Defect-Dominated Shape Recovery of Nanocrystals: A New Strategy for Trimetallic Catalysts

Wu, Yuen; Wang, Dingsheng; Chen, Xiaobin; Zhou, Gang; Yu, Rong; Li, Yadong

doi:10.1021/ja4068063

Cited by 97 publications

(93 citation statements)

References 25 publications

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“…Noble metal nanoparticles (NPs) have been extensively studied for various important applications such as fuel cells [1-], catalysis [4][5][6], surface enhanced Raman scattering (SERS), sensors [7], and biomedical applications [8]. From both experimental investigations on single crystal surfaces and theoretical studies, it has been widely reported that many physical and chemical properties are strongly dependent on the atomic arrangements and thus the crystallographic plane on the surface [9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Shape-controlled synthesis of Pt-Ir nanocubes with preferential (100) orientation and their unusual enhanced electrocatalytic activities

Zhong

Liu

et al. 2014

Sci. China Mater.

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Pt-Ir nanocubes with (100)-terminated facets were synthesized for the first time and their unusual high electrocatalytic activity for a model reaction (i.e., ammonia oxidation) was reported. The key parameters in controlling the shape of the PtIr nanocubes were systematically investigated by transmission electron microscopy (TEM). The electrocatalytic activities of the prepared Pt-Ir and pure Pt nanoparticles (NPs) were characterized by cyclic voltammetry (CV). The results showed that the amount of W(CO) 6 and the volume ratio of oleylamine and oleic acid play a significant role in the development of well-defined Pt-Ir nanocubes. The resultant Pt-Ir nanocubes exhibit (100) orientation, which has been confirmed by not only the structural characterization results from high-resolution TEM (HRTEM) and X-ray diffraction (XRD) but also hydrogen desorption profiles obtained from the CV measurements in H 2 SO 4 solution. Lattice contraction of the Pt-Ir nanocubes were suggested by HRTEM and XRD measurements, and the electronic interactions between Pt and Ir in the Pt-Ir nanocubes were demonstrated by X-ray photoelectron spectroscopy. The Pt-Ir nanocubes show higher specific activity than pure Pt nanocubes and much higher specific activity than the polycrystalline Pt-Ir NPs. The much improved specific activity of the Pt-Ir nanocubes could be attributed to the reason that the introduction of Ir in the Pt-Ir nanocubes largely maintains the highly active Pt (100) sites and thus a positive synergistic effect through the addition of Ir to Pt could be achieved due to the possible bifunctional mechanism and the electronic effect.

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Section: Introductionmentioning

confidence: 99%

Shape-controlled synthesis of Pt-Ir nanocubes with preferential (100) orientation and their unusual enhanced electrocatalytic activities

Zhong

Liu

et al. 2014

Sci. China Mater.

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“…Furthermore, the entropic negative contribution to the Gibbs free energy of mixing for the ternary system respect to the two binaries will favorably contribute to stability. So a number of reports have dealt with Pt-based ternary alloy nanoparticles for ORR 29-31, , but none has put effort in tailoring their morphological shape [32][33][34] . Now, on the basis of previous studies, Pt-Co binary alloy catalysts also exhibit high activity and stability [35][36][37][38] and for that reason, spherical PtNiCo ternary alloys have attracted more attention as a family of ORR catalysts that would allow tuning both ORR activity and stability [39][40][41][42] .…”

mentioning

confidence: 99%

Elemental Anisotropic Growth and Atomic-Scale Structure of Shape-Controlled Octahedral Pt–Ni–Co Alloy Nanocatalysts

et al. 2015

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Multimetallic shape-controlled nanoparticles offer great opportunities to tune the activity, selectivity and stability of electrocatalytic surface reactions. However, in many cases, our synthetic control over particle size, composition and shape is limited requiring trial and error.Deeper atomic-scale insight in the particle formation process would enable more rational syntheses. Here we exemplify this using a family of trimetallic PtNiCo nanooctahedra obtained via a low-temperature, surfactant-free solvothermal synthesis. We analyze the competition between Ni and Co precursors under co-reduction "one-step" conditions when the Ni reduction rates prevailed. To tune the Co reduction rate and final content we develop a "two-step" route and track the evolution of the composition and morphology of the particles at the atomic scale.To achieve this, scanning transmission electron microscopy and energy dispersive X-ray elemental mapping techniques are used. We provide evidence of a heterogeneous element distribution caused by element-specific anisotropic growth and create octahedral nanoparticles with tailored atomic composition like Pt 1.5 M, PtM and PtM 1.5 (M=Ni+Co). These trimetallic electrocatalysts have been tested toward the oxygen reduction reaction (ORR), showing a greatly enhanced mass activity related to commercial Pt/C and less activity loss than binary PtNi and PtCo after 4000 potential cycles.Keywords: PtNiCo octahedra, intraparticle composition, anisotropic growth, oxygen reduction reaction. 3Over the past years, extensive research and development has been carried out in fuel cells with the aim of implementing this technology on transportation, stationary and portable power generation 1, 2 . Nevertheless, some issues such as catalysts kinetic limitations, durability and cost must still be addressed before their successful commercialization. Oxygen reduction electrocatalysts are known to play a crucial role on fuel cells performance, being the fundamental studies on the subject still required to overcome these barriers 3,4 . By alloying Pt with other non-noble metals, it is possible to produce cheaper electrocatalysts with novel properties for the oxygen reduction reaction (ORR) due to lattice compression 5,6 and/or modified electronic properties 7,8 . Thus, several studies have shown that binary Pt-M (M=Cr, Mn, Fe, Co, Ni, Cu, V, Ti) nanocrystals (NCs) greatly enhanced the kinetics of the ORR in comparison with standard Pt catalysts 9-11 . However, besides the composition, the intrinsic activity of nanoparticles also depends on their size and shape which strongly determine the atomic surface structure of the nanoparticles [12][13][14][15] . Thus, by controlling the morphology of the NCs it is possible to maximize the exposure of certain facets that exhibit better catalytic properties 16,17 . These are the premises that led to establish {111}-Pt 3 Ni surfaces as the ideal electrocatalyst for the ORR 18,19 . Since then, many synthetic routes to obtain PtNi nanooctahedra, which ideally exhibit 8 face...

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“…55 In this case, the symmetry and registry are conserved across the interface, and only a slight lattice mismatch should be taken into account. This seems to be a common condition such that complex explanation can be avoided.…”

Section: Synthetic Methodologies Of Nhssmentioning

confidence: 99%

“…However, in real NPs, the perfect crystal planes, which are modeled by a vacuum slab, are usually not observed while some puckered or corrugated planes, such as edges and steps, are present on the interface. Li et al 55 reported the growth of Ni domains on concave Pt 3 Ni nanooctahedra ( Figure 5). The concaved Pt 3 Ni nanooctahedra Rational synthesis and structure-property relationships of NHSs B Xu et al were prepared by etching pre-existing PtNi nanooctahedra.…”

Section: Synthetic Methodologies Of Nhssmentioning

confidence: 99%

“…The altered electronic structure would create different adsorption behaviors of the metal components towards reactant or transient species, thereby leading to distinct catalytic properties. For example, Li et al 55 synthesized Pt 3 Ni concave nanooctahedra and then subsequently deposited a third metal. The shape recovery was observed in the subsequent formation of Pt 3 Ni@Au nanooctahedra.…”

Section: Catalytic Propertiesmentioning

confidence: 99%

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Rational synthesis and the structure-property relationships of nanoheterostructures: a combinative study of experiments and theory

Zhou

Wang

2015

NPG Asia Mater

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Nanoheterostructures (NHSs) that combine various nanomaterials into one entity have received an extensive amount of attention in current research. The enhanced performance of the NHSs over their individual constituents have arisen from their unique electronic structure. To rationally synthesize NHSs, two issues need to be addressed. The first issue that should be explored is the mechanism by which the disparate components are integrated into the main structure. The second issue is the relationship between the NHS and its corresponding properties. In this review article, we will focus on these two issues from the perspectives of both experimental and theoretical methodologies.

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Defect-Dominated Shape Recovery of Nanocrystals: A New Strategy for Trimetallic Catalysts

Cited by 97 publications

References 25 publications

Shape-controlled synthesis of Pt-Ir nanocubes with preferential (100) orientation and their unusual enhanced electrocatalytic activities

Shape-controlled synthesis of Pt-Ir nanocubes with preferential (100) orientation and their unusual enhanced electrocatalytic activities

Elemental Anisotropic Growth and Atomic-Scale Structure of Shape-Controlled Octahedral Pt–Ni–Co Alloy Nanocatalysts

Rational synthesis and the structure-property relationships of nanoheterostructures: a combinative study of experiments and theory

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