High‐Index Faceted Platinum Nanocrystals Supported on Carbon Black as Highly Efficient Catalysts for Ethanol Electrooxidation

Zhou, Zhi‐You; Huang, Zhi‐Zhong; Chen, Dejun; Wang, Qiang; Tian, Na; Sun, Shi‐Gang

doi:10.1002/ange.200905413

Cited by 73 publications

(61 citation statements)

References 18 publications

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“…[257] This problem was overcome by Sun, Wang, and co-workers, who have developed an electrochemical method to prepare NPs terminated by high-index facets. [94,[258][259][260][261][262][263] NPs of other preferential shapes, such as concave hexoctahedral (enclosed by {hkl} facets), [264] trapezohedral ({hkk} facets), [263,264] and nanorods (various {hk0} or {hkk} facets) [264,265] as well as metals (Pt, [94,264,266] Pd, [261,264,265] Fe, [267] PdPt, [260] and PtRh), [263] have similarly been produced by adjusting the synthetic conditions. 750 nm) were electrodeposited on a glassy carbon electrode.…”

Section: Electrochemistry At Preferentially Shaped Nanoparticlesmentioning

confidence: 99%

“…A further enhancement in specific activity has been demonstrated by modifying the high-index facets of preferentially shaped NPs with a second metal beneficial for a specific reaction, such as Pd for formic acid oxidation [260] or Rh for ethanol oxidation. [259] Furthermore, smaller NPs of this type are relatively unstable due to lower stabilization from the bulk material, and adsorption and reaction of species during electrocatalysis may cause small NPs to change their shape and lose the enhanced activity. [270] Although the use of tailored, preferentially shaped NPs (either enclosed by basal planes or by high index facets) is a seemingly straightforward approach to boost the catalytic activity for some reactions, such NPs are quite large (typically > 10 nm for basal plane faceted NPs and 20-150 nm for highindex NPs) compared to commercial catalysts (2-4 nm).…”

Section: Electrochemistry At Preferentially Shaped Nanoparticlesmentioning

confidence: 99%

“…These NPs then underwent dissolution/reprecipitation cycles to form tetrahexahedral NPs of 20-220 nm size with 24 {hk0} facets (Figure 8 c). [94,[258][259][260][261][262][263] NPs of other preferential shapes, such as concave hexoctahedral (enclosed by {hkl} facets), [264] trapezohedral ({hkk} facets), [263,264] and nanorods (various {hk0} or {hkk} facets) [264,265] as well as metals (Pt, [94,264,266] Pd, [261,264,265] Fe, [267] PdPt, [260] and PtRh), [263] have similarly been produced by adjusting the synthetic conditions. [257] NPs prepared by this method have been employed for a variety of electrocatalytic reactions which are known to be promoted by defects and other low-coordination sites (ethanol oxidation on Pt [94,262,264] or Pd, [261,264,265] formic acid oxidation [94] and nitric oxide reduction on Pt, [266] and nitrite reduction on Fe).…”

Section: Electrochemistry At Preferentially Shaped Nanoparticlesmentioning

confidence: 99%

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Electrochemistry of Nanoparticles

et al. 2014

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Metal nanoparticles (NPs) find widespread application as a result of their unique physical and chemical properties. NPs have generated considerable interest in catalysis and electrocatalysis, where they provide a high surface area to mass ratio and can be tailored to promote particular reaction pathways. The activity of NPs can be analyzed especially well using electrochemistry, which probes interfacial chemistry directly. In this Review, we discuss key issues related to the electrochemistry of NPs. We highlight model studies that demonstrate exceptional control over the NP shape and size, or mass-transport conditions, which can provide key insights into the behavior of ensembles of NPs. Particular focus is on the challenge of ultimately measuring reactions at individual NPs, and relating the response to their structure, which is leading to imaginative experiments that have an impact on electrochemistry in general as well as broader surface and colloid science.

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Section: Electrochemistry At Preferentially Shaped Nanoparticlesmentioning

confidence: 99%

Section: Electrochemistry At Preferentially Shaped Nanoparticlesmentioning

confidence: 99%

Section: Electrochemistry At Preferentially Shaped Nanoparticlesmentioning

confidence: 99%

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Electrochemistry of Nanoparticles

et al. 2014

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“…The concave Pd polyhedra exhibit the lowest ECSA among the four catalysts, which may be caused by their large particle size. According to the above results, it can be safely concluded that the observed high electrocatalytic activities of the concave Pd polyhedra could be attributed to the presence of the large number of atomic steps [35] and/or surface relaxation. The peak current density of ethanol oxidation in the positive potential scan was 1.41, 0.36, 0.21, and 0.61 mA cm À2 on the concave Pd polyhedra, truncated Pd octahedra, Pd black, and Pd/C, respectively (Figure 3 a).…”

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confidence: 72%

Growth of Concave Polyhedral Pd Nanocrystals with 32 Facets Through In Situ Facet‐Selective Etching

et al. 2013

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The control over crystal-plane exposure of nanoparticles in a variety of shapes and material types (such as metals and metal oxides) has attracted much attention because fascinating properties might be accomplished. [1][2][3] In the case of metallic nanocrystals (NCs), it has been demonstrated that the exposed crystal facets of metallic NCs have a large influence on their catalytic reactivity and selectivity. [4][5][6][7] Recent studies indicate that high-index facets of a face-centered cubic (fcc) metal (e.g., Pd, Pt, and Au) generally exhibit significantly enhanced catalytic activity toward specific reactions compared to low-index facets because of a high density of low-coordinated surface atoms. [8][9][10][11][12][13] However, up to date, studies on the design and synthesis of metallic nanostructures enclosed by high-index facets are still insufficient. High-index facets usually disappear during the growth of NCs due to their high surface energies. [14] However, recent studies have shown that the exposure of high-index facets could be realized by tuning the growth kinetics, [15,16] the selective adsorption of specific chemical species, [17][18][19][20] and their epitaxial growth from seeds terminating in high-index facets. [21,22] Herein, we report a synthetic strategy that allows the highyield fabrication of concave polyhedral Pd NCs with 32 facets that are rich in atomic steps and defects on the surface. This nanostructure was successfully prepared through an in situ facet-selective etching growth route. The vital role that iodide ions (I À ) together with ethanolamine as the surface controller play in the formation of concave polyhedral Pd NCs having catalytic active sites is demonstrated. The concave polyhedral Pd NCs exhibit significantly enhanced specific and mass activities towards the electrooxidation of ethanol in comparison to truncated octahedral Pd NCs and commercial Pd black catalysts with low-index facets.In a typical synthesis of concave polyhedral Pd NCs, poly-(vinyl pyrrolidone) (PVP, M W = 30 000), NaI, and an aqueous Na 2 PdCl 4 solution were mixed together with ethanolamine. The resulting homogeneous solution was transferred to a Teflon-lined stainless-steel autoclave with a capacity of 12 mL. The sealed vessel was then heated at 200 8C for 6 h before it was cooled to room temperature (see the Experimental Section for synthesis details). The resulting products were collected by centrifugation and washed several times with water and ethanol.The representative electron microscopic images of the asobtained Pd NCs are shown in Figure 1. As depicted by transmission electron microscopic (TEM) images in Figure 1 a and Figure S1 c and d in the Supporting Information, the product consists of well-shaped NCs with a yield above 90 % and an average apex-to-apex distance of 50 nm. The nanoparticles display a darker contrast in the center compared to the edges, indicating the possible presence of concave features in the NCs. The scanning electron microscopic (SEM) images shown in Figure 1 b and Figure S1...

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“…[3] This discovery is receiving increasing attention from public and private institutions interested in the setup of fossil fuel-free and environmentally friendly processes. For example, although a variety of metal (e.g., Pt, Pd, and Au) NPs with HIFs have been synthesized through electrochemical square wave potential deposition (SWPD) or wet chemistry methods, [8][9][10][11][12][13][14] the particle sizes are usually much larger than those of practical catalysts (2-10 nm). [7] The exploitation of the catalytic properties of the HIFs depends on the availability of methods capable of generating supported NPs with high-index terminations as well as controlling the particle size and metal loading.…”

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confidence: 99%

Electrochemical Milling and Faceting: Size Reduction and Catalytic Activation of Palladium Nanoparticles

et al. 2012

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Financial support from Ing. Guido Gay (Switzerland) for the project "Conversion of CO 2 in hydrocarbons and oxygenated compounds", from the Ente Cassa di Risparmio Firenze for the HYDROLAB 2 project, from the MIUR (Italy) for the PRIN 2008 project (project number 2008N7CYL5), from the MATTM (Italy) for the PIRODE project (number 94), from the MSE for the PRIT project Industria 2015, and from the Regione Lombardia for the project "ACCORDO QUADRO Regione Lombardia e

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High‐Index Faceted Platinum Nanocrystals Supported on Carbon Black as Highly Efficient Catalysts for Ethanol Electrooxidation

Cited by 73 publications

References 18 publications

Electrochemistry of Nanoparticles

Electrochemistry of Nanoparticles

Growth of Concave Polyhedral Pd Nanocrystals with 32 Facets Through In Situ Facet‐Selective Etching

Electrochemical Milling and Faceting: Size Reduction and Catalytic Activation of Palladium Nanoparticles

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