Preparation of a high-performance H₂S gas sensor based on CuO/Co₃O₄composite derived from bimetallic MOF

The bimetallic metal-organic frameworks (MOFs), Cu/Co-MOF, was synthesized through a solvothermal method and calcined to obtain CuO/Co₃O₄composites. By adjusting the molar ratio between Cu and Co ions, a composite material of CuO/Co₃O₄(Cu:Co = 1:1) was developed and showed excellent sensing capabilities, and the response reached as high as 196.3 for 10 ppm H₂S detection. Furthermore, the optimal operating temperature as low as 40 °C was found. In comparison with the sensors prepared by pristine CuO and pristine Co₃O₄, the sensor based on CuO/Co₃O₄composite exhibited a significant response. Additionally, the sensor can detect H₂S gas down to 300 ppb. The gas sensing mechanism is discussed in depth from the perspective of p-p heterojunction formation between the p-type CuO and p-type Co₃O₄. The as-prepared CuO/Co₃O₄composite-based sensor is expected to find practical application in the low-power monitoring of H₂S.