Pd@TiO2 Core-Shell Nanoparticles Supported by Graphite Carbon Nitride Nanosheets as a Sensitive Ethanol Sensor

Herein, we report the construction of a sensitive ethanol sensor based on palladium (Pd)@ titanium oxide (TiO
₂
) core-shell nanoparticles supported by graphite carbon nitride (g-C
₃
N
₄
) nanosheets synthesized by the combination of the facile hydrothermal process and calcination method. The structural and morphological features of the synthesized material were characterized. Transmission electron microscopy analysis showed that the Pd nanoparticles as cores are surrounded by TiO
₂
shell and anchored onto the g-C
₃
N
₄
nanosheets. The response of the sensor towards ethanol was examined by electrical resistance measurement. The results of gas sensing performance reveal that the Pd@TiO
₂
/g-C
₃
N
₄
sensor has a great response to ethanol at a low operating temperature of 125°C with a response and recovery times of about 30 s and 15 s, respectively. It was observed that the response of the sensor increased almost linearly with increasing ethanol concentration from 50 ppm to 1000 ppm. The high response of Pd@TiO
₂
/g-C
₃
N
₄
can be ascribed to the Schottky junction formed between the Pd and TiO
₂
and the high surface area of g-C
₃
N
₄
.