Transition metal-decorated Zr12O12 nanocages as single-atom catalysts for water splitting: A first-principles study

Catalytic water splitting stands out as a highly promising approach to meet the growing global demand in the area of material sustainability. The challenging dissociation of H 2 O including adsorption-desorption of hydrogen remains a significant obstacle to improving the catalyst design and performance. In continuation of the effort to identify more effective and agile photocatalysts , Zr 12 O 12 and M@Zr 12 O 12 (M = Ti, V, Cr, or Mn) nanocages have been investigated using Density functional theory (DFT) calculations for their potential in overall catalytic water splitting applications. It has been observed that the M@Zr 12 O 12 nanocages demonstrate high stability, which is crucial in designing single-atom catalysts (SACs) to prevent possible aggregation of the metal. Electronic structure calculations reveal that metal atom loading reduces the bandgap of the Zr 12 O 12 nanocage, thereby increasing the visible light absorption of the catalysts. Additionally, the computed Gibbs free energies indicate that the Mn@Zr 12 O 12 nanocage exhibits a superior performance in hydrogen evolution and oxygen evolution reactions at room temperature among the M@Zr 12 O 12 catalysts explored. However, the oxygen evolution reaction does not proceed on the single metal atom loaded Ti@Zr 12 O 12 , V@Zr 12 O 12 and Cr@Zr 12 O 12 catalysts following the Rossmeisl mechanism, suggesting their use for other catalytic applications. • Transition metals (Ti, V, Cr, or Mn) are stable on Zr 12 O 12 nanocages and suitable for designing single-atom catalysts. • Design of Zr 12 O 12 nanocage significantly alters the electronic structure of ZrO 2 , reducing the bandgap to 2.07 eV. • Zr 12 O 12 and Mn@Zr 12 O 12 catalysts promote oxygen evolution reaction under the applied potential. • Mn@Zr 12 O 12 nanocage demonstrates superior hydrogen evolution performance compared to its counterparts.