight into the structures, melting points, and mechanical properties of NbSi₂ from first‐principles calculations

Wang

Pan

2019

J Am Ceram Soc

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Studies are carried out on the equilibrium structural, mechanical properties, and melting points of NbSi 2 with four ground-state crystal structures (C40, C11 b , C54, and C49) using first-principles approach. By means of the calculated formation enthalpies and phonon dispersion, it is found that these NbSi 2 phases are thermodynamically and dynamically stable. C54-NbSi 2 is uncovered to possess the lowest energy and formation enthalpy, implying that it is expected to be the most favorite structure for NbSi 2 . The results of the calculated elastic constants reveal that four NbSi 2 phases are mechanically stable. We further find that the mechanical properties of C54-NbSi 2 are superior to those of the other NbSi 2 phases. The melting points of these NbSi 2 phases are calculated to examine their thermal stability. The elastic anisotropy is calculated and discussed using three patterns. The results prove that C54-and C40-NbSi 2 have good elastic isotropy, as confirmed by the given three-dimensional plots of elastic moduli. Analyzing the difference charge density and Mulliken overlap population provides the explanation about the relationship between bonding characteristics and mechanical properties. K E Y W O R D Sfirst-principles theory, mechanical properties, NbSi 2 , structure

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Ab initio comparative study of C54 and C49 TiSi2 surfaces

Cited by 15 publications

References 18 publications

Site-Selective Deposition of Twinned Platinum Nanoparticles on TiSi₂ Nanonets by Atomic Layer Deposition and Their Oxygen Reduction Activities

Site-Selective Deposition of Twinned Platinum Nanoparticles on TiSi₂ Nanonets by Atomic Layer Deposition and Their Oxygen Reduction Activities

Titanium silicide nanonet as a new material platform for advanced lithium ion battery applications

Insight into the structures, melting points, and mechanical properties of NbSi₂ from first‐principles calculations

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Ab initio comparative study of C54 and C49 TiSi2 surfaces

Cited by 15 publications

References 18 publications

Site-Selective Deposition of Twinned Platinum Nanoparticles on TiSi2 Nanonets by Atomic Layer Deposition and Their Oxygen Reduction Activities

Site-Selective Deposition of Twinned Platinum Nanoparticles on TiSi2 Nanonets by Atomic Layer Deposition and Their Oxygen Reduction Activities

Titanium silicide nanonet as a new material platform for advanced lithium ion battery applications

Insight into the structures, melting points, and mechanical properties of NbSi2 from first‐principles calculations

Contact Info

Product

Resources

About

Site-Selective Deposition of Twinned Platinum Nanoparticles on TiSi₂ Nanonets by Atomic Layer Deposition and Their Oxygen Reduction Activities

Site-Selective Deposition of Twinned Platinum Nanoparticles on TiSi₂ Nanonets by Atomic Layer Deposition and Their Oxygen Reduction Activities

Insight into the structures, melting points, and mechanical properties of NbSi₂ from first‐principles calculations