Immobilisation of iron ions on nafion® and its applicability to the photo-fenton method

Degradation mechanism study of perfluorinated proton exchange membrane under fuel cell operating conditions

“…It has been pointed out that the metal ion and H 2 O 2 concentrations necessary for the occurrence of hydroxyl radical can be very low (<10-25 mg/L H 2 O 2 and 1 part Fe per 5-25 parts of H 2 O 2 (wt/wt) [38]) Fig. 5b shows our cathode durability test arrangement.…”

“…From the perspective of peroxide radical attack of the membrane, hydroxy ( • OH) and hydroperoxy ( • OOH) radicals are the most likely initiators of membrane chemical decomposition [13] as they are some of the most reactive chemical species known [20][21][22]. Radical-initiated attack leads to the breakage of perfluorocarbon backbone in Nafion membranes and sulphonate groups which directly affect mechanical strength and proton conductivity of the membranes [23], leading to increase in total cell resistance and a loss in net power output.…”

Fe(III)-loaded collagen fiber as a heterogeneous catalyst for the photo-assisted decomposition of Malachite Green

“…Iron salts are usually employed as the catalyst in a homogeneous system of Fenton reaction, however, the Fe(III) directly added into reaction solution is hard to be recovered and may cause secondary pollution [5]. This drawback can be avoided by using heterogeneous catalysts where Fe(III) are often immobilized onto some supporting matrices including inorganic and organic compounds, such as zeolite [5], clay [6][7][8], oxide [9], resin [2,10] and Nafion membrane [11,12]. In addition, some natural and renewable biomasses like chitosan [13], cellulose [14] and silk [15] are also used as the matrices to prepare heterogeneous catalysts.…”

Durability of PEM fuel cell cathode in the presence of Fe3+ and Al3+

“…This sudden death is likely related to Fenton's reactions, which produce hydroxyl radicals and subsequently cause membrane failure. First, Fe 3+ ions immobilized on Nafion ® membrane in the presence of peroxide can produce radicals by reduction into Fe 2+ through a modified Fenton's reaction [20,27]:…”

“…The hydroxyl radical is considered one of the most reactive chemical species known and can in the long term degrade Nafion ® polymer chains, resulting in fluoride loss and reduced conductivity [27]. Hydroxyl radicals can also damage the membrane by attacking the H-containing terminal bonds present in the polymer (i.e., Habstraction) [5,28], which can result in the formation of membrane pinholes.…”