Shape‐directed platinum nanoparticle synthesis: nanoscale design of novel catalysts

Leong, G. Jeremy; Schulze, Maxwell C.; Strand, Matthew B; Maloney, David J.; Frisco, Sarah; Dinh, Huyen N.; Pivovar, Bryan S.; Richards, Ryan M.

doi:10.1002/aoc.3048

Cited by 98 publications

(88 citation statements)

References 223 publications

(681 reference statements)

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“…nanomaterials [8][9][10][11][12][13][14][15][16][17]. Regarding the electrochemical characterization of Pt surfaces, this type of studies has been mainly performed in acid medium.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Understanding CO oxidation reaction on platinum nanoparticles

Arán‐Ais

Vidal‐Iglesias

Farias

et al. 2017

Journal of Electroanalytical Chemistry

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To understand how the CO oxidation reaction proceeds on nanoparticles, which have complex surface structures, the behavior of the nanoparticles for the reaction has to be related to that of single crystal electrodes with a well-defined surface structure.However, the direct extrapolation of the results is not possible because significant differences in the behavior between both type of surfaces are observed. In single crystal electrodes in both acidic and alkaline media, the reaction initiates on defects on the CO adlayer. These defects can be already present on the surface, as surface defects or steps, or generated during the formation of the CO adlayer. In the case of steps, the oxidation starts on the lower part of the step. The only difference between the reaction behavior between acidic and alkaline solutions is the lower mobility of the CO in alkaline solutions, which generates adlayers with higher number of defects and give rise to multiple stripping peaks in stepped surfaces. Using these results, the differences of the behavior between single crystal electrodes and nanoparticles can be rationalized. In spite of the fact that nanoparticles have small ordered domains, the presence of sites in which the reaction is initiated, equivalent to the site in the lower part of the step, is almost negligible, and thus, the oxidation reaction takes place at higher potential values A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 than in stepped surfaces with similar domain size. Also the effect of nanoparticle agglomeration in the oxidation has been rationalized.nanomaterials [8][9][10][11][12][13][14][15][16][17]. Regarding the electrochemical characterization of Pt surfaces, this type of studies has been mainly performed in acid medium. It is important to bear in mind that for this purpose, it has to be considered that the nanoparticles are not perfect surfaces, showing different type of sites on their surfaces. In addition, and unlike single crystal basal planes, which present ideal infinite terraces, nanoparticles possess shorter and narrower ordered domains. Even in the case of stepped surfaces where the width of the terrace is controlled, the length of the terrace is ideally infinite. The first manuscript where CO oxidation was evaluated with shape-controlled nanoparticles was reported by

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“…nanomaterials [8][9][10][11][12][13][14][15][16][17]. Regarding the electrochemical characterization of Pt surfaces, this type of studies has been mainly performed in acid medium.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Understanding CO oxidation reaction on platinum nanoparticles

Arán‐Ais

Vidal‐Iglesias

Farias

et al. 2017

Journal of Electroanalytical Chemistry

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“…On a fundamental level, the interest stems from the effects of the particle size on specific applications: the small size means that these particles can not only be effective simply as drug carriers, but also that they have different, new, and potentially useful properties compared to the bulk metal. Size is only one of the several important important ways to tune the properties of nanoparticles: the nature of the metal, its composition, along with its shape have specific effects on the chemical reactions that the nanoparticles can facilitate, both in terms of catalytic activity and reaction specificity . Given that some of the most widely used catalysts are noble metals, research has focused on synthesizing small particles for a variety of catalytic applications .…”

Section: Introductionmentioning

confidence: 99%

Metallic nanocrystals synthesized in solution: a brief review of crystal shape theory and crystallographic characterization

Kappes

Leong

Gilmer

et al. 2015

Crystal Research and Technology

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This article reviews the main theoretical/computational techniques and the experimental characterization methodologies that are used in the quest to investigate the shape, size, composition, and crystallography of metallic nanoparticles. Two morphological regimes are described, one governed by equilibrium thermodynamics, and another in which the shape can be controlled kinetically: in each case, the focus is on key phenomenological effects, ignoring to a large extent the specifics of the materials. For the equilibrium crystal shape, the field has recently experienced developments beyond the basic Wulff construction. For the kinetically controlled case, we argue that models informed by experiments can lead to insights into the growth mechanisms, as well as into the resulting shapes and morphologies. Experimentally, the increasing resolution of characterization techniques can inform and validate the growth models. While ex situ characterization techniques have become de facto standards for investigations of nanoparticles, in situ techniques offer significant advances in spatial and temporal resolution and help establish a fundamental understanding of growth mechanisms.

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“…Controlling the exterior surface structure of the electrode materials can be used to enhance the activity of catalyst, which has been widely applied for the sustainable conversion processes of water‐hydrogen‐oxygen, including the oxygen reduction reaction (ORR), oxygen evolution reaction, and hydrogen evolution reaction (HER) . The configuration of surface electronic structure is closely related to the arrangement of surface atoms of the materials . However, most current systems only focus on the structures, sizes, or components, neglecting the effect of the intrinsic defects of the crystals .…”

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confidence: 99%

Atomic Vacancies Control of Pd‐Based Catalysts for Enhanced Electrochemical Performance

et al. 2017

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difficult to obtain the catalysts without defects. [4] Some studies have demonstrated that the catalysts with defects on the surface possess higher activity than the defect-free ones. [4,[14][15][16] For instance, it has been proved that the activity of the edge carbon is higher than basal plane carbon for the ORR. [17] Meanwhile, S-vacancies in the basal plane of MoS 2 provide more exposed Mo atoms to directly bind with hydrogen. [18] The catalysts with controllable defects have great potential for high activity and the commercialization of the noble metal catalysts.Fuel cells are high-efficiency energyconversion devices. [19][20][21][22][23] The best currently known electrocatalysts for ORR and liquid fuels-oxidation reaction are the Ptbased catalysts, which suffers from high cost, undesirable durability, and low CO poisoning tolerance problems. [23] Recently, Pd-based catalysts have been demonstrated to be promising effective catalysts because of their outstanding activities for ORR and electrochemical oxidation of small organic molecules, which show potential alternatives for the Pt-based catalysts. [13,[24][25][26] Previous studies show appreciable enhancement of the activity of the catalysts in water splitting and fuel cells by alloying Pd with the transition metals, exposing the lowcoordinated surface atoms, and altering the distances between surface atoms to control the defect or strain of catalysts. [13,[26][27][28] A range of transition metals, including Fe, Co, and Ni, have been intensively explored into PdCu active bimetallic system by simultaneously decreasing material cost and enhancing Structure-engineered Pd-based catalysts at the atomic level can effectively improve the catalytic performance for oxygen or small organic molecules electrocatalysis, comparable to or even superior to that of commercial Pt/C. Here, PdCuCo anisotropic structure (AS) electrocatalysts are synthesized with abundant vacancy defects on the exterior surface, which is unambiguously verified by aberration-corrected transmission electron microscopy. The PdCuCo-AS with vacancy (v-PdCuCo-AS) shows excellent electrochemical activity toward oxygen reduction (ORR) and oxidation of alcohols. The mass activity of the v-PdCuCo-AS is 0.18 A mg −1 at 0.9 V versus reversible hydrogen electrode (RHE), which is 15.55 times larger than that of the commercial Pd/C catalyst in acidic electrolyte. According to the theoretical calculations, this significant improvement can be understood as a result of the promoted charge transfer by polarized electronic structures of the v-PdCuCo-AS in the processes of ORR. The synergistic effect of the correlated defects and the compressive strain caused by the doping Co and Cu atoms effectively improve the electrocatalysis activity for the ORR in acidic/alkaline electrolyte on the v-PdCuCo-AS stems. This approach provides a strategy to design other AS structures for improving their electrochemical performance. Electrocatalysis

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Shape‐directed platinum nanoparticle synthesis: nanoscale design of novel catalysts

Cited by 98 publications

References 223 publications

Understanding CO oxidation reaction on platinum nanoparticles

Understanding CO oxidation reaction on platinum nanoparticles

Metallic nanocrystals synthesized in solution: a brief review of crystal shape theory and crystallographic characterization

Atomic Vacancies Control of Pd‐Based Catalysts for Enhanced Electrochemical Performance

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