High performance room-temperature hydrogen sensor using MOF-derived porous Pd@SnO₂ composite

High performance room-temperature hydrogen (H₂) sensors are ideal for use in environments at risk of explosions. However, semiconductor chemi-resistive gas sensors typically require high operating temperatures, limiting their widespread applications. In this work, we developed a Pd-decorated porous SnO₂ hydrogen sensing material (Pd@SnO₂) using a facile solvothermal approach followed by the annealing of Sn-MOF. The resulting Pd@SnO₂ exhibits a porous granular structure with a high specific surface area of 47.7 m²/g, and a high concentration of oxygen vacancies (O_V) (36.3 %). The abundant gas diffusion channels and surface-active sites in Pd@SnO₂ facilitate the diffusion and absorption of hydrogen molecules while providing numerous Pd modification sites to lower the energy required for gas adsorption and activation. Through the synergy effects of these characteristics, the porous 13 wt% Pd@SnO₂ based hydrogen sensor presents significantly enhanced sensing performance for hydrogen detection at room temperature. It demonstrates an impressive sensing performance (Ra/Rg=25.4, 50ppm/25 ℃), outstanding long-term stability (over 21 days), and a detection limit of 1 ppm. Up to now, the Pd@SnO₂ synthesized in this work displayed a higher response at room temperature than previously reported SnO₂ based H₂ sensors. This work may serve as a reference for the future design of room-temperature hydrogen detectors.