Pierre Kuhn - Academia.edu (original) (raw)
Papers by Pierre Kuhn
Energy & Environmental Science, 2009
Philippe Makowski was born in Cologne (Germany) in 1981. He received his Master of Science in sup... more Philippe Makowski was born in Cologne (Germany) in 1981. He received his Master of Science in supramolecular and colloidal chemistry in 2006 from the Université de Versailles St Quentin in Versailles (France). He is currently pursuing a PhD degree at the Max Planck Institute ...
Journal of The American Chemical Society, 2008
High surface area organic materials featuring both micro- and mesopores were synthesized under io... more High surface area organic materials featuring both micro- and mesopores were synthesized under ionothermal conditions via the formation of polyaryltriazine networks. While the polytrimerization of nitriles in zinc chloride at 400 degrees C produces microporous polymers, higher reaction temperatures induce the formation of additional spherical mesopores with a narrow dispersity. The nitrogen-rich carbonaceous polymer materials thus obtained present surface areas and porosities up to 3300 m(2) g(-1) and 2.4 cm(3) g(-1), respectively. The key point of this synthesis relies on the occurrence of several high temperature polymerization reactions, where irreversible carbonization reactions coupled with the reversible trimerization of nitriles allow the reorganization of the dynamic triazine network. The ZnCl2 molten salt fulfills the requirement of a high temperature solvent, but is also required as catalyst. Thus, this dynamic polymerization system provides not only highly micro- and mesoporous materials, but also allows controlling the pore structure in amorphous organic materials.
Macromolecules, 2009
... Pierre Kuhn*, Arne Thomas and Markus Antonietti. Max Planck Institute of Colloids and Interfa... more ... Pierre Kuhn*, Arne Thomas and Markus Antonietti. Max Planck Institute of Colloids and Interfaces, Department of Colloid Chemistry, Research Campus Golm, 14424 Potsdam, Germany. Macromolecules , 2009, 42 (1), pp 319–326. ...
Chemical Communications, 2008
Carbonaceous polymer networks with tunable porosity were found to behave as exceptional adsorbent... more Carbonaceous polymer networks with tunable porosity were found to behave as exceptional adsorbents toward large organic molecules such as organic dyes.
Macromolecular Rapid Communications, 2009
A new generation of porous polymers was made for various energy-related applications, e.g., as fu... more A new generation of porous polymers was made for various energy-related applications, e.g., as fuel cell membranes, as electrode materials for batteries, for gas storage, partly from renewable resources. This review intends to catch this emerging field by reporting on a variety of different approaches to make high performing polymers porous. This includes template techniques, polymers with inherent microporosity, polymer frameworks by ionothermal polymerization, and the polymerization of carbon from appropriate precursors and by hydrothermal polymerization. In this process, we try to not only identify the current status of the field, but also point to open question and tasks to identify the potentially relevant progress.
Angewandte Chemie-international Edition, 2008
Chemie Ingenieur Technik, 2009
Angewandte Chemie-international Edition, 2009
The development of catalyst systems for the direct lowtemperature oxidation of methane to methano... more The development of catalyst systems for the direct lowtemperature oxidation of methane to methanol has been one of the major challenges in catalysis over the last decades. The high binding energy of the CH 3 ÀH bond (435 kJ mol À1 ) together with the ease of overoxidation to form CO 2 require not only a highly active but also a highly selective catalyst system to tackle this reaction. In the past, various investigations addressed this challenge. However, the catalysts mostly suffered from irreversible reduction and bulk metal formation, together with consequently poor selectivity. Some palladium, gold, and mercury complexes with superior stability initially appeared to be promising but still suffer from turnover frequencies (TOFs) below 1 h À1 . In the field of heterogeneous catalysis, nearly all reported investigations involve temperatures far above 250 8C over basic oxides, transition-metal oxides, and iron complexes encapsulated in zeolites. All these catalysts showed poor selectivity owing to overoxidation, and maximum methanol yields were around 5 %. Promising progress in molecular catalysis, however, has recently been made by Periana et al., who demonstrated the selective low-temperature oxidation of methane at temperatures around 200 8C over platinum bipyrimidine complexes in concentrated sulfuric acid. Methane conversions above 90 % at 81 % selectivity to methylbisulfate were reached. However, despite these promising results, commercial application seems to be hampered by difficult separation and recycling of the molecular catalyst.
Chemsuschem, 2010
The direct low-temperature oxidation of methane to methanol is demonstrated on a highly active ho... more The direct low-temperature oxidation of methane to methanol is demonstrated on a highly active homogeneous molecular catalyst system and on heterogeneous molecular catalysts based on polymeric materials possessing ligand motifs within the material structure. The N-(2-methylpropyl)-4,5-diazacarbazolyl-dichloro-platinum(II) complex reaches significantly higher activity compared to the well-known Periana system and allows first conclusions on electronic and structural requirements for high catalytic activity in this reaction. Interestingly, comparable activities could be achieved utilizing a platinum modified poly(benzimidazole) material, which demonstrates for the first time a solid catalyst with superior activity compared to the Periana system. Although the material shows platinum leaching, improved activity and altered electronic properties, compared to the conventional Periana system, support the proposed conclusions on structure–activity relationships. In comparison, platinum modified triazine-based catalysts show lower catalytic activity, but rather stable platinum coordination even after several catalytic cycles. Based on these systems, further development of improved solid catalysts for the direct low-temperature oxidation of methane to methanol is feasible.
Energy & Environmental Science, 2009
Philippe Makowski was born in Cologne (Germany) in 1981. He received his Master of Science in sup... more Philippe Makowski was born in Cologne (Germany) in 1981. He received his Master of Science in supramolecular and colloidal chemistry in 2006 from the Université de Versailles St Quentin in Versailles (France). He is currently pursuing a PhD degree at the Max Planck Institute ...
Journal of The American Chemical Society, 2008
High surface area organic materials featuring both micro- and mesopores were synthesized under io... more High surface area organic materials featuring both micro- and mesopores were synthesized under ionothermal conditions via the formation of polyaryltriazine networks. While the polytrimerization of nitriles in zinc chloride at 400 degrees C produces microporous polymers, higher reaction temperatures induce the formation of additional spherical mesopores with a narrow dispersity. The nitrogen-rich carbonaceous polymer materials thus obtained present surface areas and porosities up to 3300 m(2) g(-1) and 2.4 cm(3) g(-1), respectively. The key point of this synthesis relies on the occurrence of several high temperature polymerization reactions, where irreversible carbonization reactions coupled with the reversible trimerization of nitriles allow the reorganization of the dynamic triazine network. The ZnCl2 molten salt fulfills the requirement of a high temperature solvent, but is also required as catalyst. Thus, this dynamic polymerization system provides not only highly micro- and mesoporous materials, but also allows controlling the pore structure in amorphous organic materials.
Macromolecules, 2009
... Pierre Kuhn*, Arne Thomas and Markus Antonietti. Max Planck Institute of Colloids and Interfa... more ... Pierre Kuhn*, Arne Thomas and Markus Antonietti. Max Planck Institute of Colloids and Interfaces, Department of Colloid Chemistry, Research Campus Golm, 14424 Potsdam, Germany. Macromolecules , 2009, 42 (1), pp 319–326. ...
Chemical Communications, 2008
Carbonaceous polymer networks with tunable porosity were found to behave as exceptional adsorbent... more Carbonaceous polymer networks with tunable porosity were found to behave as exceptional adsorbents toward large organic molecules such as organic dyes.
Macromolecular Rapid Communications, 2009
A new generation of porous polymers was made for various energy-related applications, e.g., as fu... more A new generation of porous polymers was made for various energy-related applications, e.g., as fuel cell membranes, as electrode materials for batteries, for gas storage, partly from renewable resources. This review intends to catch this emerging field by reporting on a variety of different approaches to make high performing polymers porous. This includes template techniques, polymers with inherent microporosity, polymer frameworks by ionothermal polymerization, and the polymerization of carbon from appropriate precursors and by hydrothermal polymerization. In this process, we try to not only identify the current status of the field, but also point to open question and tasks to identify the potentially relevant progress.
Angewandte Chemie-international Edition, 2008
Chemie Ingenieur Technik, 2009
Angewandte Chemie-international Edition, 2009
The development of catalyst systems for the direct lowtemperature oxidation of methane to methano... more The development of catalyst systems for the direct lowtemperature oxidation of methane to methanol has been one of the major challenges in catalysis over the last decades. The high binding energy of the CH 3 ÀH bond (435 kJ mol À1 ) together with the ease of overoxidation to form CO 2 require not only a highly active but also a highly selective catalyst system to tackle this reaction. In the past, various investigations addressed this challenge. However, the catalysts mostly suffered from irreversible reduction and bulk metal formation, together with consequently poor selectivity. Some palladium, gold, and mercury complexes with superior stability initially appeared to be promising but still suffer from turnover frequencies (TOFs) below 1 h À1 . In the field of heterogeneous catalysis, nearly all reported investigations involve temperatures far above 250 8C over basic oxides, transition-metal oxides, and iron complexes encapsulated in zeolites. All these catalysts showed poor selectivity owing to overoxidation, and maximum methanol yields were around 5 %. Promising progress in molecular catalysis, however, has recently been made by Periana et al., who demonstrated the selective low-temperature oxidation of methane at temperatures around 200 8C over platinum bipyrimidine complexes in concentrated sulfuric acid. Methane conversions above 90 % at 81 % selectivity to methylbisulfate were reached. However, despite these promising results, commercial application seems to be hampered by difficult separation and recycling of the molecular catalyst.
Chemsuschem, 2010
The direct low-temperature oxidation of methane to methanol is demonstrated on a highly active ho... more The direct low-temperature oxidation of methane to methanol is demonstrated on a highly active homogeneous molecular catalyst system and on heterogeneous molecular catalysts based on polymeric materials possessing ligand motifs within the material structure. The N-(2-methylpropyl)-4,5-diazacarbazolyl-dichloro-platinum(II) complex reaches significantly higher activity compared to the well-known Periana system and allows first conclusions on electronic and structural requirements for high catalytic activity in this reaction. Interestingly, comparable activities could be achieved utilizing a platinum modified poly(benzimidazole) material, which demonstrates for the first time a solid catalyst with superior activity compared to the Periana system. Although the material shows platinum leaching, improved activity and altered electronic properties, compared to the conventional Periana system, support the proposed conclusions on structure–activity relationships. In comparison, platinum modified triazine-based catalysts show lower catalytic activity, but rather stable platinum coordination even after several catalytic cycles. Based on these systems, further development of improved solid catalysts for the direct low-temperature oxidation of methane to methanol is feasible.