Abstract
A one-step colloidal synthesis of hierarchical nanoflowers of WS2 is reported. The nanoflowers were used to fabricate a chemical sensor for the detection of ammonia vapors at room temperature. The gas sensing performance of the WS2 nanoflowers was measured using an in-house custom-made gas chamber. SEM analysis revealed that the nanoflowers were made up of petals and that the nanoflowers self-assembled to form hierarchical structures. Meanwhile, TEM showed the exposed edges of the petals that make up the nanoflower. A band gap of 1.98 eV confirmed a transition from indirect-to-direct band gap as well as a reduction in the number of layers of the WS2 nanoflowers. The formation of WS2 was confirmed by XPS and XRD with traces of the oxide phase, WO3. XPS analysis also confirmed the successful capping of the nanoflowers. The WS2 nanoflowers exhibited a good response and selectivity for ammonia.
Highlights
Effective air quality management requires regular monitoring of both indoor and outdoor environments for the detection of harmful and toxic pollutants such as NH3
The gas sensing research community is putting a lot of effort into the research on other materials such as the transition metal dichalcogenides (TMDCs)
This feature of nanoflowers translates to a larger surface area, which is ideal for gas sensing
Summary
Effective air quality management requires regular monitoring of both indoor and outdoor environments for the detection of harmful and toxic pollutants such as NH3. High sensitivity and fast recovery to room temperature NH3 sensing and p-type character were shown by the hydrothermally prepared nanocomposite of Pt QDs/WS2 nanosheets [13]. Colloidal synthesis offers precise control of the reaction parameters in order to obtain desirable morphology It is catalyst-free, template-free, one-pot, scalable and short one-step synthesis at relatively low temperatures. It accommodates the use of a capping agent which offers protection of the nanoparticles against agglomeration [26], modifies the surface of the nanoparticles, may introduce new functionalities [27] and can influence the type of morphology formed [28]. Colloidal hierarchical nanoflowers of WS2 have not been synthesized for application in gas sensing
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