Exploring the Effect of Gold Support on the Oxygen Reduction Reaction Activity of Metal Porphycenes

Abstract

It has been a long‐standing goal to find alternative, cost effective catalysts for oxygen reduction reaction (ORR) in fuel cells. Molecular complexes capable of efficiently catalyzing ORR, when supported on a conducting solid surface could provide interesting hybrid materials combining the best of homogeneous and heterogeneous catalysis. We use density functional theory to study the ORR activity of molecular (unsupported) and gold supported 3d metal (II)‐porphycenes (MPc). All the 3d metal‐porphycenes adsorb strongly on the Au(111) support with negative free energy of formation ranging from 1.0–3.0 eV while solvation lowers the energy of molecular MPc by only 0.5 eV compared to the gas phase. These indicate that the 3d MPc are stable and anchored firmly to the gold surface under ORR conditions. Based on our analysis, the gold support enhances the ORR activity in some of the examined MPc systems. We find that the molecular MnPc and FePc are the best ORR electrocatalysts with theoretical overpotentials of 0.44 V and 0.36 V. This work highlights the important role of the support in preserving/increasing the activity of molecular catalyst.

Enhanced Magnetism through Oxygenation of FePc/Ag(110) Monolayer Phases

“…However, the highly unquenched orbital magnetic moment of FePc when the molecule is not in contact with a metallic surface (mL/mS ≈ 1) 29 , 31 is fully lost in FePc/Ag(110) phases, both in the pristine (or annealed) phases as in the oxidized ones. [1] and [2], as well as curves earlier reported for low-density phases R2 and R2 OX , ref. 16 .…”

“…At room temperature, FePc on Ag(110) selfassembles up to the ML in several ordered phases, all of them characterized by flat-lying molecular overlayers. We detect five FePc phases when increasing the surface density, with occupation densities ranging from 0.421 to 0.527 molecules per nm 2 . Figure 1 summarizes these arrangements by showing their STM topography, LEED pattern, structural model, and matrix notation with respect to the Ag(110) substrate.…”

“…Recently, the spontaneous assembly and the electronic and magnetic properties of FePc have been studied on a variety of substrates: Au(111), − Au(001), Au(100), TiO 2 (110), InAs(100), InSb(100), Cu(110), NaCl/Cu(111), Ag(111), , graphite and graphene/Cu(111), Ni(111) . In particular, FePc/Ag(110) has been intensively investigated to shed light into the self-assembly, interaction mechanisms, structural transformations upon thermal treatments, and its capacity to accommodate small molecules like O 2 .…”

“…. 7c and Fig.S6) and the fitting of the experimental data using Eqs [1]. and[2] allowed us to determine /…”

Electronic Tuning of Cobalt Porphyrins Immobilized on Nitrogen-Doped Graphene for CO2 Reduction

“…The underlying mechanism was not discussed in detail but likely is due to the electronic interaction between the support and CoTPP molecules. Similar interaction has been demonstrated by several studies on the molecular complex with metal support as a model system. − Although significant improvements have been achieved by immobilizing the molecular catalysts onto carbonaceous support, the understanding of the correlation between the electronic structure of the support and the CO 2 electroreduction activity of molecular catalyst has yet to be studied.…”