Investigation into the enhanced gas sensing performance for CH4: Comparative study of MOF-derived and traditionally synthesized ZnCo2O4 flower based composite

Detecting very sensitive and selective methane (CH4) gas is very challenging and a major task in real-world situations. Herein, this work demonstrates a comparative analysis on the sensing performance between MOF-derived and conventionally prepared spinel-based nanocomposite for CH4 gas. Initially, ZnCo2O4 flower shaped spinel was synthesized via solvothermal route using ZIF-67 as template as well as conventional method using SDS. Both the ZnCo2O4 flower structure contains a lot of voids, making it easy for gases to diffuse while also allows a lot of sites for gas adsorption. Keeping an eye on this, a detailed study on the role of such factors for sensing performance of the sensor was presented utilizing both normally synthesized and MOF-derived rGO-ZnCo2O4 sensor. Interestingly, MOF-derived ZnCo2O4 flower has shown significantly higher response (S% = 3.2%) at 150 °C towards 100 ppm of CH4 as compare to conventionally prepared ZnCo2O4 flower (S% = 2.5%). Later on, the sensing ability of the designed 3DGO/MOF-derived ZnCo2O4 flower composite towards CH4 gas was also investigated carefully. The designed sensor exhibited a high response (5.1%) towards 100 ppm CH4 at room temperature with low response/recovery time (14 s/20 s) because of the presence of more number of oxygen defects in the composite (51.32%)