▎ 摘　　要

As one of the most explored carbon nanostructures, graphene has spurred research in building of diverse sensing platforms for various targets (including formaldehyde (FA)) due to the unique electrical/optical properties. Unlike most other nanomaterial-based sensors, graphene-based sensors show distinctive advantages to operate under ambient conditions. To review graphene sensors in detail, we divided them into three classes: those based on pristine, functionalized, or composite forms of graphene. The synergistic interactions of its nanostructured composites (with metals, metals oxides, semiconductor nanostructures, polymers, etc.) have helped them improve the sensing performance substantially. In this review article, we provide a detailed discussion of the development of graphene-based formaldehyde sensors. We evaluate the performance of the three different classes of graphene-based structures in terms of operational parameters, sensing range, detection limit, sensitivity, response time, and recovery time. We conclude this review with challenges and future directions for graphene-based formaldehyde sensors. (c) 2019 Elsevier B.V. All rights reserved.