▎ 摘　　要

NOVELTY - A formaldehyde gas sensor gas-sensitive material comprises tin(III) oxide and reduced graphene oxide, where the tin(III) oxide nanosheets are stacked together to form three-dimensional flower-like structure, and the reduced graphene oxide is formed on a tin(III) oxide nanosheet to form tin(III) oxide-reduced graphene oxide heterojunction gas-sensitive material, and the heterojunction is p-n junction. USE - Formaldehyde gas sensor gas-sensitive material for use in field of environmental gas monitoring and industrial gas analysis (claimed). ADVANTAGE - The formaldehyde gas sensor gas-sensitive material has high sensitivity and selectivity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following: (1) a method for preparing formaldehyde gas sensor gas-sensitive material, which involves dissolving stannous chloride and citrate in water until fully dissolved, and adding a graphene oxide dispersion and stirring to obtain a uniform mixed solution, adding a sodium hydroxide solution to the mixed solution to obtain a precursor solution, subjecting the precursor solution to a hydrothermal reaction, and centrifuging the product to obtain the finished product (2) a formaldehyde gas sensor, comprises a base, a support leg, a binding post, a ceramic tube, a heating wire, a ring-shaped metal electrode, a gas sensing material and a wire (3) a method for producing formaldehyde gas sensor.