▎ 摘　　要

NOVELTY - A composite nano-film material comprises a zinc oxide nanosheet as a main component, and covered with graphene quantum dot and tin dioxide quantum crystal grain, which is film shaped. The zinc oxide nanosheet is hexagonal, and having average side length of 1.5-2.4 mu m, and average thickness of 50-100 nm. The graphene quantum dot has average size of 3.2-4.3 nm. The tin dioxide quantum crystal grains has average size of 3.5-5.2 nm. USE - Composite nano-film material used for gas-sensitive sensor element for detecting hydrogen sulfide gas (all claimed). ADVANTAGE - The composite nano-film material is prepared by simple and economical method. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a gas-sensitive sensor element.