1 research outputs found
Three-Dimensional Assemblies of Edge-Enriched WSe<sub>2</sub> Nanoflowers for Selectively Detecting Ammonia or Nitrogen Dioxide
Herein, we present, for the first time, a chemoresistive-type
gas
sensor composed of two-dimensional WSe2, fabricated by
a simple selenization of tungsten trioxide (WO3) nanowires
at atmospheric pressure. The morphological, structural, and chemical
composition investigation shows the growth of vertically oriented
three-dimensional (3D) assemblies of edge-enriched WSe2 nanoplatelets arrayed in a nanoflower shape. The gas sensing properties
of flowered nanoplatelets (2H-WSe2) are investigated thoroughly
toward specific gases (NH3 and NO2) at different
operating temperatures. The integration of 3D WSe2 with
unique structural arrangements resulted in exceptional gas sensing
characteristics with dual selectivity toward NH3 and NO2 gases. Selectivity can be tuned by selecting its operating
temperature (150 °C for NH3 and 100 °C for NO2). For instance, the sensor has shown stable and reproducible
responses (24.5%) toward 40 ppm NH3 vapor detection with
an experimental LoD < 2 ppm at moderate temperatures. The gas detecting
capabilities for CO, H2, C6H6, and
NO2 were also investigated to better comprehend the selectivity
of the nanoflower sensor. Sensors showed repeatable responses with
high sensitivity to NO2 molecules at a substantially lower
operating temperature (100 °C) (even at room temperature) and
LoD < 0.1 ppm. However, the gas sensing properties reveal high
selectivity toward NH3 gas at moderate operating temperatures.
Moreover, the sensor demonstrated high resilience against ambient
humidity (Rh = 50%), demonstrating its remarkable stability toward
NH3 gas detection. Considering the detection of NO2 in a humid ambient atmosphere, there was a modest increase
in the sensor response (5.5%). Furthermore, four-month long-term stability
assessments were also taken toward NH3 gas detection, and
sensors showed excellent response stability. Therefore, this study
highlights the practical application of the 2H variant of WSe2 nanoflower gas sensors for NH3 vapor detection