Paper-Based Hydrogen Sensors Using Ultrathin Palladium Nanowires

Area of Science:

• Materials Science
• Chemical Engineering
• Sensor Technology

Background:

• Hydrogen (H₂) is a clean energy carrier with high energy density, necessitating efficient detection systems.
• Paper is a sustainable material suitable for flexible electronics.
• Current H₂ sensors often face limitations in speed, cost, or sensitivity.

Purpose of the Study:

• To develop a fast, low-cost, and sensitive room-temperature H₂ sensor.
• To investigate the sensing mechanism using palladium nanowires (PdNWs) on a paper substrate.
• To compare the performance of polycrystalline and quasi-single-crystalline PdNWs for H₂ detection.

Main Methods:

• Fabrication of ultrathin palladium nanowires (PdNWs) on a paper substrate.
• Room-temperature H₂ gas sensing measurements.
• Comparative analysis of polycrystalline and quasi-single-crystalline PdNW sensor performance.
• Evaluation of sensor selectivity, stability, and limit of detection.

Main Results:

• Polycrystalline PdNWs demonstrated a 4.3% response to 1 vol% H₂ with rapid response (4.9 s) and recovery (10.6 s) times.
• Quasi-single-crystalline PdNWs showed a higher response (8%) but slower kinetics.
• The polycrystalline PdNW sensor achieved a limit of detection of 10 ppm H₂ in air with excellent selectivity and stability.
• The sensor exhibits significantly lower cost compared to existing technologies.

Conclusions:

• Ultrathin polycrystalline PdNWs on paper enable high-performance, room-temperature H₂ sensing.
• The sensor's fast response is attributed to synergistic effects including ultrasmall diameter and unique surface properties.
• This paper-based sensor represents a significant advancement towards practical, affordable H₂ detection systems.