27,512 research outputs found

    Using history to help refine international business theory: ownership advantages and the eclectic paradigm.

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    In John Dunning’s eclectic paradigm firms need to have ownership, location, and internalisation advantages in order to cross borders and engage in foreign direct investment. By drawing on historical evidence on the evolution of a group of leading marketing-based multinationals in consumer goods, this paper claims that, despite its richness, the eclectic paradigm, and in particular the concept of ‘ownership advantages’, needs to be revised and extended, to take into account different levels of institutional analysis. For the eclectic paradigm to give a rounded view of the internationalising firm it needs to acknowledge the critical importance of firm-specific ownership advantages such as the role of the entrepreneur

    In-situ electrochemical quantification of active sites in Fe-N/C non-precious metal catalysts

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    The economic viability of low temperature fuel cells as clean energy devices is enhanced by the development of inexpensive oxygen reduction reaction catalysts. Heat treated iron and nitrogen containing carbon based materials (Fe–N/C) have shown potential to replace expensive precious metals. Although significant improvements have recently been made, their activity and durability is still unsatisfactory. The further development and a rational design of these materials has stalled due to the lack of an in situ methodology to easily probe and quantify the active site. Here we demonstrate a protocol that allows the quantification of active centres, which operate under acidic conditions, by means of nitrite adsorption followed by reductive stripping, and show direct correlation to the catalytic activity. The method is demonstrated for two differently prepared materials. This approach may allow researchers to easily assess the active site density and turnover frequency of Fe–N/C catalysts

    A catalyst layer optimisation approach using electrochemical impedance spectroscopy for PEM fuel cells operated with pyrolysed transition metal-N-C catalysts

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    AbstractThe effect of the ionomer to carbon (I/C) ratio on the performance of single cell polymer electrolyte fuel cells is investigated for three different types of non-precious metal cathodic catalysts. Polarisation curves as well as impedance spectra are recorded at different potentials in the presence of argon or oxygen at the cathode and hydrogen at the anode. It is found that a optimised ionomer content is a key factor for improving the performance of the catalyst. Non-optimal ionomer loading can be assessed by two different factors from the impedance spectra. Hence this observation could be used as a diagnostic element to determine the ideal ionomer content and distribution in newly developed catalyst-electrodes. An electrode morphology based on the presence of inhomogeneous resistance distribution within the porous structure is suggested to explain the observed phenomena. The back-pressure and relative humidity effect on this feature is also investigated and supports the above hypothesis. We give a simple flowchart to aid optimisation of electrodes with the minimum number of trials
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