Enhancement of H<inf>2</inf>S detection in impurity-doped graphene

Abstract

After the discovery of graphene, considerable researches have been studied to search its superior performance. In this work, the adsorption behaviors of sulfureted hydrogen (H2S) on pristine, tungsten (W), chromium (Cr) and copper (Cu)-doped graphene has been explored in this paper by the means of first-principles calculations based on density-functional theory (DFT). We have calculated the shortest distance between the gas molecule and doped atoms, transfer charge, adsorption energy, and density of states of systems. We get the conclusion that graphene dopes with transition metal will significantly modify the structure of pristine graphene. After the adsorption of H2S gas molecule, the doped transition metal atoms will remarkable protrude out of from plane layer which indicating the doped atoms have a substantial impact on the graphene. More surprisingly, tungsten and copper doped graphene exhibit a significantly high sensitive to the H2S gas molecule with a larger adsorption along with a evident charge transfer while the insensitive adsorption behaviors of H2S on graphene is observed in our calculation. To get a further insight into the interaction between H2S gas molecule and substrate, we also calculate the density of states; our simulation results demonstrate the presence of orbital hybridization between metal atoms and gas molecule, which further confirms the improvement of adsorption capability of graphene. Therefore, Graphene doped with tungsten and copper elements have a promising application prospect in the field of H2S gas sensor.