A ring-disk electrode study of the reduction of oxygen on active carbon in alkaline solution

Appel, M. F.; Appleby, A.J.

doi:10.1016/0013-4686(78)85080-4

Cited by 53 publications

(26 citation statements)

References 17 publications

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“…50 is better than the C 1−x N x samples and comparable to those of the TM-C-N samples. Note that when N is lost from TM x C 1−x−y N y and C 1−x N x samples during heating, it is likely that some porosity, similar to the porosity in activated carbon, may form.…”

Section: Discussionmentioning

confidence: 67%

Final Report - Novel Approach to Non-Precious Metal Catalysts

Atanasoski¹

2007

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This project was directed at reducing the dependence of PEM fuel cell catalysts on precious metals. The primary motivation was to reduce the cost of the fuel cell stack as well as the overall system cost without loss of performance or durability. Platinum is currently the catalyst of choice for both the anode and the cathode. However, the oxygen reduction reaction (ORR) which takes place on the cathode is an inherently slower reaction compared to the hydrogen oxidation reaction (HOR) which takes place on the anode. Therefore, more platinum is needed on the cathode than on the anode to achieve suitable fuel cell performance. As a result, developing a replacement for platinum on the cathode side will have a larger impact on overall stack cost.The drawbacks of using platinum as an ORR catalyst include its price, scarcity, and susceptibility to forming oxides at voltages of interest for efficient fuel cell operation. The price of platinum has more than doubled during the time period between the drafting of the proposal for this project and its completion. The monthly average price in the beginning of 2003 was $620/troy oz and the present price is $1450/troy oz. At these numbers and the 2010 DOE targets of 0.2 g Pt/kW and $30/kW, the cost of fuel cell stack would be over 30% due to platinum. Thus, the specific objectives of the project, as stated in the solicitation, were to produce non-precious metal (NPM) cathode catalysts which reduce dependence on precious metals (especially Pt), perform as well as conventional precious metal catalysts currently in use in MEAs, cost 50% less compared to a target of 0.2 g Pt/peak kW, and demonstrate durability of greater than 2000 hours with less than 10% power degradation. During the term of the project, DOE refined its targets for NPM catalyst activity to encompass volumetric current density. The DOE Multi-Year RD&D Plan (2005) volumetric current density targets for 2010 and 2015 are greater than 130 A/cm 3 and 300 A/cm 3 at 800 mV (IR-free) respectively.The initial approach to achieve these targets was to use vacuum deposition techniques to deposit transition metal, carbon and nitrogen moieties onto 3M's nanostructured thin film (NSTF) catalyst support. While this approach yielded compounds with similar physicochemical characteristics as catalysts reported by others as active for ORR, the activity of these vacuum deposited catalysts was not satisfactory. In order to enhance catalytic activity additional process steps were introduced, the most successful of which was a thermal treatment. To withstand high temperatures (~900 ºC), alternative supports to NSTF were introduced. A variety of carbon fabrics were tested for this purpose. Vacuum deposited materials were used as precursors and physicochemically transformed via thermal treatment to produce substantially better catalytic activity. This activity was further amplified by increasing the surface area of the carbon fabrics which lead to significant gains in fuel cell performance.iii The second synthetic approach was based on 3M...

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Section: Discussionmentioning

confidence: 67%

Final Report - Novel Approach to Non-Precious Metal Catalysts

Atanasoski¹

2007

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“…As the ORR involves four electrons, four protons and a O-O bond cleavage, it has a complex mechanism in acidic [91][92][93], alkaline [88,94,95] and neutral [90] electrolytes at low and moderate temperatures. Depending on the electrode material where the electrochemical oxygen reduction reaction takes place, H 2 O 2 may be generated during the ORR as an intermediate or a final product [96][97][98][99].…”

Section: Oxygen Reduction Reaction Pathwaysmentioning

confidence: 99%

Direct Ethanol Fuel Cell on Carbon Supported Pt Based Nanocatalysts

Almeida

Şahin

Olivi

et al. 2016

Nanostructure Science and Technology

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One of the biggest problems nowadays comes from the progressive increase in the concentration of toxic gases due to combustion of fossil fuels, which represents a large part of the energy consumed by the society. The greenhouse gas emissions, especially in large urban centers, reach every year increasingly levels. Besides the large industries, urban transport is another main factor responsible for pollution.The need for cleaner energy sources and converter systems that combine high efficiency and reduction of environmental impacts has attracted increasing interest from the scientific community. In this context, fuel cells, system capable of converting chemical energy into electrical energy, are receiving special attention mainly due to its ability to generate electricity efficiently and not aggressive to the environment. The versatility of such systems is the feasible use of various fuels, efficient energy conversion, silent operation, and high applicability. These make this system an attractive technology for a "clean" future [1].

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“…Yang et al [37] showed that Pd/C catalysts in alkaline had high activity for ORR, and that the carbon support itself is active for the two-electron reduction of O 2 to peroxide (which can then migrate to the Pd particles for subsequent twoelectron reduction to water). It is shown that all carbon materials have some ORR activity in alkaline solution (but none in acid), normally for the twoelectron reduction to peroxide, although some oxidized carbon surfaces can complete the serial reduction to water at higher overpotentials [24,[38][39][40].…”

Section: The Orr Mechanismmentioning

confidence: 99%

Alkaline Anion Exchange Membrane Fuel Cells

Jervis¹,

Brett²

2014

Materials for Low‐Temperature Fuel Cells

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Fuel cells represent a potentially integral technology in a greener electricitybased energy economy. Converting chemical energy directly into electricity with no moving parts and no particulate or greenhouse gas emissions at point of operation, they can offer higher efficiencies than combustion and greater energy storage and reduced "charge" times compared with batteries. While they retain few of the disadvantages of existing electricity generation technologies, a major barrier to commercialization and widespread use at present is cost. The key working part of a fuel cell, the membrane electrode assembly (MEA), comprises a catalyst, usually containing platinum, and an ionic polymer membrane, both of which contribute significantly to the overall cost of a fuel cell. This chapter will concentrate on the potential for alkaline anion exchange membrane (AAEM) fuel cells to provide a route to reduced costs and help realize commercial ubiquity of fuel cells in various energy sectors. We will first discuss the basic principles of the more common acidic PEM fuel cells and the thermodynamics and kinetics of the electrochemical reactions governing their operation, before explaining the key differences in AAEM fuel cells and how they might provide an advantage over the more established technology.This basic idea of the fuel cell goes back to as far as 1839 when Swanseaborn physicist Sir William Gove realized that reverse electrolysis of water was possible. However, development from this concept was slow and it was not until the 1960s and the Apollo Space Programme that fuel cells became practicable, in the form of aqueous alkaline electrolyte fuel cells. Aqueous electrolyte-based fuel cells have many disadvantages for portability causing recent focus to shift toward solid electrolytes, in particular toward polymer electrolyte membrane (PEM) fuel cells. These employ an ionomer, which is a polymer containing an ionic functional group in the monomer, as the electrolyte in order to allow hydrogen ion transport through a nonaqueous medium. Recent improvements in membrane technology, and in particular the performance of the industry standard Nafion membranes, have made PEM fuel cells a major focus of research. The alkaline 3 Materials for Low-Temperature Fuel Cells, First Edition. Edited

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A ring-disk electrode study of the reduction of oxygen on active carbon in alkaline solution

Cited by 53 publications

References 17 publications

Final Report - Novel Approach to Non-Precious Metal Catalysts

Final Report - Novel Approach to Non-Precious Metal Catalysts

Direct Ethanol Fuel Cell on Carbon Supported Pt Based Nanocatalysts

Alkaline Anion Exchange Membrane Fuel Cells

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