Low detection limit and high sensitivity NO₂ gas sensor based on PdO/NiMoO₄/NiO ternary composite materials

Area of Science:

• Materials Science
• Chemical Engineering
• Sensor Technology

Background:

• Developing effective nitrogen dioxide (NO2) gas sensors with high sensitivity, selectivity, and long-term stability is crucial for environmental monitoring and industrial safety.
• Existing sensor technologies often face limitations in achieving all these performance metrics simultaneously, hindering practical applications.

Purpose of the Study:

• To fabricate and characterize novel nanoflower-like PdO/NiMoO4/NiO ternary composites for NO2 gas sensing.
• To investigate the effect of tunable PdO loading on the sensor performance.
• To understand the underlying mechanisms responsible for the enhanced gas sensing properties.

Main Methods:

• Hydrothermal synthesis combined with in-situ impregnation and annealing was employed to create PdO/NiMoO4/NiO composites.
• The morphology and structure of the synthesized materials were characterized using relevant techniques.
• Gas sensing performance (response, selectivity, stability) was evaluated at various temperatures and concentrations.

Main Results:

• Nanoflower-like PdO/NiMoO4/NiO composites with tunable PdO loadings were successfully synthesized.
• The optimized sensor with 0.5 wt% PdO loading exhibited a 3.7-fold enhancement in response to 1 ppm NO2 at 160 °C compared to the unmodified sensor.
• The sensor demonstrated good selectivity and long-term stability, attributed to heterojunction effects and PdO catalytic activation.

Conclusions:

• The ternary PdO/NiMoO4/NiO composite offers a promising platform for developing high-performance NO2 gas sensors.
• Synergistic effects between the composite components and catalytic activation by PdO significantly improve charge transfer and surface reaction kinetics.
• The developed sensor shows considerable potential for practical and reliable NO2 detection applications.