Daniele Pontiroli | Università degli Studi di Parma (Italy) (original) (raw)

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Papers by Daniele Pontiroli

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Materials Research Bulletin

Abstract The addition of transition metals to alkali intercalated fullerides proved to enhance th... more Abstract The addition of transition metals to alkali intercalated fullerides proved to enhance their already good hydrogen absorption properties. Herein we present a study based on two different synthetic strategies, allowing the addition of nickel as aggregates with different size to the lithium fulleride Li6C60: the former is based on the metathesis of nickel chloride, while the latter on the thermal decomposition of nickel carbonyl clusters. The hydrogen-storage properties of the obtained materials have been investigated with manometric and calorimetric measurements, which indicated a clear enhancement of the final absorption value and kinetics with respect to pristine Li6C60, as a consequence of nickel surface catalytic activity towards hydrogen molecules dissociation. We found up to 10 % increase of the total H2 weight % absorbed (5.5 wt% H2) in presence of Ni aggregates. Furthermore, the control of the transition metal particles size distribution allowed reducing the hydrogen desorption enthalpy of the systems.

International Journal of Hydrogen Energy

Abstract Surface decoration of graphene-based nanostructures with metals has been predicted to be... more Abstract Surface decoration of graphene-based nanostructures with metals has been predicted to be an efficient way towards the development of resistant catalysts and novel materials for energy applications, such as hydrogen production and storage. We report on an extensive neutron scattering study of a defective graphene-based material decorated with nickel nanoparticles, obtained via the chemical decoration of thermally exfoliated graphite oxide. The combination of neutron diffraction and inelastic neutron scattering measurements has been used to characterize the low-dimensional carbon backbone and the presence of the nickel nanoparticles, organized at the nanometer scale on the graphene plane. The structural features of this system, along with the nickel capability of dissociating the hydrogen molecule upon hydrogen treatment, are herein discussed.

Physical chemistry chemical physics : PCCP, Jan 23, 2017

Through the substitution of Li with Na in Li6C60, we synthesized a series of mixed alkali cluster... more Through the substitution of Li with Na in Li6C60, we synthesized a series of mixed alkali cluster intercalated fullerides, NaxLi6-xC60. These compounds share lattices of Na6C60 and Li6C60 with a cubic parameter linearly dependent on x. H2 absorption and desorption were studied by means of charge/discharge kinetic measurements and coupled calorimetric-manometric evaluation. By varying the stoichiometry, we found the best compromise among the absorption rate, temperature and amount of hydrogen for x = 0.5 and 1. Small concentrations of Na substituted to Li significantly lower the absorption temperature of Li6C60, improving the hydrogenation capacity, the kinetics, and the dehydrogenation enthalpy, the latter being 43.8 kJ mol(-1) H2 for x = 1. This study moves further toward the utilization of intercalated fullerides for hydrogen storage applications.

The Journal of Physical Chemistry C, 2017

J. Mater. Chem. A, 2015

Li6C60 can absorb up to 14 NH3 per C60; its structural evolution upon desorption is studied by ne... more Li6C60 can absorb up to 14 NH3 per C60; its structural evolution upon desorption is studied by neutron powder diffraction.

The Journal of Physical Chemistry C, 2015

Journal of Physics: Conference Series, 2014

The Journal of Physical Chemistry C, 2015

ABSTRACT For different hydrogenated metal intercalated fullerides (Na10C60-H, Li12C60-H, and Li28... more ABSTRACT For different hydrogenated metal intercalated fullerides (Na10C60-H, Li12C60-H, and Li28C60-H) the activation energies for hydrogen desorption were determined by DSC. The Vyazovkin advanced method (VA) was used for the calculation of the reaction model free activation energy as a function of the extent of conversion α. Activation energies are highest for low α and decrease for increasing α, between around 200−145 and 245−175 kJ/mol for the Na and Li compounds, respectively. The decrease of activation energy as a function of the extent of conversion can be explained by an increasing charge transfer to the C60H36+y cage during desorption. Na intercalation leads to a significant thermodynamic destabilization for hydrogen desorption. Dehydro- genation enthalpies of 52 (Na10C60-H), 66 (Li12C60-H), and 69 kJ/mol H2 (Li28C60-H) were determined. These values are lower compared to literature values for desorption of pure C60H36 (74 kJ/mol H2). The onsets of hydrogen desorption are 185 °C (Na10C60-H), 260 °C (Li12C60-H), and 250 °C (Li28C60-H) compared to >400 °C for pure C60H36

Journal of Applied Crystallography, 2015

ABSTRACT The crystal structure of N,N′-methylenebisacrylamide was determined through the geometry... more ABSTRACT The crystal structure of N,N′-methylenebisacrylamide was determined through the geometry optimization of the molecular unit with density functional theory and conformational analysis, and then through the calculation of the packing via a crystal structure prediction protocol, based on lattice energy minimization. All the calculated structures were ranked, comparing their powder pattern with the laboratory low-quality X-ray diffraction data. Rietveld refinement of the best three proposed structures allowed the most probable crystal arrangement of the molecules to be obtained. This approach was essential for disentangling the twinning problems affecting the single-crystal X-ray diffraction data, collected on samples obtained via recrystallization of powder, which definitely confirmed the predicted model. It was found that N,N′-methylenebisacrylamide shows a monoclinic structure in the space group C2/c, with lattice parameters a = 17.822 (12), b = 4.850 (3), c = 19.783 (14) Å, β = 102.370 (9)°, V = 1670 (2) Å3. Two strong interactions between the amide protons and the carbonyl groups of neighbouring molecules were found along the b axis, determining the crystal growth in the form of wires in this direction. This work provides a further example of how computational methods may help to investigate low-quality molecular crystals with standard diffraction techniques.

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Materials Research Bulletin

Abstract The addition of transition metals to alkali intercalated fullerides proved to enhance th... more Abstract The addition of transition metals to alkali intercalated fullerides proved to enhance their already good hydrogen absorption properties. Herein we present a study based on two different synthetic strategies, allowing the addition of nickel as aggregates with different size to the lithium fulleride Li6C60: the former is based on the metathesis of nickel chloride, while the latter on the thermal decomposition of nickel carbonyl clusters. The hydrogen-storage properties of the obtained materials have been investigated with manometric and calorimetric measurements, which indicated a clear enhancement of the final absorption value and kinetics with respect to pristine Li6C60, as a consequence of nickel surface catalytic activity towards hydrogen molecules dissociation. We found up to 10 % increase of the total H2 weight % absorbed (5.5 wt% H2) in presence of Ni aggregates. Furthermore, the control of the transition metal particles size distribution allowed reducing the hydrogen desorption enthalpy of the systems.

International Journal of Hydrogen Energy

Abstract Surface decoration of graphene-based nanostructures with metals has been predicted to be... more Abstract Surface decoration of graphene-based nanostructures with metals has been predicted to be an efficient way towards the development of resistant catalysts and novel materials for energy applications, such as hydrogen production and storage. We report on an extensive neutron scattering study of a defective graphene-based material decorated with nickel nanoparticles, obtained via the chemical decoration of thermally exfoliated graphite oxide. The combination of neutron diffraction and inelastic neutron scattering measurements has been used to characterize the low-dimensional carbon backbone and the presence of the nickel nanoparticles, organized at the nanometer scale on the graphene plane. The structural features of this system, along with the nickel capability of dissociating the hydrogen molecule upon hydrogen treatment, are herein discussed.

Physical chemistry chemical physics : PCCP, Jan 23, 2017

Through the substitution of Li with Na in Li6C60, we synthesized a series of mixed alkali cluster... more Through the substitution of Li with Na in Li6C60, we synthesized a series of mixed alkali cluster intercalated fullerides, NaxLi6-xC60. These compounds share lattices of Na6C60 and Li6C60 with a cubic parameter linearly dependent on x. H2 absorption and desorption were studied by means of charge/discharge kinetic measurements and coupled calorimetric-manometric evaluation. By varying the stoichiometry, we found the best compromise among the absorption rate, temperature and amount of hydrogen for x = 0.5 and 1. Small concentrations of Na substituted to Li significantly lower the absorption temperature of Li6C60, improving the hydrogenation capacity, the kinetics, and the dehydrogenation enthalpy, the latter being 43.8 kJ mol(-1) H2 for x = 1. This study moves further toward the utilization of intercalated fullerides for hydrogen storage applications.

The Journal of Physical Chemistry C, 2017

J. Mater. Chem. A, 2015

Li6C60 can absorb up to 14 NH3 per C60; its structural evolution upon desorption is studied by ne... more Li6C60 can absorb up to 14 NH3 per C60; its structural evolution upon desorption is studied by neutron powder diffraction.

The Journal of Physical Chemistry C, 2015

Journal of Physics: Conference Series, 2014

The Journal of Physical Chemistry C, 2015

ABSTRACT For different hydrogenated metal intercalated fullerides (Na10C60-H, Li12C60-H, and Li28... more ABSTRACT For different hydrogenated metal intercalated fullerides (Na10C60-H, Li12C60-H, and Li28C60-H) the activation energies for hydrogen desorption were determined by DSC. The Vyazovkin advanced method (VA) was used for the calculation of the reaction model free activation energy as a function of the extent of conversion α. Activation energies are highest for low α and decrease for increasing α, between around 200−145 and 245−175 kJ/mol for the Na and Li compounds, respectively. The decrease of activation energy as a function of the extent of conversion can be explained by an increasing charge transfer to the C60H36+y cage during desorption. Na intercalation leads to a significant thermodynamic destabilization for hydrogen desorption. Dehydro- genation enthalpies of 52 (Na10C60-H), 66 (Li12C60-H), and 69 kJ/mol H2 (Li28C60-H) were determined. These values are lower compared to literature values for desorption of pure C60H36 (74 kJ/mol H2). The onsets of hydrogen desorption are 185 °C (Na10C60-H), 260 °C (Li12C60-H), and 250 °C (Li28C60-H) compared to >400 °C for pure C60H36

Journal of Applied Crystallography, 2015

ABSTRACT The crystal structure of N,N′-methylenebisacrylamide was determined through the geometry... more ABSTRACT The crystal structure of N,N′-methylenebisacrylamide was determined through the geometry optimization of the molecular unit with density functional theory and conformational analysis, and then through the calculation of the packing via a crystal structure prediction protocol, based on lattice energy minimization. All the calculated structures were ranked, comparing their powder pattern with the laboratory low-quality X-ray diffraction data. Rietveld refinement of the best three proposed structures allowed the most probable crystal arrangement of the molecules to be obtained. This approach was essential for disentangling the twinning problems affecting the single-crystal X-ray diffraction data, collected on samples obtained via recrystallization of powder, which definitely confirmed the predicted model. It was found that N,N′-methylenebisacrylamide shows a monoclinic structure in the space group C2/c, with lattice parameters a = 17.822 (12), b = 4.850 (3), c = 19.783 (14) Å, β = 102.370 (9)°, V = 1670 (2) Å3. Two strong interactions between the amide protons and the carbonyl groups of neighbouring molecules were found along the b axis, determining the crystal growth in the form of wires in this direction. This work provides a further example of how computational methods may help to investigate low-quality molecular crystals with standard diffraction techniques.