Non-linear thermogravimetric mass spectrometry of carbon materials providing direct speciation separation of oxygen functional groups

Thermogravimetric mass spectrometry (TG-MS) is an established way to analyze oxygen containing surface functional groups of carbon materials. Thermal stabilities and structures of functional groups influence their decomposition temperatures and products (CO, CO2). In this work, a non-linear procedure with isothermal steps is presented enabling a separation of functional groups by different decomposition temperatures. Nitrosulfuric acid functionalized carbon materials like multi-walled carbon nanotubes (MWCNT) and graphite were used to design the temperature program. Comparative studies of linear and non-linear heating experiments in argon and hydrogen containing atmosphere were performed to state the benefits and limits of both methods. The distinct advantage of non-linear thermal analysis is demonstrated by an application-oriented experiment where only selected functional groups are consumed. (c) 2018 The Author(s). Published by Elsevier Ltd.