Palm Sugar-Induced Formation of Hexagonal Tungsten Oxide with Nanorod-Assembled Three-Dimensional Hierarchical Frameworks for Nitrogen Dioxide Sensing

Abstract

This work demonstrates the first utilization of natural palm sugar to induce the direct formation of hexagonal tungsten oxide (WO 3 ) with a hierarchical three-dimensional (3D) structure assembled by nanorods. The concentration of palm sugar controls the final phase and morphology of the WO 3 product. Lower concentrations of palm sugar favor the formation of hexagonal WO 3 with a nanorod-assembled hierarchical 3D morphology, while higher concentrations promote the formation of spherical monoclinic WO 3 particles. When employed for the sensing of toxic nitrogen dioxide (NO 2 ) gas, the hierarchical 3D hexagonal WO 3 particles exhibit a very high response to NO 2 gas at an optimum temperature of 250 °C, while also showing outstanding selectivity and stable responses toward NO 2 gas over a period of 24 days. The superior NO 2 sensing performance of these particles is attributed to the hierarchical 3D structure, which can offer more adsorption sites for NO 2 molecules, while the assembling nanorods may provide more effective diffusion and transport for the NO 2 molecules. Furthermore, the density functional theory (DFT) calculations reveal that NO 2 can gain more charge from hexagonal WO 3 than from monoclinic WO 3 upon adsorption, leading to a greater change in resistance.

A Novel Palm Sugar-Mediated Hydrothermal Synthesis of Spherical Tin Oxide for Enhanced SO2 Gas Detection

“…The calcination of SnO2 at 400°C leads to particle agglomeration due to the fusion of grain boundaries as the temperature increases [22], [23]. The formation of this spherical morphology is expected to be controlled by the presence of palm sugar, as it can act as a morphology controlling agent of metal oxide based sensor material [24]. This result provides novel insights into the use of palm sugar in SnO2 synthesis, which has not been previously reported.…”

2D/2D Nanostructured System Based on WO3/WS2 for Acetone Sensor and Breath Analyzer

“…1,2 Researchers in this field are continuously seeking more sensitive and precise detection techniques, measurement principles, and innovative analytical methodologies to develop modern sensing devices and instruments. 3,4 However, the majority of volatile organic compound (VOC) sensors on the market today provide data on total VOCs rather than individual VOC, and no sensor is available to work for biomedical-scale (lower concentrations) to industrial-scale (higher concentrations) applications, while selectivity is another issue that sensor technology faces. 5,6 Due to social expectations, critical sensor performance characteristics including sensitivity, selectivity, stability, and utility must be increased.…”

“…It is obvious that sensors that can deliver accurate timely information have a crucial role to play in limiting the transmission of viruses and diseases, thereby saving many lives, particularly during this period of sanitary emergency known as COVID-19. , Researchers in this field are continuously seeking more sensitive and precise detection techniques, measurement principles, and innovative analytical methodologies to develop modern sensing devices and instruments. , However, the majority of volatile organic compound (VOC) sensors on the market today provide data on total VOCs rather than individual VOC, and no sensor is available to work for biomedical-scale (lower concentrations) to industrial-scale (higher concentrations) applications, while selectivity is another issue that sensor technology faces. , Due to social expectations, critical sensor performance characteristics including sensitivity, selectivity, stability, and utility must be increased. Sensor response, selectivity, resolution, accuracy, and precision limits of sensing devices are constantly being increased. ,, Their use and application potential are also quickly growing at the same time.…”