Room-temperature response of MOF-derived Pd@PdO core shell/γ-FeO microcubes decorated graphitic carbon based ultrasensitive and highly selective H gas sensor.

With the current upsurge in hydrogen economies all over the world, an increased demand for improved chemiresistive H sensors that are highly responsive and fast acting when exposed to gases is expected. Owing to safety concerns about explosive and highly flammable H gas, it is important to develop resistive sensors that can detect the leakage of H gas swiftly and selectively. Currently, interest in metal-organic frameworks (MOFs) for gas-sensor applications is increasing due to their open-metal sites, large surface area, and unique surface morphologies. In this research, a highly selective and sensitive H-sensor was established based on graphitic carbon (GC) anchored spherical Pd@PdO core-shells over γ-FeO microcube (Pd@PdO/γ-FeO@GC which is termed as S3) heterostructure materials. The combined solvothermal followed by controlled calcination-assisted S3 exhibited a specific morphology with the highest surface area of 79.12 m g, resulting in fast response and recovery times (21 and 29 s, respectively), and excellent sensing performance (ΔR/R∼ 96.2 ± 1.5), outstanding long-term stability, and a 100 ppb detection limit when detecting H-gas at room temperature (mainly in very humid surroundings). This result proves that adsorption sites provided by S3 can promote surface reactions (adsorption and desorption) for ultrasensitive and selective Hgas sensors.