An All-Organic Polydopamine/Poly(heptazine imide) Heterojunction for High-Sensitivity Photoelectric H₂ Detection at...

Area of Science:

• Materials Science
• Chemical Sensing
• Nanotechnology

Background:

• Highly sensitive photoelectric detection of hydrogen (H2) at room temperature (RT) is crucial for various applications.
• Improving charge transfer and oxygen (O2) adsorption is key to enhancing the generation of superoxide radicals (•O2−) for gas sensing.

Purpose of the Study:

• To construct a novel all-organic polydopamine/poly(heptazine imide) (PDA/PHI) nanosheet heterojunction for photoelectric H2 detection.
• To investigate the performance and sensing mechanism of the PDA/PHI heterojunction for H2 detection at RT.

Main Methods:

• In situ polymerization to synthesize PDA/PHI nanosheet heterojunctions.
• Photoelectric detection under 405 nm irradiation at RT.
• Dynamic detection process analysis.
• In situ μs-transient absorption spectroscopy to study charge transfer dynamics.

Main Results:

• The optimized PDA/PHI heterojunction exhibited high sensitivity with an ultralow detection limit of 500 ppm and a high gas response of 42.8% for 5000 ppm H2.
• Good linearity, repeatability (40 cycles), long-term stability (>210 days), and high selectivity were confirmed.
• Efficient Z-scheme charge transfer and promoted O2 adsorption facilitated •O2− generation, leading to outstanding performance.

Conclusions:

• The all-organic PDA/PHI heterojunction demonstrates significant potential for RT photoelectric H2 detection.
• The study provides deep insights into the role of •O2− species and charge transfer in gas sensing properties.
• This work highlights the promise of all-organic heterojunctions for advanced gas sensing technologies.