Atomic Surface Engineering of MXene for Stable Hydrogen Sensing at Low Temperature

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Two-dimensional (2D) materials like MXenes offer great potential for gas sensing due to their conductivity and surface properties.
• MXene sensors face challenges with oxidative degradation, limiting their practical application.
• Developing stable and efficient MXene-based sensors is crucial for applications like hydrogen safety.

Purpose of the Study:

• To develop a surface engineering strategy for MXene gas sensors to improve stability and performance.
• To create a robust MXene sensor for room-temperature hydrogen detection using atomic layer deposition (ALD).
• To investigate the synergistic effects of ZnO and Pd coatings on MXene for enhanced gas sensing.

Main Methods:

• Atomic layer deposition (ALD) was used to coat Ti3C2Tx MXene with ZnO and Palladium (Pd).
• Density functional theory (DFT) calculations were employed to understand the catalytic mechanisms.
• Gas sensing performance was evaluated at room temperature for hydrogen detection.

Main Results:

• The Pd-ZnO/MXene sensor demonstrated excellent room-temperature hydrogen sensing with rapid response (23 s) and recovery (64 s) for 50 ppm H2.
• The ZnO layer effectively protected the MXene from oxidation while allowing charge transport.
• DFT confirmed the bifunctional catalytic role of Pd in H2 dissociation and facilitated O2 adsorption/dissociation on ZnO.

Conclusions:

• ALD-based surface engineering provides a universal platform for creating stable and high-performance MXene sensors.
• The developed Pd-ZnO/MXene sensor significantly outperforms existing MXene-based sensors for hydrogen detection.
• This approach advances the real-world deployment of MXene sensors in hydrogen safety and clean energy.