Yongchun Tong

A theoretical study of the binding mechanisms of atomic platinum on Be-, B-, N-, O-doped (6, 6) single-walled carbon nanotubes

In the present work, density functional theory (DFT) is used to investigate the binding mechanism of atomic platinum on several heteroatom (Be, B, N, and O) doped (6, 6) single-walled carbon nanotubes. The binding abilities in ascending order by dopants are found to be pristine, nitrogen, boron, beryllium, and oxygen. The adsorption mechanisms of Pt on these nanotubes have been discussed based on the adsorption geometries, frontier orbitals, and projected density of states. Due to the unused binding site of the carbon atom created by O-doping, the O-doped CNT presents the strongest binding for atomic Pt. It is found that the degree of s-orbital of the carbon atom involved in the C–Pt bond could reflect the binding strength of Pt on these doped CNT supports.

THEORETICAL STUDY ON THE H2 ACTIVATION BY PtO+ AND

Gas-phase H2 activation by PtO+ and

{\rm PtO}_{2}^{+}

{\rm PtO}_{2}^{+}

IN THE GAS PHASE

were studied at the density functional level of theory (DFT) using the relativistic effective core potential (RECP) of Stuttgart basis sets on platinum atom and UB3LYP/6-311+G(2d,2p) level on hydrogen and oxygen atoms. Two reaction profiles corresponding to the doublet and quartet multiplicities were investigated in order to ascertain the presence of some spin inversion during the H2 reduction. The electron-transfer reactivity of the reactions were analyzed using the two-state model, and the strongly crossing behavior on the transition state (TS) area were shown. Finally, the actions of frontier molecular orbitals in minimum-energy crossing point (MECP) have been illuminated briefly. These theoretical results can act as a guide to further theoretical and experimental research. H2 activation mediated by metal oxide cations were found to be an exothermic spin-forbidden process resulting from a crossing between quartet and doublet profiles. To evaluate ...

Attachment of CO to a (6, 6) CNT with a Sc adsorbate atom

We have comparatively investigated the adsorption behaviors of Sc atom on the external and internal surfaces of the pristine, Stone-Wales (SW), and single-vacancy (SV) defect nanotubes based on the density functional theory. Our results reveal that the stability of Sc atom onto the external and internal surfaces of the carbon nanotubes is in following orders by defect: SV>SW1>SW2>pristine (external surfaces), SV>SW2>SW1>pristine (internal surfaces). To explore the reactivity of Sc@CNT/SW/SV complexes which can serve as a gas sensor or a catalyst in direct methanol fuel cell (DMFC), the interaction between a CO molecule and Sc@CNT/SW/SV is also examined. The SV defect in carbon nanotubes can make the confined Sc atom with good CO adsorption property, while the confined Sc in the SW defect carbon nanotube has good anti-CO poisoning. By our studies, it plays an important guidance role in improving the activity of metal catalyst and the sensitivity and stability of metal particles to functional molecules, and provides the theoretical basis for designing new carbon nanotube-based metal catalyst.