A density functional theory study on the H2S molecule adsorption onto small gold clusters

► The most favorable adsorption takes place between H2S and even-numbered Aun cluster. ► The small gold cluster would like to bond with sulfur. ► The Aun structures and H2S molecule still maintain their structural integrities. ► The reactivity enhancement of H2S and strong gold-sulfur bond are observed. ► The scalar relativistic effect is favorable to the adsorption.