Kinetic investigation of the multi-step thermal decomposition of graphene oxide paper

Thermal annealing is a convenient, low-cost, and versatile route to fine-tune the physicochemical properties of graphene oxide paper (GOP) toward various applications. Therefore, a thorough monitoring of the thermal decomposition of GOP is generally required for a precise and safe adjustment of its properties. From this perspective, thermogravimetry analysis (TG-A) is employed to scrutinize the multi-step thermal decomposition process of GOP under a nitrogen atmosphere. GOP is elaborated from modified hummers graphene oxide (GO). Nonisothermal TG-A is carried out for the as-prepared GOP at different heating rates. Activation energy is assessed for the overall decomposition process by several isoconversional models. Derivative thermogravimetry (D-TG) curves are derived numerically from TG-A data. To find the number of reactions involved, D-TG curves are deconvoluted into individual peaks by the well-known Fraser–Suzuki function. The obtained results show that the thermal decomposition of GOP consists mainly of six reactions: physisorbed water dehydration, rearrangement and elimination of oxygen functional groups, disproportionation reaction, chemisorbed water dehydration, desulfonation, and degradation of the carbon framework. Furthermore, kinetic triplets for each of the individual reactions are figured out by coupling the Vyazovkin nonlinear method with the compensation effect.