Nanosheet assembled NiO-doped-ZnO flower-like sensors for highly sensitive hydrogen sulfide gas detection

Hydrogen sulfide (H2S) gas is a dual menace since it is not only hazardous to human health and the environment, but it is also flammable. Given these crucial considerations, the need for competent gas sensors for H2S detection becomes apparent. In this endeavor, an investigation of the gas-sensing prowess inherent in sensors made from assembled nanosheets of ZnO–NiO arranged into intricate flower-like structures. The sensing materials were prepared using a straightforward hydrothermal process. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to thoroughly examine the sensor's chemical properties and structural composition. The gas-sensing abilities of the sensing materials were rigorously assessed, which included a close examination of their electrical response to varied concentrations of H2S. The efficacy of the sensors may be due to the synergistic interactions between their distinct flower-like design, endowing them with an expansive surface area for optimum gas adsorption, and the significant catalytic impact supplied by the composition of ZnO–NiO. The results show that the ZnO–NiO flower-like sensors have high sensitivity, selectivity, and stability to H2S gas. Within the studied range, the response and recovery times were 51.43 s and 38.11 s respectively at 250 °C in 100 ppm H2S. This amalgamation of attributes manifests as an enhancement in the sensors' gas-sensing capabilities, highlighting their suitability for such an application. This research complements the explanation offered by first-principles calculations based on Density Functional Theory (DFT) to dive into the fundamentals of this gas-sensing mechanism.