Effect of Boron Doping on the Structure and Band Gap of ZnO Nanowires Grown by Anodizing: Toward Water Splitting Applications

Document Type : Research Paper

Authors

Department of Materials Engineering, Faculty of Mechanical Engineering, University of Tabriz, Tabriz 51666–16471, Iran

10.22059/jufgnsm.2025.02.09

Abstract

Zinc oxide (ZnO) nanowires are promising for solar-driven hydrogen production, but their wide band gap (≈3.3 eV) limits absorption to the ultraviolet (UV) region. This study investigates the effect of boron (B) doping on the structural and optical properties of ZnO nanowires to enhance their photocatalytic potential. ZnO nanowires were synthesized by anodizing high-purity zinc foil in a sodium bicarbonate/ethylene glycol electrolyte at 5 V and 29 °C for 40 min under ambient pressure, followed by annealing at 200 °C. Boron doping was performed by immersion in boric acid (0.025–0.1 M) for 1–10 h, followed by annealing at 250 °C. Characterization using field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and diffuse reflectance spectroscopy (DRS) revealed that boron content increased from 0 at.% to 23.02 at.% with immersion time and varied from 8.22 at.% to 14.87 at.% with boric acid concentration. Doping increased nanowire diameter from 65.3 nm to 113.8 nm (≈74.4%) and length from 4.63 µm to 4.85 µm (≈4.7%), while reducing the surface-to-volume ratio by ≈36.6%. The optical band gap decreased up to ≈24.2%, enhancing visible-light absorption. These results demonstrate that boron-doped ZnO nanowires exhibit improved light harvesting and structural properties, making them efficient candidates for photocatalytic and photoelectrochemical hydrogen generation under solar illumination.

Keywords

References

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Journal of Ultrafine Grained and Nanostructured Materials
Volume 58, Issue 2
December 2025
Pages 242-254

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History

  • Receive Date: 01 August 2025
  • Revise Date: 03 October 2025
  • Accept Date: 08 October 2025

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