Orientation study of iron Phthalocyanine (FePc) thin films deposited on silicon and gold surfaces

Singh, Jaspreet; Sharma, Rajendra K.; Goutam, U.K.; Sule, Uday; Gupta, Juhi; Gadkari, S. C.; Rao, P. Nageswara

doi:10.1088/2053-1591/aae49e

Cited by 6 publications

(5 citation statements)

References 24 publications

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“…The FePc/KJ600 catalyst shows three peaks: the first peak at 398.6 eV is labeled N1 in the form of −N�C− and not bonded to the Fe center (Figure S9), the second peak at 399.6 eV is N coordinating with the Fe center (N2), and the last peak at 400.2 eV may correspond to the shake-up satellite at a higher binding energy. 56 After the ORR, the prominent peaks at 398.6 and 399.6 eV shift to 400.5 eV, a position that is assigned to −NH− (N3). 57 This result suggests that after the ORR tests, most of the N species are converted to N3.…”

Section: Structural Evolution During the Orrmentioning

confidence: 99%

Molecular Degradation of Iron Phthalocyanine during the Oxygen Reduction Reaction in Acidic Media

et al. 2022

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Molecular iron phthalocyanine (FePc) possesses an FeN4 active site structure similar to practical pyrolyzed Fe/N/C catalysts for the acidic oxygen reduction reaction (ORR), making it an ideal model system to derive the degradation mechanism of such catalysts. However, the degradation mechanism of FePc during the acidic ORR has been largely unclear to date. Herein, five most likely degradation factors affecting FePc-based ORR activity are individually investigated and compared. The attack by free radicals is found to be the main reason for the instability of FePc. Assisted by the combination of several spectroscopic methods, we successfully identify the degradation products and then propose a full structural evolution of molecular FePc degradation. Finally, high similarity in the decay mechanism between molecular FePc and practical Fe/N/C catalysts was present. This study provides a clear picture of the currently missing degradation mechanism of molecular FePc during acidic ORR, which will assist future investigations on the performance degradation of practical Fe/N/C catalysts.

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Section: Structural Evolution During the Orrmentioning

confidence: 99%

Molecular Degradation of Iron Phthalocyanine during the Oxygen Reduction Reaction in Acidic Media

et al. 2022

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“…4.4.2. Core substitutions of phthalocyanines All COMs discussed so far are intrinsically non-polar and therefore do not offer the possibility to tune the ELA by a permanent molecular dipole moment, whose magnitude and orientation may in uence the vacuum level and thus the ELA [348,386,449,450, [76,166,167,316,348,386,398,449,454,[505][506][507][508][509][510][511][512][513][514][515]. Since only a few adsorption distances have been measured for porphyrins by XSW [388,389], we focus on Pcs.…”

Section: Intermediate Casesmentioning

confidence: 99%

Binding and electronic level alignment of π-conjugated systems on metals

et al. 2020

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We review the binding and energy level alignment of π-conjugated systems on metals, a eld which during the last two decades has seen tremendous progress both in terms of experimental characterization as well as in the depth of theoretical understanding. Precise measurements of vertical adsorption distances and the electronic structure together with ab initio calculations have shown that most of the molecular systems have to be considered as intermediate cases between weak physisorption and strong chemisorption. In this regime, the subtle interplay of different effects such as covalent bonding, charge transfer, electrostatic and van der Waals interactions yields a complex situation with different adsorption mechanisms. In order to establish a better understanding of the binding and the electronic level alignment of π-conjugated molecules on metals, we provide an up-to-date overview of the literature, explain the fundamental concepts as well as the experimental techniques and discuss typical case studies. Thereby, we relate the geometric with the electronic structure in a consistent picture and cover the entire range from weak to strong coupling.

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“…Figure shows the XPS spectra of the as-prepared Fe SAC@G catalyst and the catalysts with different current attenuation rates I ca . As for Figure a, the peak Fe 2p 3/2 of the as-prepared catalyst can be fit into one satellite peak at 712.0 eV and two other peaks, corresponding to the Fe 2+ ion in the Fe–N 4 coordination structure (709.4 eV) , and the Fe 3+ ion in the Fe 3+ –O coordination structure (710.6 eV). The peak Fe 2p 3/2 of the catalyst with I ca = 20% can be deconvoluted into one satellite peak at 713.1 eV and five other peaks, in which the peaks at 709.6, 709.3, 709.0, and 708.3 eV correspond to Fe 2+ ions in Fe–N 4 , Fe–N 3 , Fe–N 2 , and Fe–N, respectively, and the peak at 711.0 eV is referred to the Fe 3+ ion in the Fe 3+ –O coordination structure.…”

Section: Resultsmentioning

confidence: 85%

“…The N 1s core-level spectra of the catalysts are shown in Figure b. The spectrum of the as-prepared catalyst was deconvoluted into two peaks with binding energies of 399.1 and 399.5 eV, characterized as the N atoms in pyridine-N and the N atoms coordinated with Fe 2+ ions. , The spectra of the catalysts with 20% I ca and 70% I ca were deconvoluted into four peaks with binding energies of 399.1, 399.2, 400.5, and 399.5 eV, which can be characterized as the N atoms in pyridine-N, pyrrole-N, graphite-N, and the N atoms coordinated with Fe 2+ ions, respectively. The peak area ratios of the N atoms coordinated with Fe 2+ ions and pyrrole-N for the discharged catalyst with 20% I ca are 90.91 and 9.09%, while those for the discharged catalyst with 70% I ca are 10.42 and 89.58%, respectively.…”

Section: Resultsmentioning

confidence: 99%

Investigations on the ORR Catalytic Performance Attenuation of a 1D Fe Single-Atom Catalyst during the Discharge Process

Yan

Liu

et al. 2022

J. Phys. Chem. C

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The attenuation process of the oxygen reduction reaction (ORR) catalytic performance for Fe SAC@G catalysts under different discharging conditions, including KOH concentrations, solution temperatures, and discharging potentials, was investigated by electrochemical measurements. The ORR catalytic activity attenuation resulting from the change in KOH concentration and temperature becomes apparent in a negative discharging potential range and elevated discharging temperature. In addition, the more negative discharging potential significantly causes the ORR catalytic activity attenuation. Scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy analyses indicate that, with the prolongation of the discharge time, the nanocolumns of the as-prepared catalyst gradually dissolve, while a flowerlike discharge byproduct composed of elements C and N keeps growing on the surface of the catalyst. The weakest Fe−N bonds first break, resulting in the attenuation of the ORR catalytical performance. Then, the weak C−C unit bonds connecting the structural units of the catalysts break, leading to the gradual collapse in the structure of the catalysts. The Fe−N 4 coordination structure gradually transforms into Fe−N 3 , Fe−N 2 , and Fe−N coordination structures. Based on the analyses combined with the density functional theory (DFT) calculations of bond strength, a discharge attenuation mechanism of the structural collapse of the catalyst for the formation of the discharge byproduct with ring structure is proposed.

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Orientation study of iron Phthalocyanine (FePc) thin films deposited on silicon and gold surfaces

Cited by 6 publications

References 24 publications

Molecular Degradation of Iron Phthalocyanine during the Oxygen Reduction Reaction in Acidic Media

Molecular Degradation of Iron Phthalocyanine during the Oxygen Reduction Reaction in Acidic Media

Binding and electronic level alignment of π-conjugated systems on metals

Investigations on the ORR Catalytic Performance Attenuation of a 1D Fe Single-Atom Catalyst during the Discharge Process

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