Unveil the potential in hydrogen activation and spillover towards NiMoS by Ni3S2 - A theoretical study

Abstract

Using density functional theory calculation (DFT) as well as ab initio molecular dynamics (AIMD) simulation, the capabilities of hydrogen dissociation and hydrogen spillover over Ni3S2 (111) surface are examined. The steady state, energy change, transition state of hydrogen dissociation and the spillover pathway, stability of S-H bond during hydrogen spillover are all calculated. The results show that several S-top site and S-Ni-bridge site are available for dissociation, among them, “S1-top”, “S3-top” and “S1-Ni1” sites could be recognized as distinct sites, and one hydrogen molecule could be efficiently dissociated by one S3-top site and the adjacent S1-Ni1 site. The crystal orbital Hamilton population analysis and AIMD simulation for S-H bonds both confirm the tendency towards breaking, then the spillover coordinate calculation gives a self-consistent pathway among three district sites. In short, the Ni3S2 surface shows excellent performance in the aspect of hydrogen dissociation and hydrogen spillover, which displays tremendous potential for hydrogen spillover in NiMoS catalytic system. We hope these findings could shed light on the theory of “remote control” model.