The
high demand for H2 gas sensors is not just limited to industrial
process control and leak detection applications but also extends to
the food and medical industry to determine the presence of various
types of bacteria or underlying medical conditions. For instance,
sensing of H2 at low concentrations (<10 ppm) is essential
for developing breath analyzers for the noninvasive diagnosis of some
gastrointestinal diseases. However, there are major challenges to
overcome in order to achieve high sensitivity and hence low limit
of detection (LoD) toward H2. In this study, it is demonstrated
that light-assisted amperometric gas sensors employing sensitive layers
based on Pd-decorated TiO2 long-range ordered crystals
can achieve excellent H2 sensing performance. This unique
combination of materials and novel layered structure enables the detection
of H2 gas down to 50 ppm with highly promising LoD capabilities.
The sensor response profiles revealed that the sensor’s signal-to-noise
ratio was higher in the presence of light when operated with a 9 V
bias (relative to other conditions used), producing a LoD of only
3.5 ppm at an operating temperature of 33 °C. The high performance
of the sensor makes it attractive for applications that require low-level
(ppm as opposed to conventional % levels) H2 gas detection.
Most importantly, the developed sensor exhibited high selectivity
(>93%) toward H2 over other gas species such as CO2, C4H8O, C3H6O,
CH3CHO, and NO, which are commonly found to coexist in
the environment.
We report enhanced amperometric sensing response of electrospun tungsten oxide (WO3-x) nanofibers towards acetone with low concentrations (1.2 – 12.5 ppm) at 350 ˚C. Scanning and transmission electron microscopy (SEM...
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