Formaldehyde sensors are essential devices in the indoor air quality monitoring and gas leakage detection in industrial areas. Enormous efforts are made to promote the development of sensitive formaldehyde sensors with fast response and recovery, low manufacture cost, low energy consumption and long work life. The progress in fundamental research of metal oxide semiconductors (MOS) nanomaterials has enabled significant development of high performance formaldehyde sensors. This review focuses on the most recent advances of formaldehyde sensors utilizing MOS nanostructures. The design and synthesis principles of MOS nanostructures that hold a great potential for real sensor applications have been summarized. Particular emphasis is given to the structure–property relationships of some typical n-type and p-type MOS for efficient detection of formaldehyde. The optimization strategies to enhance the formaldehyde sensor performances are also discussed. Finally, we discuss the perspectives and challenges in the future development of the formaldehyde sensors.
