Abstract (EN):
A comprehensive experimental and theoretical study of the surface chemistry of multi-walled carbon nanotubes (CNTs) and its effect on the deposition of ruthenium nanoparticles is reported. It is shown that the oxidation of CNTs by nitric acid creates various oxygen surface functional groups (SFGs) on the CNT external surface which is a critical step for the metal grafting. In particular, it is demonstrated that carboxylic acid, carboxylic anhydride and lactone groups act as anchoring centers for the Ru precursor, presumably as surface acetato ligands. The stability of Ru nanoparticles, modeled by a Rul3 cluster, on different adsorption sites follows the order: Gr-DV-(COOH)2 > Gr-DV > Gr (where DV is a double vacancy and Gr the graphene surface). It is shown that, after a high-temperature treatment performed to remove the SFGs, the Ru/CNT material can react with oxygen from air via a surface reconstruction reaction, which reforms a stable Ru-acetato interface.
Language:
English
Type (Professor's evaluation):
Scientific