The hydrogen response of the Pd catalyst deposited on the pSiC
with different pore diameters of 25 nm and 60 nm is shown in Fig. 5.
The initial resistance varied depending on the pSiC pore diameter.
The hydrogen exposure time was fixed at 20 s. The hydrogen sensor
with the 25 nm pore diameter pSiC responded in real-time. The pSiC
substrate serves two purposes; it significantly increases the surface
area for adsorption of the gas and simultaneously increases the
baseline resistivity by creating pores. The Pd particles contact each
other when exposure to hydrogen significantly reduces the resistance
[3]. The resistance decreased with increasing hydrogen flow
and the response time (time to reach 90% of the maximum transition
value) was 10 s. After this point, the resistance became slowly
saturated. The resistance directly recovered to its initial value when