Preparation of a high-performance H 2 S gas sensor based on CuO/Co 3 O 4 composite derived from bimetallic MOF.

The bimetallic metal-organic frameworks (MOFs), Cu/Co-MOF, was synthesized through a solvothermal method and calcined to obtain CuO/Co 3 O 4 composites. By adjusting the molar ratio between Cu and Co ions, a composite material of CuO/Co 3 O 4 (Cu:Co = 1:1) was developed and showed excellent sensing capabilities, and the response reached as high as 196.3 for 10 ppm H 2 S detection. Furthermore, the optimal operating temperature as low as 40 °C was found. In comparison with the sensors prepared by pristine CuO and pristine Co 3 O 4 , the sensor based on CuO/Co 3 O 4 composite exhibited a significant response. Additionally, the sensor can detect H 2 S 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 Co 3 O 4 . The as-prepared CuO/Co 3 O 4 composite-based sensor is expected to find practical application in the low-power monitoring of H 2 S.