Quantum Chemical Simulation of Phenol-Formaldehyde Resin Carbonization in the Presence of Phosphoric Acid: Computational Evidence of Michaelis–Arbuzov-Type Reaction

Quantum-chemical semiempirical simulation of phenol-formaldehyde resin carbonization was performed by PM6 method, resulting in atomic level models of neat and P-doped disordered carbon structures. Mechanisms of curved-plane carbon fragments formation from postpolymeric chains is discussed, supported by change in statistic characteristics of the clusters. Transformation of phosphoric esters to phosphonates by Michaelis–Arbuzov-type reaction is described

Quantum Chemical Simulation of Phenol-Formaldehyde Resin Carbonization in the Presence of Phosphoric Acid: Computational Evidence of Michaelis–Arbuzov-Type Reaction

Quantum-chemical semiempirical simulation of phenol-formaldehyde resin carbonization was performed by PM6 method, resulting in atomic level models of neat and P-doped disordered carbon structures. Mechanisms of curved-plane carbon fragments formation from postpolymeric chains is discussed, supported by change in statistic characteristics of the clusters. Transformation of phosphoric esters to phosphonates by Michaelis–Arbuzov-type reaction is described

Quantum Chemical Simulation of Phenol-Formaldehyde Resin Carbonization in the Presence of Phosphoric Acid: Computational Evidence of Michaelis–Arbuzov-Type Reaction

Quantum-chemical semiempirical simulation of phenol-formaldehyde resin carbonization was performed by PM6 method, resulting in atomic level models of neat and P-doped disordered carbon structures. Mechanisms of curved-plane carbon fragments formation from postpolymeric chains is discussed, supported by change in statistic characteristics of the clusters. Transformation of phosphoric esters to phosphonates by Michaelis–Arbuzov-type reaction is described

Density Functional Theory versus Complete Active Space Self-Consistent Field Investigation of the Half-Metallic Character of Graphite-Like and Amorphous Carbon Nanoparticles

Model carbon nanoparticles representative of the graphite-like and amorphous domains of active carbon are investigated with density functional theory (DFT) and complete active space self-consistent field (CASSCF) methods. Cyclic carbon clusters containing conjugated carbene groups are found to undergo Jahn–Teller distortion. More importantly, the half-metallicity, that is, the equal or similar stability of various spin states, previously suggested by DFT calculations for both types of nanosized clusters is confirmed by CASSCF calculations. Furthermore, the model carbon clusters are found to possess a multiconfigurational electronic structure dominated by high-spin configurations. When compared to CASSCF results, the single-reference DFT predicts proper electronic structures, characterized by antiferromagnetically coupled electron pairs, at the expense of spin contamination as a reflection of the multiconfigurational character. In fact, spin contamination, which is normally viewed as an error, does not corrupt the energetics of the half-metallic systems and therefore does not preclude the applicability of DFT to such systems

Spin Filter Circuit Design Based on a Finite Single-Walled Carbon Nanotube of the Zigzag Type

A complete circuit, consisting of a zigzag-edge single-walled carbon nanotube (zSWCNT) as a gate with attached transacetylene chains anchoring 2-mercaptopyridine residues as conducting junctions and gold clusters as electrodes, is investigated by density functional theory, with both plane-wave and atom-centered Gaussian bases. Spin polarization is found to be preserved in zSWCNTs upon covalent grafting of the conducting substituents, and spin conductivity is observed through the entire circuit. These findings are relatively insensitive to the zSWCNT diameter and the gold cluster size. This suggests that the present design may be an interesting candidate for a nanotube-based spin filter prototype

Spin Filter Circuit Design Based on a Finite Single-Walled Carbon Nanotube of the Zigzag Type

A complete circuit, consisting of a zigzag-edge single-walled carbon nanotube (zSWCNT) as a gate with attached transacetylene chains anchoring 2-mercaptopyridine residues as conducting junctions and gold clusters as electrodes, is investigated by density functional theory, with both plane-wave and atom-centered Gaussian bases. Spin polarization is found to be preserved in zSWCNTs upon covalent grafting of the conducting substituents, and spin conductivity is observed through the entire circuit. These findings are relatively insensitive to the zSWCNT diameter and the gold cluster size. This suggests that the present design may be an interesting candidate for a nanotube-based spin filter prototype

Calorimetric Study of Propane and Propylene Adsorption on the Active Surface of Multiwalled Carbon Nanotube Catalysts

Hunting for the active site: Multiwalled carbon nanotubes are investigated as an adsorbent for propane and propylene in the view of catalytic application in the oxidative dehydrogenation of propane. Support by XPS and TPD analyses gives an indication of a quantitative description of the carbon surface under reaction conditions