Effect of core and surface area toward hydrogen gas sensing performance using Pd@ZnO core-shell nanoparticles

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Hydrogen gas sensors are crucial for safety and industrial process monitoring.
• Palladium (Pd) and zinc oxide (ZnO) are known for their catalytic and semiconducting properties, respectively.
• Core-shell nanostructures can enhance material properties through synergistic effects.

Purpose of the Study:

• To fabricate and characterize Pd@ZnO core-shell nanoparticles (CSNPs) for hydrogen gas sensing.
• To investigate the effect of palladium core oxidation state on hydrogen sensing performance.
• To optimize the synthesis of CSNPs for enhanced gas sensing capabilities.

Main Methods:

• Hydrothermal synthesis of Pd@ZnO CSNPs.
• Calcination of CSNPs in different atmospheres (argon and air).
• Gas sensing measurements at 350°C to detect 100 ppm hydrogen.
• Analysis of material composition and surface area (BET).

Main Results:

• The Pd@ZnO-2 sensor (calcined in argon) exhibited the highest response (22), significantly outperforming Pd@ZnO-1 (12) and pure ZnO (7).
• Pd@ZnO-2 demonstrated faster response (1.4 min) and recovery (7.8 min) times compared to other sensors.
• High metallic Pd0 content (77%) in Pd@ZnO-2, attributed to argon calcination, enhanced sensing activity and selectivity.

Conclusions:

• Argon calcination preserves metallic Pd0, leading to superior hydrogen sensing performance in Pd@ZnO CSNPs.
• Pd@ZnO CSNPs offer a promising platform for developing highly sensitive, selective, and fast-acting hydrogen gas sensors.
• The high BET surface area of the core-shell structure contributes to efficient gas-sensing reactions.