Preparation of a high-performance H2S gas sensor based on CuO/Co3O4 composite derived from bimetallic MOF

Abstract

The bimetallic metal–organic frameworks (MOFs), Cu/Co-MOF, was synthesized through a solvothermal method and calcined to obtain CuO/Co3O4 composites. 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/Co3O4 composite 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/Co3O4 composite-based sensor is expected to find practical application in the low-power monitoring of H2S.