DFT and experimental investigations on the photocatalytic activities of NiO nanobelts for removal of organic pollutants - data

NiO nanobelts synthesized using the hydrothermal method are explored for photocatalytic degradation of organic pollutants like RhB, MO, MB, and CV. The XPS analysis confirmed the formation of the stoichiometric NiO nanobelts. Few micrometer long cubic crystalline NiO nanobelts of the average thickness of ~ 75 nm delivered a bandgap of 4.07 eV. The FTIR studies revealed that the mesoporous NiO nanobelts delivered stable photocatalytic activities after controlled irradiation under xenon lamp. The kinetic studies showed the 79.1, 82.7, 76.7, and 89 % degradation of MO, MB, CV, and RhB after 140 min. at the rate constants (k) of 0.007, 0.008, 0.009, and 0.012 min^-1, respectively. Complementary first-principles Density Functional Theory (DFT) and scavenging studies revealed the chemical picture and influence of the O2-, and photogenerated H+ from NiO nanobelts in the photocatalytic degradation of organic dyes. These studies corroborate the use of the NiO nanobelts in the stable and eco-friendly photocatalytic degradation activities of a wide range of organic pollutants.

Data underpinning the research are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 21 datasheets named after the Figure numbers in the published article.

Fig. 1. Rietveld refinement of XRD pattern of NiO nanobelts.
Fig. 2. Top view FESEM images showing the (a) porous network of (b) long-range NiO nanobelts. (c) EDS pattern of NiO nanobelt
Fig. 3. High-resolution XPS spectra of the (a) Ni(2p), and (b) O (1s) core levels of theNiO nanobelts. The XPS spectra were deconvoluted via Voigt fitting function within Shirley background.
Fig. 4. UV-Visible absorption spectra of NiO nanobelt. The inset figure shows the Tauc plot obtained from the absorption spectra
Fig. 5.UV-Visible absorption spectra of RhB dye solution collected at regular intervals for photocatalytic irradiation of 140 min in the presence of (a) 25, (b)40, and (c) 60 mg NiOnanobelts.
Fig. 6. (a) Histogram of degradation efficiency, and (b) kinetic curves and (c) corresponding pseudo-first-order kinetic plot evaluated for photocatalytically reduced RhB dye in the presence of NiO nanobelts at various irradiation time.
Fig. 7. Time-dependent UV-Visible absorption spectra of (a) MO, (b) CV, and (c) MB dye solutions collected at regular intervals for photocatalytic irradiation of 140 min in the presence of 60 mg NiO nanobelts.
Fig. 8. (a) Kinetic curves and (b) corresponding pseudo-first-order kinetic plot, and (c) histogram of degradation efficiency evaluated for photocatalytically reduced MO, CV,MB, and RhB dyes in the presence of 60 mg NiO nanobelts at various irradiation time
Fig. 9. FTIR spectra of pristine NiO nanobelts, RhB dye loaded NiO nanobelts, and NiO nanobelts extracted after photocatalytic degradation
Fig. 10.(a) PDOS of rock salt NiO (inset), (b) optimized surface structure of NiO(110)surface. The relaxed adsorption structures of O2adsorbed in (c) side-on and (d) end-on configurations, with the corresponding differential charge density iso-surface contours(e&f), where the green and yellow contours indicate electron density increase and decrease by 0.003 e/Å3, respectively. Blue and red atoms represent Ni and O, respectively.
Fig. 11. Effect of distinct scavengers on the photocatalytic degradation of MB using NiOnanobelts.
Fig. 12. Schematic of the photocatalytic degradation process of organic dyes using NiOnanobelts.