Activation of Ni2V2O7to nonstoichiometric NiV3O8for solar-driven photoelectrochemical water oxidation

Abdul Zeeshan Khan, Ibrahim Khan, Ali Sufyan, Dalaver Anjum, Ahsanulhaq Qurashi

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Hydrogen treatment is an effective strategy to introduce non-stoichiometry and improve the performance of semiconductor nanomaterials for photocatalytic applications. Herein, for the first time, we report the hydrogen treatment activation of non-photoactive nickel vanadate (NV) towards photoelectrochemical (PEC) water oxidation. The NV nanostructures are synthesized by a sonication-assisted hydrothermal method. Hydrogen-treated nickel vanadate (H-NV) nanoflakes were achieved by subjecting the NV to anneal at 350 °C for 4 h in a hydrogen atmosphere. Field emission scanning electron microscopy (FESEM), and High resolution transmission electron microscopy (HRTEM) indicates irregular network morphology for the as-synthesized NV nanostructures, calcined at 500 °C (NV-500). The XRD pattern confirms monoclinic and orthorhombic crystal phases for NV-500 and hydrogen treated nickel vanadate (H-NV-500), respectively. The defects states produced on the surface of NV-500 after high dose of electrons which implies the creation of oxygen vacancies and consistent with the XPS analysis for H-NV-500. The optical properties of H-NV-500 via UV-Vis/DRS show significant absorption in the visible regime at ? = 628 nm with an indirect bandgap value of 2.15 eV from Tauc's plot and supports by density functional theory (DFT) studies. The PEC water oxidation performance has onset potential at ~0.74 V. The photocurrent density at saturation is ~2.13 µA/cm2 for H-NV-500 photoanode. These results suggest that hydrogen treatment effectively activated NV towards PEC water oxidation process, which was initially inactive.

Original languageBritish English
Article number105526
JournalJournal of Environmental Chemical Engineering
Volume9
Issue number4
DOIs
StatePublished - Aug 2021

Keywords

  • DFT calculations
  • Hydrogen treated nickel vanadate
  • Nickel vanadate
  • Photoelectrochemical water splitting
  • Water oxidation

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