ABSTRACT A biomimetic oxidation catalyst, cobalt porphyrin with thiol linkers, was chemically con... more ABSTRACT A biomimetic oxidation catalyst, cobalt porphyrin with thiol linkers, was chemically conjugated to silica particles and utilized in the oxidation of hydroquinone to benzoquinone. The cobalt porphyrin/silica particle catalyst was characterized with Inductively Coupled Plasma (ICP) and X-ray Photoelectron Spectroscopy (XPS). The catalytic performance of the cobalt porphyrin molecules was compared to previous results for the same catalyst grafted to a gold surface and on silicon wafers. The measured catalytic activity, after background correction, was 100 times higher than that of its homogeneous counterpart, 10 times higher than that on a silicon wafer, and almost the same as that on a gold surface. The turnover frequency rates after 400 h are still comparable with initial rates reported for homogeneous porphyrins and salophens, whereas the use of particles as support increases the active surface area, which removes the limitations for scale-up associated with the previously used silicon wafers and gold surfaces.
With the aim of extending the usefulness of an existing biomimetic catalytic system, cobalt porph... more With the aim of extending the usefulness of an existing biomimetic catalytic system, cobalt porphyrin catalytic units with thiol linkers were heterogenized via chemical grafting to silicon wafers and utilized for the catalytic oxidation of hydroquinone to p-benzoquinone. Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were used to analyze the morphology and composition of the heterogeneous catalyst. The results of the catalytic oxidation of hydroquinone obtained with porphyrins grafted on silicon were compared with those obtained earlier with the same catalyst in homogeneous phase and immobilized on gold. It was found that the catalysis could run over 400 h, without showing any sign of deactivation. The measured catalytic activity is at least 10 times higher than that measured under homogeneous conditions, but also 10 times lower than that observed with the catalytic unit immobilized on gold. The reasons of this discrepancy are discussed in term of substrate influence and overlayer organization. The silicon-immobilized catalyst has potential as an advanced functional material with applications in oxidative heterogeneous catalysis of organic reactions, as it combines long-term relatively high activity with low cost.
The remarkable excitonic effects in low dimensional materials in connection to large binding ener... more The remarkable excitonic effects in low dimensional materials in connection to large binding energies of excitons are of great importance for research and technological applications such as in solar energy and quantum information processing as well as for fundamental investigations. In this study, the unique electronic and excitonic properties of the two dimensional carbon network biphenylene carbon were investigated with GW approach and the Bethe-Salpeter equation accounting for electron correlation effects and electron-hole interactions, respectively. Biphenylene carbon exhibits characteristic features including bright and dark excitons populating the optical gap of 0.52 eV and exciton binding energies of 530 meV as well as a technologically relevant intrinsic band gap of 1.05 eV. Biphenylene carbon’s excitonic features, possibly tuned, suggest possible applications in the field of solar energy and quantum information technology in the future.
Negative-bias-stress and relaxation experiments on hydrogenated amorphous silicon/amorphous silic... more Negative-bias-stress and relaxation experiments on hydrogenated amorphous silicon/amorphous silicon dioxide (a-SiO2) thin-film transistors show that the predominant instability mechanism is charge trapping in the gate insulator. The charge injection mechanism can be related to the presence of a defected region in the first 2–3 nm of the gate insulator. A possible cause of such a region could be the hydrogen-induced
Japanese Journal of Applied Physics Vol. 29, No. 12, December, 1990, pp. L2357-L2359 Pd-Gate a-Si... more Japanese Journal of Applied Physics Vol. 29, No. 12, December, 1990, pp. L2357-L2359 Pd-Gate a-Si:H Thin-Film Transistors as Hydrogen Sensors Luigi Mariucci, Alessandro Pecora*, Carla Puglia, Carlo Reità**, Giovanni Petrocco and Guglielmo Fortunato Istituto ...
... a, Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala, Sweden. b, Max-lab, ... more ... a, Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala, Sweden. b, Max-lab, University of Lund, Box 118, S-221 00 Lund, Sweden. ... The XAS measurements were performed at Beam-line I511 [19] at the MAX-lab synchrotron radiation facility in Lund, Sweden. ...
Zinc phthalocyanine (ZnPc) adsorbed on the InSb(001)-c(8×2) surface has been studied by scanning ... more Zinc phthalocyanine (ZnPc) adsorbed on the InSb(001)-c(8×2) surface has been studied by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). Coverages from sub-monolayer to monolayer (ML) have been investigated. The molecules form ordered structures on the reconstructed rows of the surface with the molecular plane parallel to the surface. A change in the electronic structure between the sub-ML and
The origin of one-and two-step behavior of core-hole decay processes is identified in connection ... more The origin of one-and two-step behavior of core-hole decay processes is identified in connection with high resolution autoionization spectra for Ar/Pt (111). The spectra simultaneously show features of the two types (resonant Raman vs Auger-like behavior). ...
Photoelectron spectroscopy data from BiâSrâCa{sub 1-x}YâCuâO{sub 8+δ} single crystals, for x=0, ... more Photoelectron spectroscopy data from BiâSrâCa{sub 1-x}YâCuâO{sub 8+δ} single crystals, for x=0, 0.16, and 0.55, are presented. It is shown that there are core level shifts related to the opening of a pseudogap and that similar shifts are observed at the opening of the superconducting gap in optimally doped samples. This result is in agreement with pair formation above T{sub C}
The electronic structure of a vapor-sublimated thin film of metal-free phthalocyanine (H2Pc) is s... more The electronic structure of a vapor-sublimated thin film of metal-free phthalocyanine (H2Pc) is studied experimentally and theoretically. An atom-specific picture of the occupied and unoccupied electronic states is obtained using x-ray-absorption spectroscopy (XAS), core- and valence-level x-ray photoelectron spectroscopy (XPS), and density-functional theory (DFT) calculations. The DFT calculations allow for an identification of the contributions from individual nitrogen atoms to the experimental N1s XAS and valence XPS spectra. This comprehensive study of metal-free phthalocyanine is relevant for the application of such molecules in molecular electronics and provides a solid foundation for identifying modifications in the electronic structure induced by various substituent groups.
ABSTRACT A biomimetic oxidation catalyst, cobalt porphyrin with thiol linkers, was chemically con... more ABSTRACT A biomimetic oxidation catalyst, cobalt porphyrin with thiol linkers, was chemically conjugated to silica particles and utilized in the oxidation of hydroquinone to benzoquinone. The cobalt porphyrin/silica particle catalyst was characterized with Inductively Coupled Plasma (ICP) and X-ray Photoelectron Spectroscopy (XPS). The catalytic performance of the cobalt porphyrin molecules was compared to previous results for the same catalyst grafted to a gold surface and on silicon wafers. The measured catalytic activity, after background correction, was 100 times higher than that of its homogeneous counterpart, 10 times higher than that on a silicon wafer, and almost the same as that on a gold surface. The turnover frequency rates after 400 h are still comparable with initial rates reported for homogeneous porphyrins and salophens, whereas the use of particles as support increases the active surface area, which removes the limitations for scale-up associated with the previously used silicon wafers and gold surfaces.
With the aim of extending the usefulness of an existing biomimetic catalytic system, cobalt porph... more With the aim of extending the usefulness of an existing biomimetic catalytic system, cobalt porphyrin catalytic units with thiol linkers were heterogenized via chemical grafting to silicon wafers and utilized for the catalytic oxidation of hydroquinone to p-benzoquinone. Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were used to analyze the morphology and composition of the heterogeneous catalyst. The results of the catalytic oxidation of hydroquinone obtained with porphyrins grafted on silicon were compared with those obtained earlier with the same catalyst in homogeneous phase and immobilized on gold. It was found that the catalysis could run over 400 h, without showing any sign of deactivation. The measured catalytic activity is at least 10 times higher than that measured under homogeneous conditions, but also 10 times lower than that observed with the catalytic unit immobilized on gold. The reasons of this discrepancy are discussed in term of substrate influence and overlayer organization. The silicon-immobilized catalyst has potential as an advanced functional material with applications in oxidative heterogeneous catalysis of organic reactions, as it combines long-term relatively high activity with low cost.
The remarkable excitonic effects in low dimensional materials in connection to large binding ener... more The remarkable excitonic effects in low dimensional materials in connection to large binding energies of excitons are of great importance for research and technological applications such as in solar energy and quantum information processing as well as for fundamental investigations. In this study, the unique electronic and excitonic properties of the two dimensional carbon network biphenylene carbon were investigated with GW approach and the Bethe-Salpeter equation accounting for electron correlation effects and electron-hole interactions, respectively. Biphenylene carbon exhibits characteristic features including bright and dark excitons populating the optical gap of 0.52 eV and exciton binding energies of 530 meV as well as a technologically relevant intrinsic band gap of 1.05 eV. Biphenylene carbon’s excitonic features, possibly tuned, suggest possible applications in the field of solar energy and quantum information technology in the future.
Negative-bias-stress and relaxation experiments on hydrogenated amorphous silicon/amorphous silic... more Negative-bias-stress and relaxation experiments on hydrogenated amorphous silicon/amorphous silicon dioxide (a-SiO2) thin-film transistors show that the predominant instability mechanism is charge trapping in the gate insulator. The charge injection mechanism can be related to the presence of a defected region in the first 2–3 nm of the gate insulator. A possible cause of such a region could be the hydrogen-induced
Japanese Journal of Applied Physics Vol. 29, No. 12, December, 1990, pp. L2357-L2359 Pd-Gate a-Si... more Japanese Journal of Applied Physics Vol. 29, No. 12, December, 1990, pp. L2357-L2359 Pd-Gate a-Si:H Thin-Film Transistors as Hydrogen Sensors Luigi Mariucci, Alessandro Pecora*, Carla Puglia, Carlo Reità**, Giovanni Petrocco and Guglielmo Fortunato Istituto ...
... a, Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala, Sweden. b, Max-lab, ... more ... a, Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala, Sweden. b, Max-lab, University of Lund, Box 118, S-221 00 Lund, Sweden. ... The XAS measurements were performed at Beam-line I511 [19] at the MAX-lab synchrotron radiation facility in Lund, Sweden. ...
Zinc phthalocyanine (ZnPc) adsorbed on the InSb(001)-c(8×2) surface has been studied by scanning ... more Zinc phthalocyanine (ZnPc) adsorbed on the InSb(001)-c(8×2) surface has been studied by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). Coverages from sub-monolayer to monolayer (ML) have been investigated. The molecules form ordered structures on the reconstructed rows of the surface with the molecular plane parallel to the surface. A change in the electronic structure between the sub-ML and
The origin of one-and two-step behavior of core-hole decay processes is identified in connection ... more The origin of one-and two-step behavior of core-hole decay processes is identified in connection with high resolution autoionization spectra for Ar/Pt (111). The spectra simultaneously show features of the two types (resonant Raman vs Auger-like behavior). ...
Photoelectron spectroscopy data from BiâSrâCa{sub 1-x}YâCuâO{sub 8+δ} single crystals, for x=0, ... more Photoelectron spectroscopy data from BiâSrâCa{sub 1-x}YâCuâO{sub 8+δ} single crystals, for x=0, 0.16, and 0.55, are presented. It is shown that there are core level shifts related to the opening of a pseudogap and that similar shifts are observed at the opening of the superconducting gap in optimally doped samples. This result is in agreement with pair formation above T{sub C}
The electronic structure of a vapor-sublimated thin film of metal-free phthalocyanine (H2Pc) is s... more The electronic structure of a vapor-sublimated thin film of metal-free phthalocyanine (H2Pc) is studied experimentally and theoretically. An atom-specific picture of the occupied and unoccupied electronic states is obtained using x-ray-absorption spectroscopy (XAS), core- and valence-level x-ray photoelectron spectroscopy (XPS), and density-functional theory (DFT) calculations. The DFT calculations allow for an identification of the contributions from individual nitrogen atoms to the experimental N1s XAS and valence XPS spectra. This comprehensive study of metal-free phthalocyanine is relevant for the application of such molecules in molecular electronics and provides a solid foundation for identifying modifications in the electronic structure induced by various substituent groups.
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