First-Principles Study on the Structural Stability of Honeycomb Layered Nickel Tellurates

Honeycomb layered tellurates represent a burgeoning class of multi-functional materials with fascinating crystal-structural versatility and a rich composition space. Despite their multifold capabilities, their compositional diversity remains underexplored due to complexities in experimental design and syntheses. Thus, in a bid to expand this frontier, we employ a first-principles density-functional theory approach to predict $in$ $silico$ the crystal structures of new honeycomb layered tellurates embodied by the composition, $A\rm _2 Ni_2TeO_6$ ($A$ = alkali and coinage-metal atoms). Here alkali-metal atoms with vastly larger radii ($\rm Rb$ and $\rm Cs$) are found to engender a prismatic coordination with the oxygen atoms from the honeycomb slabs whilst coinage-metal atoms ($\rm Ag$, $\rm Au$ and $\rm Cu$) display a propensity for linear coordination. Further, the $\rm H_2 Ni_2TeO_6$ is found to also render a linear coordination wherein the hydrogen atom preferentially establishes a stronger coordination with one of the oxygen atoms to form hydroxyl groups. This work not only propounds new honeycomb layered tellurate compositions but also provides insight into the rational design of multifunctional materials for applications ranging from energy storage to catalysis and optics.