▎ 摘　　要

NOVELTY - Cobalt sulfide/reduced graphene oxide composite comprises cobalt sulfide nanoflower and graphene covered on the cobalt sulfide nanoflowers. USE - Cobalt sulfide/reduced graphene oxide composite used in preparation gas sensor or the detection gas (claimed) and in industrial production, medical diagnosis and environment protection. ADVANTAGE - The cobalt sulfide/reduced graphene oxide composite prevents the stack and agglomeration of the graphene sheet, increases the material and gas of the contact, improves the electron transfer to enhance the gas-sensitive performance, and exhibits good research prospect. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: 1. method for preparing cobalt sulfide/reduced graphene oxide composite, involving: mixing cobalt sulfide nanoflower with the oxidized graphene and then heat treating to obtain product; 2. gas sensor, comprises a conductive base, interdigital electrode and gas sensitive material of interdigital electrode surface, where the gas sensitive material is the cobalt sulfide/reduction oxidation graphene composite; and 3. method for detecting nitrogen oxide in environment, involving: placing the gas sensor into the environment to be detected, and detecting the nitrogen oxide in the environment.