Understanding the electronic metal-support interactions of the supported Ni cluster for the catalytic hydrogenation of ethylene

The electronic metal-support interaction (EMSI) has a very profound impact on the catalytic activity of supported catalysts. In this paper, density functional theory calculations were utilized to understand the effect of EMSI between Ni cluster (Ni4) and three substrates (CeO2, TiO2, and BNO) on the catalytic hydrogenation of ethylene. When Ni cluster was anchored on the surface of support, visibly electron transfer from Ni to substrate was observed, leading to positively charged Ni clusters with the sequence of Ni4/TiO2 > Ni4/CeO2 > Ni4/BNO. During the ethylene hydrogenation reaction, the electron rich Ni4/BNO exhibits superior performance in activating of both H2 and ethylene molecules, while the electron deficient Ni4/TiO2 shows the worst activation among the three catalysts. As a consequence, the activation energies of ethylene hydrogenation follow the same sequence of the charge state on the supported Ni clusters at both low and high H coverages. Our results suggest that the EMSI between metal nanoparticles and support materials is capable of tuning the charge state and electron density of supported metals, which further determines the activity of the catalyst. This work provides a potential approach for design new catalysts with desired activity by utilizing appropriate support materials.