An in-situ Raman study of the effect of the support for adsorbed iridium-chelates in catalysing oxygen reduction

Metallophthalocyanine-based molecular materials as catalysts for electrochemical reactions

“…In contrast, for the in-plane iridium in phthalocyanines (D 4h symmetry shown by Raman spectroscopy) only end-on adsorption of oxygen occurs, which leads to the peroxide reduction route. The Raman studies carried out by van Veen and co-workers [417] are consistent with the above observations but not necessarily conclusive. Since the nature of the adsorption of oxygen (side on, four electrons, water final product versus end-on two electrons, peroxide final product) seems to be extremely important in dictating the reduction mechanism, which, once again, is of crucial importance in fuel cells applications, some theoretical studies have been carried out by several authors in an effort to predict the type of interaction of the dioxygen molecule with an active site in a macrocyclic.…”

“…van Veen and co-workers [417] have report that the support affects the O 2 reduction selectivity. They used in situ Raman spectroscopy at adsorbed layers of iridiumoctaethylporphyrin (4(C 2 H 5 )IrP), iridium-tetraphenylporphyrin (4(Ph)IrP) and iridium phthalocyanine (IrPc).…”

“…Carbon supported iridium porphyrins are the only known mono-metal chelates that catalyze the direct four-electron reduction of O 2 in acid [415][416][417][418]. van Veen and co-workers [417] have report that the support affects the O 2 reduction selectivity.…”

Iridium As Catalyst and Cocatalyst for Oxygen Evolution/Reduction in Acidic Polymer Electrolyte Membrane Electrolyzers and Fuel Cells

“…By in situ Raman spectroscopy, it was found that the ORR pathway at adsorbed layers of IrOEP, IrTPP, and IrPc depends on the type of support. 75 With the current density normalized by geometric area, the ORR activity of a series of carbon-supported metal− polythiophene composite (M−PTh/C, M = Ir, Ru, Pd, Co, Fe, Ni, Sn) electrocatalysts was investigated under acidic conditions using rotating disk electrode (RDE) voltammetry. 76 Ir−, Ru−, and Pd−PTh/C showed much more positive ORR onset potentials than the other metal−polythiophene composites.…”

An electrochemical quartz crystal microbalance study of platinum phthalocyanine thin films

“…In contrast to FePc and CoPc precious metal phthalocyanines, such as PtPc, PdPc and IrPc are known to exhibit remarkable thermal stability and to resist oxidation. They have been shown to offer good performance as oxygen reduction electrocatalysts [9][10][11][12]. Under certain treatment regimes 'activated' precious metal phthalocyanine complexes are produced that are more active than FePc or CoPc [13].…”