Correlation between microstructural defects and photoelectrochemical performance of 1D Ti--Nb composite oxide photoanodes for solar water splitting

Author's Department

Physics Department

Second Author's Department

Physics Department

Third Author's Department

Physics Department

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https://www.sciencedirect.com/science/article/abs/pii/S0360319919328629

All Authors

Aya A Saleh; Mahmoud Farag; Nageh K Allam

Document Type

Research Article

Publication Title

International Journal of Hydrogen Energy

Publication Date

12-31-2019

doi

10.1016/j.ijhydene.2019.07.219

Abstract

We report on the optimized fabrication of ultrathin wall nanotubes grown on Ti–Nb alloy via anodization in organic-based electrolytes. The nanotubes are vertically aligned with wall thicknesses of 5–8 nm, diameters of 180–200 nm, and lengths of 2–2.8 μm. Raman spectroscopy and glancing angle x-ray diffraction (GAXRD) measurements indicated the formation of composite oxides of anatase TiO2 and monoclinic Nb2O5. The composite oxides showed better stability at elevated temperatures up to 650 ᵒC and with much smaller induced microstrain compared to the TiO2 counterpart. X-ray photoelectron spectroscopy (XPS) analysis confirmed the composition of the fabricated nanotubes as a mixed TiO2–Nb2O5 composite. Upon their use as photoanodes to split water, the composite TiO2–Nb2O5 NTs showed almost 2-fold increase in the obtained photocurrent compared to that of bare TiO2 NTs prepared under the same conditions. Moreover, the incident photon to current efficiency (IPCE) of the mixed oxide nanotubes was higher than that of bare TiO2 with a positive shift towards longer wavelengths, indicating improved electron mobility and charge collection. Hence, the addition of Nb resulted in the formation of thermally stable and photoactive photoanodes for solar fuel production.

First Page

24418

Last Page

24429

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