First principles study of doped carbon supports for enhanced platinum catalysts

Holme, Timothy P.; Zhou, Yingke; Pasquarelli, Robert M.; O’Hayre, Ryan

doi:10.1039/b927263a

Cited by 121 publications

(138 citation statements)

References 20 publications

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“…A rst principles study reported that pyrrolic and pyridinic N offered the defect site for the in situ nucleation and growth of Pt NPs due to the induced partial charges on neighboring carbon atoms. 32,39 An improved performances toward ORR of mesoporous N-doped carbons containing mainly quaternary Ngroups was highlighted as a result of the chemical interaction between Pt NPs and N-defects. 40 Besides, pyridinic and graphitic N acted as active sites for contributing to the ORR performances.…”

Section: Resultsmentioning

confidence: 99%

Highly uniform distribution of Pt nanoparticles on N-doped hollow carbon spheres with enhanced durability for oxygen reduction reaction

et al. 2017

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Section: Resultsmentioning

confidence: 99%

Highly uniform distribution of Pt nanoparticles on N-doped hollow carbon spheres with enhanced durability for oxygen reduction reaction

et al. 2017

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“…Chemical modification of the graphene lattice by heteroatom doping is a common way to form anchor sites in graphene. The N-doping of graphene supports can reportedly increase the dispersion of Pt catalysts [15] and prevent Pt agglomeration [16,17]. This improves the catalyst durability and efficiency for the ORR, compared with that of pristine graphene supports.…”

Section: Introductionmentioning

confidence: 97%

Adsorption and Diffusion Properties of a Single Iron Atom on Light-Element-Doped Graphene

Hasegawa

Kunisada

Sakaguchi

2018

e-J. Surf. Sci. Nanotech.

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In this study, we calculated the diffusion of an Fe atom on graphene and various light-element (B, N, O, Si, P, and S)-doped graphene supports, using first-principles calculations based on density functional theory. We focused on dopants that could suppress the detachment and diffusion of an Fe atom. Such doped graphene supports would have strong potential in high-durability fuel cell catalysts and hydrogen storage materials. The Fe atom adsorbs on pristine graphene via ionic bonding. The bonding between the Fe atom and pristine graphene is very weak, and it has a low adsorption energy of −0.61 eV. Doped graphene contains unoccupied localized orbitals. B-, O-, Si-, and P-doped graphene show high adsorption energies of −1.70 eV, −2.70 eV, −1.46 eV, and −1.38 eV, respectively. Thus, these graphene supports could suppress the detachment of Fe nanoclusters and nanoparticles. We demonstrate that these doped graphene supports with high adsorption energies also have high diffusion barriers, which suppresses the agglomeration of Fe nanoclusters and nanoparticles. We conclude that B-, O-, Si-, and Pdoped graphene are promising supports for enhancing the adsorption lifetime of Fe nanoclusters and nanoparticles.

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“…N doping also provides nucleation sites 29 as well as enhances Pt activity, stability and durability. 30,31 Platinized nanowires with high platinum dispersions benefiting from the surface heterogeneity and functionality are compared with commercial catalysts in Table V and the corresponding X-ray diffractograms are shown in Figure 8. Here, a 14 wt% Pt on P-PPy sample PL (Pt-PL) possesses ∼1.9 nm Pt particles, smaller than the commercial catalysts.…”

Section: Resultsmentioning

confidence: 99%

Carbonaceous Nanowire Supports for Polymer Electrolyte Membrane Fuel Cells

Garzón

Wilson

Banham

et al. 2015

J. Electrochem. Soc.

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Carbohydrate-dye combinations were used to form ionically-linked soft templates for the formation of polypyrrole nanowire networks. High yields of nanostructured products were obtained using small amounts of low-cost carbohydrate and dye template materials, the majority of which remained encapsulated within the nanowires. Varying the concentration and the two-part ratio of the templates influenced the length and diameter of the nanofiber segments within the nanowire network. Pyrolysis of the nanowires yielded carbonaceous fibers containing nitrogen heteroatoms, as well as convoluted graphitic domains, well suited for supporting Pt nanoparticles. The resulting high density of nucleation sites enabled the formation of well dispersed, smaller Pt particles compared to commercial catalysts, despite significantly higher support surface loadings. Carbon nanofibers and nanowires with high nitrogen contents potentially offer desirable interfacial properties for electrochemical and other applications due to the nitrogen functionalization of the surface. Relatively high nitrogen content carbons can be obtained by the pyrolysis of conducting polymers such as polyaniline or polypyrrole (PPy). Nitrogen functionalization of the carbon surfaces has been shown advantageous for fuel cell, 1,2 supercapacitor, 3-6 carbon dioxide adsorption, 7,8 and hydrogen storage applications. 9,10Of the two conducting polymers, polypyrrole provides markedly higher pyrolysis yields and better retention of the original structure than polyaniline, as the latter suffers a 96% mass loss with 1000• C pyrolysis.11 Unfortunately, the chemical syntheses of conducting polymer nanofibers and nanowires are not as easily accomplished with pyrrole as with aniline, for the latter will easily form nanofibers.12 While PPy fibers can be formed by seeding with V 2 O 5 13 or bipyrrole, 14 templates, such as dyes, 15 are typically used to form polypyrrole nanofibers or tubes. Of the many hard and soft template-based bulk processes, 16 a procedure for a two-part soft template for pyrrole based on heparin and methylene blue (MB) 17 requires relatively low amounts of template materials, provides a high yield and a desirable nanowire morphology, as well as the ability to tune the nanofiber diameter by adjusting the ratios of the two-parts. This heparin/MB template also tends to create interconnected nanorods that form three-dimensional porous networks 18 that are ideal for providing both conductivity and accessibility. Unfortunately, heparin is very expensive, and a low-cost replacement needs to be identified for the method to be practical. In an analogous process, heparin was first shown to be an effective template for the electropolymerization of pyrrole into nanowire structures. 19Subsequent work by the same group demonstrated that simple and low-cost starch served as an equally effective electropolymerization template. 20In this report, we investigated the effectiveness of starch and other low-cost carbohydrates as replacements for the heparin pairing with MB. We al...

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First principles study of doped carbon supports for enhanced platinum catalysts

Cited by 121 publications

References 20 publications

Highly uniform distribution of Pt nanoparticles on N-doped hollow carbon spheres with enhanced durability for oxygen reduction reaction

Highly uniform distribution of Pt nanoparticles on N-doped hollow carbon spheres with enhanced durability for oxygen reduction reaction

Adsorption and Diffusion Properties of a Single Iron Atom on Light-Element-Doped Graphene

Carbonaceous Nanowire Supports for Polymer Electrolyte Membrane Fuel Cells

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