Semi-empirical evaluation of PEMFC electro-catalytic activity

Nanostructured bimetallic alloys prepared via mechanochemical synthesis as PEMFC electrocatalysts for automotive applications

“…We verified the above supposition by analysing the previous data with an electrochemically oriented mathematical model described elsewhere [20]. a, b, c, d lines in Fig.…”

Ordered Mesoporous Carbons as Catalyst Support for PEM Fuel Cells

“…The beneficial effect of Nafion ® increase was experimentally observed; its explanation requires further investigation. For a better evaluation of the MEAs performance, the polarisation curves were analysed by the semi-empirical model previously reported [5]. The main features of this approach are: (i) the use of complete Butler-Volmer equations for both the cathode and the anode, instead of Tafel approximation, (ii) the evaluation of the open circuit voltage as a mixed potential by assuming an arbitrary oxidation current at the cathode, (iii) an expression of the ohmic resistance as a function of current intensity RI R 0 1 aI n , where the parameters a and n are obtained by fitting; by this empirical correction of the ohmic resistance, we could account for phenomena requiring a more sophisticated modelling, such as the increase of membrane resistance with current due to partial de-hydration on the anodic side, or non-ohmic effects due to the porous 3D nature of the electrodes (mass transfer processes).…”

“…Namely: The analysis of the polarisation curves provides the parameters which can be used for the evaluation of the MEA performance: the exchange current density for ORR, i oc ; the exchange current density for HOR, i oa ; the Tafel slope for ORR b O 2 or the corresponding value of the charge transfer coefficient a cat (b À2:03RT=a cat F); the ohmic resistance R o ; the average resistance over the current density range, R m (for a discussion of this point, see ref. [5]); a parameter for the evaluation of the catalyst activity for ORR, defined as the current density at an overpotential of 0.3 V, i g0:3 . The results of the computation for the different tested MEAs, which differ for the cathode composition and structure, are shown in Table 1.…”

Performance analysis of Fe–N–C catalyst for DMFC cathodes: Effect of water saturation in the cathodic catalyst layer

“…This good stability can be attributed mainly to pyridinic and pyrrolic nitrogen like fixation [89]. (30,60,90, and 110 C), and pure fully humidified oxygen flow. The anode (PtRu black) and cathode catalyst (FeeNeC) loadings were maintained at 2.5 mg cm À2 for all tests.…”