Oxygen Reduction Reaction and Peroxide Generation on Ir, Rh, and their Selenides – A Comparison with Pt and RuSe

Neergat, Manoj; Gunasekar, V.; Singh, Ramesh Kumar

doi:10.1149/1.3604744

Cited by 31 publications

(28 citation statements)

References 53 publications

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“…Presumably the partial coverage of Ir particles with Se occurs which causes changes in its surface properties. Similar results were observed previously in the literature (17)(18)(19).…”

Section: Characterization Of Catalystssupporting

confidence: 93%

Synthesis and Characterization of New Non-Platinum Electrocatalysts for Oxygen Reduction

et al. 2013

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A new group of carbon-supported ruthenium-and iridium-based electrocatalysts for oxygen reduction reaction (ORR) was synthesized, using RuCl 3 or IrCl 3 and selenourea (as precursor of both Se and N). The heat treated catalysts (later abbreviated as RuSeN/C and IrSeN/C) were subjected to physical characterization, like X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Studies revealed changes in surface properties of Ru-and Ir-based catalysts. Catalytic performances of obtained catalysts were evaluated using Rotating Ring Disk Electrode (RRDE) in acid solution. The ORR activity and hydrogen peroxide generation on designed selenides were dependent on the ratio of metal and selenourea used in precursor blend and were separately characteristic for ruthenium and iridium. While RuSeN/C exhibited high ethanol tolerance, the ORR activity of IrSeN/C in the presence of ethanol depended on the amount of selenourea. CoSeN/C and FeSeN/C were also prepared and characterized as low-cost alternative catalysts.

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“…Presumably the partial coverage of Ir particles with Se occurs which causes changes in its surface properties. Similar results were observed previously in the literature (17)(18)(19).…”

Section: Characterization Of Catalystssupporting

confidence: 93%

Synthesis and Characterization of New Non-Platinum Electrocatalysts for Oxygen Reduction

et al. 2013

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“…6c). [8][9][10][64][65][66][67] The peroxide generation features with Pt have been investigated by various groups. 63 Soon after the electrochemical reduction, when the Pd nanoparticles are exposed to atmospheric oxygen, a passive oxygen coverage is formed at the surface.…”

Section: Resultsmentioning

confidence: 99%

“…1 Thus, ORR has been investigated on Pt well-defined single-crystal surfaces and polycrystalline nanoparticles in both acidic and alkaline media. [8][9][10][11][12][13][14] The H 2 O 2 generation features depend on the active site density of the electrode, catalyst layer thickness and the potential dependent ORR mechanism. Moreover, the H 2 O 2 that is generated can lead to reduced membrane durability.…”

Section: Introductionmentioning

confidence: 99%

The role of surface oxygenated-species and adsorbed hydrogen in the oxygen reduction reaction (ORR) mechanism and product selectivity on Pd-based catalysts in acid media

Rahul

Singh

Bera

et al. 2015

Phys. Chem. Chem. Phys.

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Oxygen reduction reaction (ORR) is investigated on bulk PdO-based catalysts (oxides of Pd and Pd3Co) in oxygen-saturated 0.1 M HClO4 to establish the role of surface oxides and adsorbed hydrogen in the activity and product selectivity (H2O/H2O2). The initial voltammetric features suggest that the oxides are inactive toward ORR. The evolution of the ORR voltammograms and potential-dependent H2O2 generation features on the PdO catalyst suggest gradual and parallel in situ reduction of the bulk PdO phase below ∼0.4 V in the hydrogen underpotential deposition (Hupd) region; the reduction of the bulk PdO catalyst is confirmed from the X-ray photoelectron spectra (XPS) and X-ray diffraction (XRD) patterns. The potential-dependent H2O2 generation features originate due to the presence of surface oxides and adsorbed hydrogen; this is further confirmed using halide ions (Cl(-) and Br(-)) and peroxide as the external impurities.

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“…These include, in addition to Pt-based materials, chalcogenides, Pd alloys, and non-precious metal catalysts. [4][5][6][42][43][44][45][46][47] TF-RDE/rotating ring disk electrodes (RRDE) are popular in the characterization of these new catalyst formulations. Usually, this is done in aqueous electrolytes (0.1 M KOH, 0.1 M HClO 4 or 0.5 M H 2 SO 4 ) or non-aqueous electrolytes (lithium bis(trifluoromethylsulfonyl) imide (LiTFSI) in diglyme) using DC methods.…”

mentioning

confidence: 99%

Electrochemical Impedance Spectroscopy of Oxygen Reduction Reaction (ORR) in a Rotating Disk Electrode Configuration: Effect of Ionomer Content and Carbon-Support

Singh

Devivaraprasad

Kar

et al. 2015

J. Electrochem. Soc.

168

112

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Oxygen reduction reaction (ORR) in acidic media is investigated at various potentials in a thin-film rotating disk electrode (TF-RDE) configuration using electrochemical impedance spectroscopy (EIS). The ionomer-free and ionomer-containing thin-film catalyst layers are composed of Pt black and carbon-supported Pt catalysts of different metal loadings (5 and 20 wt%). The simplest EI spectrum consisting of an arc or a semi-circle is obtained at high potentials with ionomer-free Pt catalyst layers. The most complex spectrum consisting of a high frequency (HF) arc and two semi-circles is observed in the mixed diffusion-controlled region of the ionomer-containing catalyst layer with high loading of carbon-supported Pt. The nature of the EI spectrum is decided by the constituents of the thin-film catalyst layer and by the operating potential. The evolution of the EI spectra with ionomer and carbon contents is underlined. The effect of rotation rate (rpm) of the electrode on the impedance spectrum is also investigated. A series of equivalent circuits is required to completely describe the EI spectra of ORR. The kinetic parameters and the electrochemical surface area of the catalysts are derived from the impedance spectrum. Oxygen reduction reaction (ORR) is one of the most important reactions at the cathode side in low-temperature fuel cells (e.g., polymer electrolyte fuel cells (PEFCs) and direct methanol fuel cells (DMFCs)) and metal-air batteries.1-14 Because of the sluggish ORR kinetics and the stability issues of the catalyst in the electrochemical environment, expensive precious metal catalysts are often used in these electrochemical devices to catalyze the ORR. 15 Conventionally, the performance of the catalyst is evaluated in an operating fuel cell mode using the DC methods. [16][17][18] The information gathered from a DC analysis usually provides the sum of various polarizations of the electrode, which is difficult to separate into individual contributions. 19 On the other hand, electrochemical impedance spectroscopy (EIS), one of the AC methods, is a sensitive tool to investigate electrode-electrolyte interface and it allows the simultaneous resolution of various charge-transfer and mass-transfer processes (kinetic, ohmic, and diffusion). It involves a small sinusoidal electrical perturbation around a steady-state value and measures the impedance along with the phase angle. However, the interpretation of the EI spectra is difficult. Often, simple fitting models based on equivalent circuit analogues and physical models are used to extract the parameters those represent the underlying cell processes. [20][21][22][23][24][25][26] Springer et al. proposed the theoretical impedance spectrum of ORR on porous gas-diffusion electrode using the flooded-agglomerate electrode model in series with a thin electrolyte film. 20,25 The model predicted by Raistrick shows three semi-circles in the spectrum attributed to the charge-transfer process (ORR); agglomerate diffusion (depletion of the oxygen concentration in the pores...

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Oxygen Reduction Reaction and Peroxide Generation on Ir, Rh, and their Selenides – A Comparison with Pt and RuSe

Cited by 31 publications

References 53 publications

Synthesis and Characterization of New Non-Platinum Electrocatalysts for Oxygen Reduction

Synthesis and Characterization of New Non-Platinum Electrocatalysts for Oxygen Reduction

The role of surface oxygenated-species and adsorbed hydrogen in the oxygen reduction reaction (ORR) mechanism and product selectivity on Pd-based catalysts in acid media

Electrochemical Impedance Spectroscopy of Oxygen Reduction Reaction (ORR) in a Rotating Disk Electrode Configuration: Effect of Ionomer Content and Carbon-Support

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