Characterization of the surface chemistry of carbon materials by potentiometric titrations and temperature-programmed desorption

• Tipo: Artigo em Revista Científica Internacional
• Data: 2008

Autores

Gorgulho, HF (Autor) Outra; Mesquita, JP (Autor) Outra; Goncalves, F (Autor) Outra; Manuel Fernando R Pereira (Autor) FEUP; José Luis Figueiredo (Autor) FEUP

Revista

Título: Carbon

Vol. 46

Páginas: 1544-1555

ISSN: 0008-6223

Editora: Elsevier

Indexação

ISI Web of Knowledge - 124 Citações

ISI Web of Science

Scopus - 147 Citações

COMPENDEX

INSPEC

Classificação Científica

FOS: Ciências da engenharia e tecnologias > Outras ciências da engenharia e tecnologias

CORDIS: Ciências Tecnológicas

Outras Informações

ID Authenticus: P-003-VNQ

DOI: 10.1016/j.carbon.2008.06.045

Abstract (EN): TWO methods currently used to characterize oxygen-containing functional groups on the surface of carbon materials are compared, namely potentiometric titration (PT) and temperature-programmed desorption (TPD). Two materials were used, activated carbon and multi-walled carbon nanotubes, which were subsequently modified by oxidative treatments in order to produce samples with different amounts of surface groups. The concentrations of carboxylic acid groups determined by both techniques are in good agreement, but the quantitative result obtained by TPD is closer to the analytical concentration of the species obtained by elemental analysis. Discrepancies between the quantitative results are more pronounced at higher pK(a) values (weak acids), where the concentrations determined by PT are lower than those obtained by TPD. This directly reflects the effects of neglecting the electrostatic interaction parameter. The TPD method was particularly suited for the characterization of samples modified with ethylenediamine, which is anchored to specific oxygenated groups. PT results are useful to describe the material behaviour in aqueous solutions, where the activity of the surface groups depends not only on their concentrations, but also on their environment.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 12