RESUMO
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.
RESUMO
MXene, a class of two-dimensional materials that are emerging as rising stars in the field of materials, are receiving much attention in sensing. Ti3C2TxMXene, the most maturely researched MXene, is widely used in energy, biomedical, laser, and microwave shielding applications and has also been expanded to gas sensing and wearable electronics applications. Compared with Ti3C2Tx, Nb2CTxMXene is more difficult to etch and has higher resistances at room temperature; so, few studies have been reported on their use in the sensing field. Based on the preparation of few-layer Nb2CTxMXene by intercalation, this study thoroughly examined their gas-sensing properties. The successfully prepared few-layer Nb2CTxshowed good selectivity and high sensitivity to triethylamine at room temperature, with response values up to 47.2% for 50 ppm triethylamine and short response/recovery time (22/20 s). This study opens an important path for the design of novel Nb-based MXene sensors for triethylamine gas detection.