Preparation and gas-sensing performance of GO/SnO2/NiO gas-sensitive composite materials

In this study, a SnO2/NiO composite material was prepared via a co-precipitation method. After calcination at 400 °C for 2 h, a binary composite material (SnO2/NiO) with good crystallization was obtained. Then, a graphene oxide (GO)/SnO2/NiO ternary composite material was prepared using a hydrothermal method, in which SnO2/NiO performed secondary growth on the GO surface. The XRD results showed that SnO2/NiO exhibited good crystallinity and proved the existence of a chemical bond, Sn–O–C, which was due to the formation of a chemical bond between GO and SnO2/NiO. Lastly, GO/SnO2/NiO was successfully prepared and coated on the surface of a gold electrode for gas sensitivity test. A good response to acetone gas in the concentration range of 10–500 ppm at 350 °C was determined. Compared with SnO2/NiO, GO/SnO2/NiO showed remarkable improvements in response time, recovery time, and sensitivity. At 350 °C, the sensitivity of acetone with a concentration of 50 ppm was 21.11, the response time was only 5 s, and the recovery time was 150 s. GO/SnO2/NiO comprised two structures, chemical bond and p-n junction, which exerted a synergistic effect. GO/SnO2/NiO indicated an excellent application prospect in acetone gas detection.