Quantitative determination of acidic groups in functionalized graphene by direct titration

0459061 - ÚACH 2017 RIV NL eng J - Journal Article
Ederer, J. - Janoš, P. - Ecorchard, Petra - Štengl, Václav - Bělčická, Zuzana - Šťastný, Martin - Pop-Georgievski, Ognen - Dohnal, V.
Quantitative determination of acidic groups in functionalized graphene by direct titration.
Reactive and Functional Polymers. Roč. 103, JUN (2016), s. 44-53. ISSN 1381-5148. E-ISSN 1873-166X
R&D Projects: GA ČR(CZ) GA14-05146S
Institutional support: RVO:61388980 ; RVO:61389013
Keywords : Acid-base titration * Carboxylic functional groups * Graphene oxide * Phenolic functional groups * Proton-binding model
Subject RIV: CA - Inorganic Chemistry; CD - Macromolecular Chemistry (UMCH-V)
Impact factor: 3.151, year: 2016

Direct titration with NaOH was used to quantify the acidic functional group content in graphene oxide (GO). Three different methods were used to evaluate the experimental data: the first derivation of the titration curve, Gran linearization and an empirical approach suggested by Ritchie and Perdue for the evaluation of the titration data for humic substances. Two types of acidic functional groups were identified and classified, more or less arbitrarily, as being either carboxylic or phenolic. Typically, the carboxylic acid group contents ranged from ca. 0.80 to 1.70 mmol/g, except for the carboxylated GO prepared by the reaction with chloroacetic acid, which contained significantly more carboxylic acid groups. The titration results are consistent with those obtained by instrumental methods such as X-ray diffraction (XRD), infrared spectroscopy (IR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). For modelling purposes (proton binding and metal binding), a bimodal continuous distribution model was proposed, and its parameters were estimated from the titration data.
Permanent Link: http://hdl.handle.net/11104/0259317