Wangbing Zhang

Preparation and gas-sensing properties of SnO2/graphene quantum dots composites via solvothermal method

SnO2/graphene quantum dots (GQDs) nano-composites were prepared via solvothermal method (160xa0°C, 10xa0h), in which graphene quantum dots were synthesized from graphene oxide by one-step solvothermal method. The nano-composites were characterized by means of HRTEM, XRD, SEM, FTIR, XPS and N2 adsorption–desorption, respectively. The sensor devices were fabricated using SnO2/GQDs nano-composites as sensing materials. The effect of the GQDs content on the gas-sensing responses and the gas-sensing selectivity was investigated. The experimental results showed that the sensor based on SnO2/GQDs nano-composite (S-2) exhibited good response and good selectivity to acetone vapor. When operating at 275xa0°C, the responses of the sensor based on SnO2/GQDs nano-composite (S-2) to 1000 and 0.1xa0ppm acetone reached 120.6 and 1.3, respectively; the response time and the recovery time for 1000xa0ppm acetone were 17 and 13xa0s, respectively.

The acetic acid gas sensing properties of graphene quantum dots (GQDs)–ZnO nanocomposites prepared by hydrothermal method

Graphene quantum dots (GQDs) and GQDs–ZnO composites with different amounts of GQDs have been synthesized via a hydrothermal method. The GQDs were characterized HRTEM and size distribution analyzer. The GQDs–ZnO composites were studied by XRD, SEM, TG, FTIR, Raman and XPS, respectively. The gas sensing properties of GQDs–ZnO composites were investigated. It was found that the amount of GQDs in the composite has great influence on the gas response and gas sensing selectivity of the composite; the sensors based on GQDs–ZnO composites could be operated at room temperature and showed higher response to acetic acid gas than pure ZnO sensor; the sensor based on GQDs–ZnO (S-10) composite could detect 1xa0ppm acetic acid vapor at room temperature.