Dissociation reactions of hydrogen molecules at active sites on gold clusters: A DFT study

Small gold nanoparticles (GNPs) show special catalytic activity for hydrogen (H2) dissociation reaction, which is essential and important in understanding the hydrogen oxidation reaction in hydrogen energy source. To insight on catalytic properties of GNPs, we simulated H2 dissociation paths on neutral gold clusters (GCs) Aun (n = 1–6) and positively charged GCs Aun+ (n = 3–5), which are possible active sites on GNPs. The calculated results show that H2 dissociation on GCs follows a homolytic cleavage reaction process. Light irradiation and water environment are considered for H2 dissociation on Aunδ+ (n = 3–5, δ = 0 and +1) clusters. The calculated results show that when the incident light has a low energy close to the surface plasmon resonance (SPR) region of GNPs, the light can effectively reduce the H2 dissociation barrier, and an oxidation dissociation process is found for the water‐assisted H2 dissociation reaction. Gold nanoparticles (GNPs) show special catalytic activity for hydrogen (H2) dissociation reaction, and gold clusters (GCs) are used to describe the active sites of GNPs on DFT calculations, and the corner and edge sites of GCs have higher reaction activity than surface sites for H2 adsorption and dissociation process. The light and water can effectively reduce the H2 dissociation barrier.