Highly Dispersed Pt-Decorated Oxygen-Vacancy-Rich MOF-Derived SnO2 Nanostructures on MEMS Hot Plate for ppb-Level Hydrogen Detection

With the rapid development of the hydrogen energy economy, there is an increasingly urgent demand for low-power-consumption and integrable sensors capable of accurate and real-time monitoring of hydrogen (H2). In this study, SnO2 nanoparticles rich in oxygen vacancies were successfully prepared via a metal–organic framework (MOF)-derived method. Based on this, highly dispersed Pt-modified SnO2 nanoparticles were fabricated using a two-step annealing method, and a MEMS H2 sensor with high response and low power consumption was developed. Studies have shown that the 0.5%Pt-SnMOF/600-SnO2 sensor exhibits a high response of 31.5 to 100 ppm of H2 at an operating temperature of 201 °C, which is 2.7 times that of the SnMOF/600-SnO2 sensor (with an optimal operating temperature of 244 °C), and its power consumption is only 22.1 mW. Furthermore, this sensor demonstrates excellent comprehensive performance, including an extremely low limit of detection of 73.6 ppb, outstanding selectivity, and good long-term stability. Mechanistic studies indicate that the enhancement of gas-sensing performance is due to a combination of factors: plentiful oxygen vacancies, the role of Pt in promoting oxygen reactions, and its effect on the material’s electronic properties.