▎ 摘　　要

NOVELTY - Synthesizing gas sensing materials based on graphene/stannic oxide composites, involves: adding stannic oxide particles with diameter of 20-100 nm into reaction tube in microwave plasma chemical vapor deposition (MPCVD) device; controlling the chamber at pressure of 100-300 mbar; carrying carbon sources with flow rate of 10-100 sccm by working gas with flow rate of 100-500 sccm, which is passing to hydrogen and/or argon, into the area where the microwave plasma reaction occurs, the carbon sources are passing to kind of organic compounds having carbon atoms of SP3 or SP2 e.g. methane, methanol, ethanol and methyl formate; turning on the power supply of the MPCVD device and starting the reaction to deposit graphene on stannic oxide particles with growth time of 5-40 minutes; then, forming the graphene/ stannic oxide composites with high specific surface area; and characterizing the gas sensing properties of the composites. USE - The method is useful for synthesizing gas sensing materials based on graphene/stannic oxide composites. ADVANTAGE - The method provides the composites with a high specific surface area; greatly increases the surface carrier concentration of graphene and provides a simple method to synthesize carbon-coated stannic oxide composite materials for gas sensing applications. DETAILED DESCRIPTION - Synthesizing gas sensing materials based on graphene/stannic oxide composites, comprises: adding stannic oxide particles with a diameter of 20-100 nm into the reaction tube in the microwave plasma chemical vapor deposition (MPCVD) device; controlling the vacuum chamber at a pressure of 100-300 mbar; carrying the carbon sources with a flow rate of 10-100 sccm by the working gas with a flow rate of 100-500 sccm, which is passing to hydrogen and/or argon, into the area where the microwave plasma reaction occurs, the carbon sources are passing to be at least one kind of organic compounds containing carbon atoms of SP3 or SP2 e.g. methane, methanol, ethanol and methyl formate; turning on the power supply of the MPCVD device and starting the reaction to deposit graphene on stannic oxide particles with a growth time of 5-40 minutes; after the reaction, forming the graphene/ stannic oxide composites with a high specific surface area; and then characterizing the gas sensing properties of the synthesized graphene/stannic oxide composites. DESCRIPTION OF DRAWING(S) - The figure shows a schematic diagram of the MPCVD system.