Oxygen reduction on platinum in aqueous sulphuric acid in the presence of ammonium

Halseid, Rune; Bystroň, Tomáš; Tunold, R.

doi:10.1016/j.electacta.2005.08.011

Cited by 41 publications

(35 citation statements)

References 18 publications

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“…A small shoulder in front of the Pt oxide formation region was also observed and is related to the oxidation of ammonium to form nitrogen, which probably involves several adsorbed intermediates like NH x ,ads, N 2 H y ,ads, and N 2 ,ads. Formation of NO has also been observed in CV scans at potentials higher than those used in the ORR measurements [35]. Fig.…”

Section: 5mentioning

confidence: 85%

“…As estimated based on the hydrogen desorption region on the CV curve, the ECSA decreased slightly with increasing ammonium concentration, confirming the notion of active site reduction by the adsorption of NH 4 þ or NH 3 on Pt through the blocking effect, which causes changes in the kinetic parameters or the reaction mechanisms of the ORR and is at least partially accountable for the increased performance decay and degradation. Halseid et al [35] have suggested that the formation of more stable Pt oxides and possibly also nitrogeneoxygen species on the Pt surface are responsible for the effect. The pronounced effect of ammonium on the most strongly adsorbed hydrogen is believed also to be due to an interaction between ammonium and hydrogen adsorption on the surface.…”

Section: 5mentioning

confidence: 98%

“…To better understand the poisoning and recovery mechanisms of ammonium in PEMFCs, Halseid et al [34,35] studied the effect of ammonium ions on the oxygen reduction reaction (ORR) using a polycrystalline rotating disk Pt electrode in aqueous sulfuric acid, and found that even in moderate concentrations (2 ppm), ammonium significantly affected the ORR on Pt. Oxidation of ammonium on polycrystalline Pt has also been studied in perchloric and sulfuric acid solutions at room temperature [33].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Diagnosis of contamination introduced by ammonia at the cathode in a polymer electrolyte membrane fuel cell

Yuan

et al. 2012

International Journal of Hydrogen Energy

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Section: 5mentioning

confidence: 85%

Section: 5mentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Diagnosis of contamination introduced by ammonia at the cathode in a polymer electrolyte membrane fuel cell

Yuan

et al. 2012

International Journal of Hydrogen Energy

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“…The Langmuir and Temkin adsorption conditions for oxygen species are reflected by the linear appearance of the high and low current density regions of the Tafel plot respectively. The Tafel slope associated with Langmuir and Temkin adsorption conditions is −0.12 and −0.06 V dec −1 respectively [44], but different Tafel slope values have been documented for Pt/C catalyst in alkaline condition [45]. Oxygen adsorption on Pt/C surface can adopt the bridge side-on and bridge end-on adsorbate configurations [46].…”

Section: Rrde Voltammetry Analysismentioning

confidence: 99%

Electrocatalytic activity of nitrogen doped carbon nanotubes with different morphologies for oxygen reduction reaction

Chen

Higgins

Chen

2010

Electrochimica Acta

104

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“…As discussed above, the NH 3 could react in a major way with the protons in the ionomer, reducing proton conductivity in the catalyst layer [27,54]. The gradient in the double layer might also be influenced by the formation of 4 NH in the catalyst layer, which affects the symmetry factor for oxygen adsorption [27,55].…”

Section: Nh 3 and H 2 S Contaminationmentioning

confidence: 96%

Catalyst Contamination in PEM Fuel Cells

Li¹,

Song²,

Zhang³

et al.

PEM Fuel Cell Electrocatalysts and Catalyst Layers

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The effects of impurities on fuel cells, often referred to as fuel cell contamination, is one of the most important issues in fuel cell operation and applications. Contamination is closely associated with proton exchange membrane fuel cell (PEMFC) durability and stability, both of which are important factors in the development and commercialization of PEMFC technology. Studies have identified that the membrane electrode assembly (MEA), the heart of the PEMFC, is the fuel cell component most affected by contamination. Impurities in the air and fuel streams damage the MEA by affecting both the anode and cathode catalyst layers (CLs), the gas diffusion layers (GDLs), as well as the proton exchange membrane (PEM), causing MEA performance degradation or even fuel cell failure. In general, PEMFC contamination effects can be categorized into three major types: (1) kinetic losses caused by the poisoning of both anode and cathode catalyst sites or a decrease in the catalyst activity; (2) ohmic losses due to an increase in the resistance of membrane and ionomer, caused by alteration of the proton transportation path; and (3) mass transfer losses due to changes in structure and in the ratio between the hydrophobicity and hydrophilicity of CLs, GDLs, and the PEM. Among those effects, the most significant is the kinetic effect of the anode and cathode electrocatalysts. This chapter presents PEMFC contamination with a focus on the anode and cathode catalyst layers. Catalyst contamination mechanisms, experimental results, modeling, as well as mitigation strategies are also covered in detail. For further information, such as contamination effects on other parts of PEMFCs, the reader is referred to a recent review paper [1]. Anode Catalyst Layer ContaminationThe dominant type of PEMFC is the hydrogen/oxygen fuel cell, in which the anode is fed by hydrogen and the cathode is fed by oxygen or air. In this section, we will focus our attention on anode catalyst contamination caused by impurities in the hydrogen stream.

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Oxygen reduction on platinum in aqueous sulphuric acid in the presence of ammonium

Cited by 41 publications

References 18 publications

Diagnosis of contamination introduced by ammonia at the cathode in a polymer electrolyte membrane fuel cell

Diagnosis of contamination introduced by ammonia at the cathode in a polymer electrolyte membrane fuel cell

Electrocatalytic activity of nitrogen doped carbon nanotubes with different morphologies for oxygen reduction reaction

Catalyst Contamination in PEM Fuel Cells

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