▎ 摘　　要

A series of graphene-ZnGa2O4 composites (G-ZnGa2O4) were synthesized by a hydrothermal method. The prepared samples were characterized by XRD, SEM, TEM, Raman and XPS. The gas sensing properties of the G-ZnGa2O4 composites were investigated. The results indicate that the graphene content has a great influence on the response and the gas sensing selectivity; the optimal composition of G-ZnGa2O4 gas sensing composites is 0.1 wt% G-ZnGa2O4. The sensor based on 0.1 wt% G-ZnGa2O4 exhibits high response to 1000 mu L/L formaldehyde when operated at 203 degrees C and the response reaches 32.2; the detection limit for formaldehyde is as low as 1 mu L/L; the gas sensing selectivity to formaldehyde is also good and the ratio Of S-1000 (mu L/L) (formaldehyde) and S-1000 (mu L/L) (acetone) reaches 26.8. The response time and recovery time for 1000 mu L/L formaldehyde are 11 and 5 s and the response time and recovery time for 1 mu L/L formaldehyde are 6 and 5 s, respectively.