Enhanced hydrogen gas sensing characteristics of graphene modified with rubidium (Rb)

Abstract In present work, the hydrogen gas sensing behaviour of graphene modified with rubidium (Rb-G) based sensor is reported. The Rb-G powders with 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 M M concentrations of Rb are synthesized by using wet-chemical route. The as-synthesized Rb-G powders are characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV–visible spectroscopy and photoluminescence spectroscopy. The XRD studies revealed the crystallization of Rb-graphene composite in as-synthesized Rb-G powders. The morphological analysis showed formation tightly packed sheets leading to spherical granules with increasing molar concentration of Rb in resultant Rb-G powders. The UV–visible and photoluminescence spectroscopic studies of as-synthesized Rb-G powders confirmed the addition of Rb within graphene sheets due to restoration of electronic conjugation leading to red shift. The gas sensing studies indicated the remarkable percentage sensitivity of 482 at considerably lower operating temperature of 348 K for the pellet sensor fabricated by using Rb-G powders obtained at 0.3 M concentrations of Rb. The gas sensing characterization proved the considerable repeatability and stability of this sensor with excellent selectivity towards hydrogen gas.