Water Adsorption and Dissociation on Ni₃ and Ni₅ Decorated Y- and Sc-stabilized Zirconia: Insights from Density Functional Theory Investigation

Abstract

In this work, water adsorption and dissociation on Ni₃- and Ni₅-decorated Y- and Sc-stabilized zirconia (YZO and ScZO respectively), were probed using planewave, pseudopotential-based density functional theory calculations, to assess water splitting and subsequent hydrogen evolution potential of these metal-on-zirconia structures. It is found that the strength of Ni cluster binding on zirconia depends on the size of the cluster, at least for Ni₃ and Ni₅, and on the nature of the stabilizing atom. The Ni₃ and Ni₅ clusters tend to bind more favorably on the Sc site of ScZO compared to that of the Y site of YZO. Water is found to adsorb strongly on Ni₃-YZO, Ni₃-ScZO, and Ni₅-ScZO. Water dissociation barrier for both the first and second hydrogen atoms tends to decrease for larger Ni cluster, with the Ni₅-YZO system giving the lowest energy barriers. With relatively fine dissociation barriers, such systems could potentially be tapped for electrocatalytic water dissociation reactions leading to hydrogen evolution. These results are of importance and could contribute significantly in the further search and design of electrocatalytic materials for water dissociation and eventual hydrogen evolution for sustainable hydrogen production.