Hydrothermal synthesis of ZnO structures for formaldehyde sensing application

Document Type : Research Paper


Belgorod State University 85, Pobedy St., Belgorod, 308015, Russia


The article presents the hydrothermal methodology for the synthesis of ZnO nanostructures. Formaldehyde gas detection was investigated in the present study. The release of toxic and harmful gases seriously endangers human health and social and environmental safety. Sensitive determination of these gases is urgently needed to meet the demands of people and society. ZnO-based gas sensors have been widely used due to fast response, low detection limit, high selectivity, reliable performance and low manufacturing cost. In this review, we highlight the possible sensing mechanism of n-type ZnO materials, and discuss various strategies for enhancing sensitivity and selectivity of ZnO-based gas sensing materials, including regulation of the material morphology, composite of materials, photoexcitation, etc. Then, the current challenges of ZnO-based gas sensing materials are outlined, followed with the future research interests and directions of these materials. Gas-sensing measurements reveal that the sensor made of hexagonal ZnO rods exhibits a gas response of 37.8 and a response and recovery time of 9 and 11 s, respectively, to the formaldehyde gas of 50 ppm at an optimal temperature of 350 ºC.