Fundamental Electrochemical Insights of Vertically Aligned Carbon Nanofiber Architecture as a Catalyst Support for ORR

Elangovan, Ayyappan; Xu, Jiayi; Brown, Emery; Liu, Bin; Li, Jun

doi:10.1149/1945-7111/ab86c1

Cited by 16 publications

(35 citation statements)

References 63 publications

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“…The Pt/VACNF and PtRu/VACNF catalysts showed about 50 % to 100 % higher capacitive background current than the commercial Pt/C and PtRu/C catalysts, which mainly arise from the porous graphite paper substrate as discussed in our previous paper. [17] This obscures the H UPD features and makes it difficult to derive the ECSA accurately using H UPD . Thus, CO stripping was used as the primary method to determine ECSA in this study.…”

Section: Electrochemical Surface Area Evaluationmentioning

confidence: 99%

“…The CVs of Pt/VACNF and PtRu/VACNF have a significant capacitive contribution from the graphite paper substrate as discussed in our previous paper. [17] Hence, to illustrate the true MOR current density, the capacitive contribution needs to be subtracted from the original CV. respectively.…”

Section: Electrocatalytic Activity Towards the Mormentioning

confidence: 99%

“…The fishbone catalyst model was adopted to represent the multiedge vertically aligned carbon nanofiber architecture. [17] Semiperiodic Pt and PtÀ Ru alloy represented by 4-atom Pt 4 and Pt 2 Ru 2 were placed at the open edge as shown in Figures 3 and 5. The CO and OH adsorbates were placed at the top and bridge sites to identify the most stable configurations.…”

Section: Dft Calculationsmentioning

confidence: 99%

“…Previously, we reported a systematic study explaining the role of VACNFs as a catalyst support for the oxygen reduction reaction (ORR) in alkaline media. [17] The Pt-sputtered VACNF catalysts exhibit longer durability, higher tolerance to methanol crossover, and a faster recovery from CO poisoning comparing to the benchmark Pt/C catalysts. This study further reveals the potentials of this 3D architecture as highly effective support for the deposited Pt and PtRu NPs for MOR in both acidic and alkaline electrolytes.…”

Section: Introductionmentioning

confidence: 97%

“…The 3D architectured VACNFs can be used as a unique catalyst support for PGM catalysts. Previously, we reported a systematic study explaining the role of VACNFs as a catalyst support for the oxygen reduction reaction (ORR) in alkaline media [17] . The Pt‐sputtered VACNF catalysts exhibit longer durability, higher tolerance to methanol crossover, and a faster recovery from CO poisoning comparing to the benchmark Pt/C catalysts.…”

Section: Introductionmentioning

confidence: 99%

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Enhancing Methanol Oxidation Reaction with Platinum‐based Catalysts using a N‐Doped Three‐dimensional Graphitic Carbon Support

Elangovan

Sekar

et al. 2020

ChemCatChem

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Nitrogen-doped graphitic carbon materials have been widely used as a catalyst support in the methanol oxidation reaction (MOR). In this study, we report the role of three-dimensionally architectured in-situ N-doped vertically aligned carbon nanofibers (VACNF) as a catalyst support for MOR in acidic and alkaline media. The abundant graphitic edge sites at the sidewall of N-doped VACNF strongly anchor the deposited platinum group metal (PGM) catalysts and induce a partial electron transfer between the PGM catalysts and support. Density Functional Theory (DFT) calculations reveal that the strong metal-support interaction substantially increases the adsorption energy of OH, particularly near the N-doping sites, which helps to compete and remove the adsorbed intermediate species generated during MOR. The PGM catalysts on N-doped VACNF support exhibits CO stripping at lower potentials comparing to the commercial Vulcan carbon support and presents an enhanced electrocatalytic performance and better durability for MOR.

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Section: Electrochemical Surface Area Evaluationmentioning

confidence: 99%

Section: Electrocatalytic Activity Towards the Mormentioning

confidence: 99%

Section: Dft Calculationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Enhancing Methanol Oxidation Reaction with Platinum‐based Catalysts using a N‐Doped Three‐dimensional Graphitic Carbon Support

Elangovan

Sekar

et al. 2020

ChemCatChem

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Theoretical Investigation of the Oxygen Reduction Reaction over Platinum Catalysts Supported by Multi‐Edged Vertically Aligned Carbon Nanofiber for Electrocatalyst Preparation

Elangovan

Liu

et al. 2022

ChemElectroChem

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Vertically aligned carbon nanofibers (VACNFs) are promising supports for oxygen reduction reaction (ORR) electrocatalysts in fuel cells. Although experimentally these catalytic systems have shown great potential, there is lack of molecular understanding of the catalytic sites and reaction mechanisms. This work investigated the origin of the ORR reactivities of the platinum catalysts on multi‐edged VACNFs (Pt/VACNF) using a multiscale modeling approach combining Density Functional Theory (DFT) and classical Molecular Dynamics (MD) simulations. Based on the ReaxFF potential, all nanoscale Pt particles (Pt55, P100, and Pt147) are stabilized by the open edges located axially along the VACNF walls. The calculated first‐shell coordination numbers, CN ${CN}$ , of surface Pt atoms are 6.63, 7.27, and 7.85, respectively, suggesting that the percentage of low coordination sites increases as the particle size decreases. The adsorption energies of OOH, O, and OH on Pt55 were systematically probed using DFT calculations. These adsorption energies retain a linear correlation against the generalized coordination numbers ( CN‾ ${\overline{CN}}$ ). For Pt nanoparticles supported on VACNF, we found that the OOH and OH bind stronger than on Pt (111) by 0.14 and 0.17 eV, respectively, which can hinder the ORR activity with lower limiting potential than Pt (111). Our theoretical prediction is in good agreement with the linear sweeping voltammetry that revealed a left shift of the half‐wave potential.

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N,S‐co‐doped FeCo Nanoparticles Supported on Porous Carbon Nanofibers as Efficient and Durable Oxygen Reduction Catalysts

et al. 2022

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Finding high-performance, low-cost, efficient catalysts for oxygen reduction reactions (ORR) is essential for sustainable energy conversion systems. Herein, highly efficient and durable iron (Fe) and cobalt (Co)-supported nitrogen (N) and sulfur (S) codoped three-dimensional carbon nanofibers (FeCoÀ N, S@CNFs) were synthesized via electrospinning followed by carbonization. The as-prepared FeCoÀ N,S@CNFs served as efficient ORR catalysts in alkaline 0.1 m KOH solutions that were N 2 and O 2saturated.The experimental results revealed that FeCoÀ N,S@CNFs were highly active ORR catalysts with defectrich active pyridinic N and pyrrolic N and metal bonds to N and S atom sites, which enhanced the ORR activity. FeCoÀ N,S@CNFs exhibited a high onset potential (E onset = 0.89 V) and half-wave potential (E 1/2 = 0.85 V), similar to the electrocatalytic activity of commercial Pt/C. Additionally, the durability of the as-prepared FeCoÀ N,S@CNFs catalysts was maintained for 14 h with longterm stability and high tolerance to methanol stability, accounting for their excellent catalytic ability. Furthermore, CoÀ N@CNFs, FeÀ N@CNFs, and varying Fe and Co ratios were compared with those of FeCoÀ

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Fundamental Electrochemical Insights of Vertically Aligned Carbon Nanofiber Architecture as a Catalyst Support for ORR

Cited by 16 publications

References 63 publications

Enhancing Methanol Oxidation Reaction with Platinum‐based Catalysts using a N‐Doped Three‐dimensional Graphitic Carbon Support

Enhancing Methanol Oxidation Reaction with Platinum‐based Catalysts using a N‐Doped Three‐dimensional Graphitic Carbon Support

Theoretical Investigation of the Oxygen Reduction Reaction over Platinum Catalysts Supported by Multi‐Edged Vertically Aligned Carbon Nanofiber for Electrocatalyst Preparation

N,S‐co‐doped FeCo Nanoparticles Supported on Porous Carbon Nanofibers as Efficient and Durable Oxygen Reduction Catalysts

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