Graphene oxide nanosheets modified with TiO2 nanoparticles for highly sensitive NH3 detection at room temperature

Abstract

In this work, graphene oxide (GO) nanosheets modified with TiO2 nanoparticles were prepared by a simple solution ultrasonication method. The GO/TiO2 nanocomposites were successfully synthesized by in-situ oxidation of Ti3C2Tx nanosheets on the surface of GO nanosheets. It is revealed that spindle-shaped TiO2 nanoparticles are uniformly distributed on the GO nanosheets, which will provide more active sites for NH3 adsorption. The response of NH3 sensor based on GO/TiO2 nanocomposites to 100 ppm NH3 at room temperature is approximately twice that of pure GO, which may be attributed to its unique structure and GO/TiO2 heterojunction. The GO/TiO2 sensors also demonstrated good stability, ideal repeatability, great selectivity, and a quick response/recovery time of 13/33 s. Lastly, density-functional theory (DFT) was used to examine the adsorption behavior and charge transfer capacity between NH3 molecules and the materials. The results indicate that the GO/TiO2 nanocomposites are potentially useful materials for highly sensitive NH3 detection at room temperature.