One-step synthesis of flower-shaped WO3 nanostructures for a high-sensitivity room-temperature NOx gas sensor

Abstract

In this work, we report a one-step synthesis of spherical flower-shaped tungsten oxide (WO₃) nanostructures by using polyethylene glycol (PEG) as a surfactant. The PEG played a crucial role in controlling the final morphology of the WO₃ product. The structure and morphology of the product were characterized by carrying out XRD and SEM experiments. These characterizations indicated these three-dimensional flower-shaped nanostructures to be well crystallized, to have a uniform morphology with an average diameter of 3 μm, and to consist of many two-dimensional nanosheets. The flower-shaped WO₃ particles exhibited excellent room-temperature NO_x gas-sensing performance, including a sensitivity as high as 80%, a short response time of 4.5 s to 97 ppm NO_x, and a low detection limit of 970 ppb. The excellent performance was due to the structure and morphology of the WO₃ product.