Reduced graphene oxide/magnetite (rGO-Fe₃O₄) nanohybrids based selective room temperature H₂S gas sensor.

Metal oxide/reduced graphene oxide-based hybrids have been considered as efficient materials for the sensing of toxic gases like H₂S. However, these gas sensors are generally unable to perform at room temperature. In order to increase the gas sensing performance at room temperature (RT), in the present work Fe₃O₄ nanoparticles and rGO, having appropriate work function for the fabrication of p-n junction, have been employed to synthesize rGO-Fe₃O₄ nanohybrids. Thin films of the as-synthesized rGO-Fe₃O₄ nanohybrids and rGO have been fabricated for H₂S gas sensing applications. The effect of temperature on the sensing performance has also been examined by varying temperature from 22°C to 100°C. The maximum percentage response was observed at room temperature. This sensor showed high selectivity towards H₂S gas. It exhibited a very high response (40%) at 40 ppm H₂S gas as compared to other toxic gases such as CO, NH₃, and Cl₂. Even at 100 ppm of the toxic gases, a negligible response has been observed. The present work suggests that rGO-Fe₃O₄ nanohybrids to be an efficient sensing material for the fabrication of highly selective room temperature H₂S gas sensor.