Three-Dimensional Graphene-Based Foams with Greater Electron Transferring Areas Deriving High Gas Sensitivity

Graphene foams are promising three-dimensional (3D) architectures with the combination of the intrinsic nature of graphene and unique cellular structures for various realms. Herein, a facile technique is developed by combining supramolecular assembly with lyophilization to functionalize graphene with donor-pi-acceptor (D-pi-A) molecules and then massively transform the two-dimensional (2D) plane nanosheets into 3D foams. The as-prepared gas sensors work at room temperature (RT) and reveal comprehensive gas sensing performance with an ultrahigh response (R-a/R-g = 3.2, 10 ppm), excellent selectivity, and reliable repeatability toward NO2. Notably, a gas sensing enhancement mechanism with density functional theory (DFT) calculations is proposed to unravel the synergetic effect of the Greater Electron Transferring Area and the specific 3D foam structure for the enhancement of charge transfer and NO2 adsorption. The combination of supramolecular assembly and the lyophilization technique provides a strategy to prepare 3D architectural graphene-based materials for high-performance gas sensors and chemical trace detectors.

Automated summary

The study presents a facile technique combining supramolecular assembly and lyophilization to functionalize graphene and transform 2D nanosheets into 3D foams for gas sensing applications. The gas sensors exhibit ultrahigh response, excellent selectivity, and reliable repeatability towards NO2, showing promising potential for high-performance gas sensors and chemical trace detectors.