Vanadium based zinc spinel oxides: Potential materials as photoanode for water oxidation and optoelectronic devices.

In the recent past, layered zinc-based vanadium spinel oxides (ZnVOs) have shown an intriguing way to accomplish the challenges of energy conversion, storage, and utilization issues. Here, through first-principles calculations, a comprehensive study has been carried out to investigate the AV 2 M (where A = Zn, Zn 2 , Zn 3 , Zn 4, and M = O 4 , O 6 , O 7 , O 8 , O 9 respectively) electronic, photocatalytic, and optical properties. Formation energies with a negative sign express that the final compounds from the pure elements are possible and cohesive energies revealed that compounds are energetically stable. Spin-polarized calculations are also taken into account for better approximation of the electronic properties (band structure and density of states). All layered structures show indirect bandgap for spin-up calculations in range 0.3 eV–2.4 eV, while spin-down calculations show mix trends in range 2.3 eV–3.50 eV. An appropriate band edge with large enough kinetic over-potentials of the oxygen evolution reaction (ΔE V ≥ 1.244 eV) makes them potential candidates as photoanode for water splitting. ZnV 2 O 4 is more suitable for OER as it has small kinetic overpotential as compared to the oxidation potential of water. Interestingly, all ZnVOs display a dramatically large coefficient (~105 cm−1) for optical absorption. Photogenerated electrons and holes on the layered zinc-based vanadium spinel oxide surfaces could make these spinel oxides promising materials for photocatalytic water splitting and solar energy conversion. [Display omitted] • Photocatalytic and optical properties of different phases of ZnVOs. • ZnVOs show good photocatalytic activity in visible and UV region. • ZnVOs could be potential candidates for water splitting (OER). • All ZnVOs display high coefficient of absorption (x 105 cm−1). • ZnVOs could be potential candidates for solar optical devices. [ABSTRACT FROM AUTHOR]