A Novel Flow Chemistry Approach to Covalent Functionalization of 3D Graphene Aerogels

Tuning the surface chemistry of 3D graphene structures, such as hydrogels and aerogels, is critical for advancing their chemical and physical properties, which are essential for material design. Here, we present an innovative in-flow covalent functionalization approach based on diazonium salt chemistry to introduce new functionalities into the 3D graphene aerogel backbone while preserving its porous architecture. To achieve this, we designed a flow-based reactor tailored for the functionalization of macroscopic aerogel samples, addressing limitations of noncovalent methods including molecular slippage. Notably, the proposed method operates at room temperature, a significant advantage over existing techniques that often require high thermal conditions. Additionally, to overcome challenges associated with solid-state Raman analysis of graphene-based compounds, we proposed a statistical model to enhance the reproducibility of the process and rationalize I _D/I _G ratios post-treatment. This work demonstrates the feasibility of in-flow covalent functionalization of 3D graphene aerogels, opening new perspectives for the development of customizable porous carbon-based materials for various technological applications.