A comprehensive study of various amine-functionalized graphene oxides for room temperature formaldehyde gas detection: Experimental and theoretical approaches

Graphene oxide (GO) was functionalized with a series of amine precursors including ammonia, methylamine, ethylamine, ethylenediamine, dimethylamine, aniline, and 1,4-phenylenediamine (PDA) by a facile solvothermal method for room temperature formaldehyde (HCHO) gas sensing. The as-prepared materials were fabricated via a simple drop-casting method and screened based on the response to 300 ppm HCHO gas at room temperature. GO functionalized with 1,4-phenylenediamine (PDA-GO) was the most sensitive toward 300 ppm HCHO compared to combinations of GO with other amines. The PDA-GO was characterized by transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectrometer, and X-ray photoelectron spectroscopy to investigate the morphology and chemical structure. Remarkably, the response of PDA-GO was almost 24 times higher than that of GO and reached up to 24%. The excellent HCHO sensing properties of the PDA-GO sensor were elucidated by DFT study, which are attributed to the harmony of strong bond formation energy, adsorption energy, and charge transfer during the PDA-GO physically interacting with HCHO. Compared with other reported graphene-based room temperature HCHO gas sensors, PDA-GO exhibits great potential and represents a contribution to the limited studies in the field of organic molecule-functionalized graphene derivatives for HCHO sensor applications.