Platinum group metal-free electrocatalysts: Effects of synthesis on structure and performance in proton-exchange membrane fuel cell cathodes

Workman, Michael J.; Dzara, Michael J.; Ngo, Chilan; Pylypenko, Svitlana; Serov, Alexey; McKinney, Sam; Gordon, Jonathan; Atanassov, Plamen; Artyushkova, Kateryna

doi:10.1016/j.jpowsour.2017.02.067

Cited by 62 publications

(72 citation statements)

References 43 publications

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“…Further explanation later will shed more light. The surface concentration of iron reported is in good agreement with previous studies of Fe−N−C materials for which both surface and bulk iron composition from EDS was obtained …”

Section: Introductionsupporting

confidence: 91%

Hydrothermal Synthesis of Platinum‐Group‐Metal‐Free Catalysts: Structural Elucidation and Oxygen Reduction Catalysis

et al. 2017

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A hydrothermal approach to generate a platinum-group-metalfree (PGM-free) FeÀNÀC catalyst for the oxygen reduction reaction (ORR) is introduced. The process involves partial carbonization by hydrothermal means followed by thermal treatment to obtain the final catalysts. Detailed X-ray scattering analysis of the glucoseÀimidazole catalysts (termed as GLU-IMID-C catalysts), obtained for the first time with the use of CarbonXS GUI program, reveals the presence of face-centered cubic (FCC) iron nanoparticles embedded in partially graphitic carbon in all catalyst variations. We also report the physical characterization of these catalysts by using X-ray photoelectron spectroscopy, BrunauerÀEmmettÀTeller surface area analysis, and transmission electron microscopy. The electrocatalytic behavior of the catalysts towards oxygen reduction is studied separately in acidic and alkaline electrolytes by rotating ring disk electrode measurements. The catalysts exhibit high ORR activity in acidic (0.5 M H 2 SO 4 ) and alkaline (0.1 M KOH) electrolytes. A precursor structureÀperformance relationship of these catalysts and their performance trends in both electrolytes has been discussed in this work.[a] Dr.

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Section: Introductionsupporting

confidence: 91%

Hydrothermal Synthesis of Platinum‐Group‐Metal‐Free Catalysts: Structural Elucidation and Oxygen Reduction Catalysis

et al. 2017

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“…It is well known that the wide range of materials can demonstrate promising activity for ORR including non-precious metals and their alloys with platinum [1,[7][8][9], metal oxides [10,11], metal nitrides [12], metal oxynitrides [13,14], metal carbides [10,12,15], metalnitrogen-carbon (MNC) electrocatalysts [16][17][18][19], metal dichalcogenides [20,21], and N-and B-doped carbon materials with and without metal doping [22][23][24][25][26][27][28][29][30], etc.…”

Section: Introductionmentioning

confidence: 99%

Oxygen Reduction Reaction Catalyzed by Small Gold Cluster on h-BN/Au(111) Support

2017

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The catalytic activity for the oxygen reduction reaction (ORR) of a hexagonal boron nitride (h-BN) monolayer deposited on a Au(111) surface and decorated by a small planar Au 8 cluster has been studied theoretically using density-functional theory. It is shown that gold nanoparticles (Au-NP) deposited on the h-BN/Au(111) surface can provide catalytically active sites for effective ORR at the perimeter interface with the support. Stabilization of oxygen at the perimeter interface between Au-NP and h-BN/Au(111) support promotes OOH* dissociation opening effective 4electron pathway of ORR with formation of H 2 O. It is suggested that increase in the perimeter interface area between the supported Au-NP and the surface would result in increase of the ORR activity. Such increase in the perimeter interface area can be achieved by decreasing the size of Au-NP. Our calculations demonstrate the principal ability to functionalize inert materials such as stand-alone h-BN monolayer or Au surface for the ORR and open new way to design effective Pt-free catalysts for fuel-cell technology.

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“…As a general behavior, iron-doped carbons (S_GA_Fe and S_GA_FeCu) exhibit better electrocatalytic properties with respect to S_GA_Cu. This could be justified by the presence both of iron species [ 15 ] and of a large amount of N-CNTs characterized by a high electrocatalytic activity towards ORRs [ 42 , 43 , 44 , 45 , 46 ]. This peculiarity of N-CNTs derives from the presence of substitutional nitrogen in their graphene planes, which, disturbing their uniform π-cloud [ 47 ] and increasing the localized density of states at the Fermi level [ 48 ], imparts a n-type dopant activity.…”

Section: Resultsmentioning

confidence: 99%

“…These materials, though very efficient, present some drawbacks, such as costs, availability, and technological problems. Finding cheaper substitutes with similar or better electrocatalytic properties and stability is a challenge for the scientific community [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. Effective candidates are based on metal–nitrogen–carbon catalysts, in which the metal is usually iron or cobalt [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

“…Many studies have been devoted to highlighting the complex nature and chemical environment of catalytic sites [ 12 , 13 , 18 ]. Principal results show that several types of active sites are present on the catalyst surface [ 14 ], and that iron coordination complexes with nitrogen promote ORRs to water [ 15 ]. Moreover, all these active centers are embedded in graphene planes [ 19 ].…”

Section: Introductionmentioning

confidence: 99%

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Synergistic Effects of Active Sites’ Nature and Hydrophilicity on the Oxygen Reduction Reaction Activity of Pt-Free Catalysts

et al. 2018

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This work highlights the importance of the hydrophilicity of a catalyst’s active sites on an oxygen reduction reaction (ORR) through an electrochemical and physico-chemical study on catalysts based on nitrogen-modified carbon doped with different metals (Fe, Cu, and a mixture of them). BET, X-ray Powder Diffraction (XRPD), micro-Raman, X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Scanning Transmission Electron Microscopy (STEM), and hydrophilicity measurements were performed. All synthesized catalysts are characterized not only by a porous structure, with the porosity distribution centered in the mesoporosity range, but also by the presence of carbon nanostructures. In iron-doped materials, these nanostructures are bamboo-like structures typical of nitrogen carbon nanotubes, which are better organized, in a larger amount, and longer than those in the copper-doped material. Electrochemical ORR results highlight that the presence of iron and nitrogen carbon nanotubes is beneficial to the electroactivity of these materials, but also that the hydrophilicity of the active site is an important parameter affecting electrocatalytic properties. The most active material contains a mixture of Fe and Cu.

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Platinum group metal-free electrocatalysts: Effects of synthesis on structure and performance in proton-exchange membrane fuel cell cathodes

Cited by 62 publications

References 43 publications

Hydrothermal Synthesis of Platinum‐Group‐Metal‐Free Catalysts: Structural Elucidation and Oxygen Reduction Catalysis

Hydrothermal Synthesis of Platinum‐Group‐Metal‐Free Catalysts: Structural Elucidation and Oxygen Reduction Catalysis

Oxygen Reduction Reaction Catalyzed by Small Gold Cluster on h-BN/Au(111) Support

Synergistic Effects of Active Sites’ Nature and Hydrophilicity on the Oxygen Reduction Reaction Activity of Pt-Free Catalysts

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