Rh-Induced Oxygen Vacancies in a PdRh/SnO₂ Heterointerface for Enhanced MEMS Hydrogen Detection

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• High-performance hydrogen (H2) sensors are crucial for industrial safety and environmental monitoring.
• Existing sensors often face limitations in response, speed, and detection limits.

Purpose of the Study:

• To develop a microelectromechanical system (MEMS) hydrogen sensor with enhanced performance.
• To investigate the sensing mechanisms behind the performance improvements.

Main Methods:

• Fabrication of a MEMS sensor using SnO2 nanoflowers decorated with PdRh nanoparticles.
• Gas-sensing evaluations to assess response, kinetics, and detection limits.
• Mechanistic studies combining experimental data and density functional theory (DFT) calculations.

Main Results:

• The PdRh/SnO2 sensor achieved an ultrahigh response (20.2 to 100 ppm H2), a ~4-fold enhancement over Pd/SnO2.
• Rapid response (1.7 s) and recovery (2.2 s) times were observed.
• A low detection limit (<100 ppb) and good long-term stability were demonstrated.
• DFT calculations revealed Rh-mediated defect engineering (oxygen vacancies) as a key factor.

Conclusions:

• The synergistic effect of PdRh nanoalloy and Rh-induced defect engineering in SnO2 significantly enhances H2 sensing performance.
• The developed MEMS sensor shows great potential for practical H2 detection applications.
• Integration into a portable wireless monitoring system validates its real-world applicability.