Carboxyl graphene oxide/graphene composite structure for the chemiresistive detection of acetaldehyde at room temperature

The work systematically investigates the sensing performance of the carboxyl graphene oxide/graphene sensor (GO-COOH/Graphene) for acetaldehyde (CH3CHO). Firstly, carboxylated graphene oxide was prepared by employing sodium hydroxide and chloroacetic acid to convert epoxy and hydroxyl groups into carboxyl functional groups. Subsequently, the GO-COOH solution was uniformly deposited on the graphene film to fabricate the GO-COOH/Graphene sensor. Under the test conditions of 100 ppm CH3CHO, the response of the GO-COOH/Graphene sensor was 86.29 times that of graphene and 5.44 times that of GO-COOH, with a response of 177.76 %, response time of 23 seconds, recovery time of 296 seconds, and theoretical limit of detection (LOD) is 42.3 ppb, indicating that the GO-COOH/Graphene sensor exhibits a rapid and highly sensitive response to CH3CHO at room temperature and high humidity. Additionally, the GO-COOH/Graphene sensor demonstrates outstanding selectivity, repeatability, and long-term stability in CH3CHO sensing. By capitalizing on the abundant functional groups of GO-COOH and the excellent electrical conductivity of graphene, the GO-COOH/Graphene sensor effectively resolves the issues of poor response, slow response, and slow desorption of graphene in CH3CHO sensing. The composite structure proposed in this work holds significant application potential in domains such as human respiratory detection and environmental monitoring of CH3CHO. © 2024 Elsevier B.V.