Ultra-Low Loading Single-Atom Pt-Decorated SnO₂ for High-Performance MEMS Hydrogen Sensor

Developing high-response, low-cost H₂ sensors is critical for real-time H₂ monitoring in the new energy era. In this work, ultra-low content (0.07 wt%) single-atom Pt-loaded SnO₂/MEMS H₂ sensors were prepared by an extended two-step annealing method, enabling ppb-level H₂ sensing with low power consumption. At the optimal operating temperature of 201 °C, the sensor showed a response of 55.0 to 100 ppm H₂, which is 9.17 times that of the pure SnO₂ sensor. Compared with SnO₂ sensors loaded with Pt via traditional impregnation, its optimal operating temperature is reduced by nearly 30 °C, and its response value is increased by 45.0. Additionally, the sensor exhibited a fast response time of 2.3 s and a limit of detection as low as 36 ppb. Mechanistic studies reveal that,, compared to traditional nanoparticle-modified material, the single-atom Pt-modified material exhibits a higher adsorbed oxygen content and enhanced surface oxidation activity. These results indicate single-atom Pt enhances the active oxygen level, underscoring its critical role in boosting H_2-sensing performance.