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Influence of anodization time on the surface modifications on α-Fe2O3 photoanode upon anodization

Abstract

In searching for a suitable semiconductor material for hydrogen production via photoelectrochemical water splitting, α-Fe2O3 received significant attention as a promising photoanode due to its band gap (∼2.1 eV), good stability, low cost, and natural occurrence. α-Fe2O3 thin films were prepared by economic and facile dip coating method and subsequently subjected to an anodic potential of 700 mV versus Ag/AgCl in 1M KOH for different anodization times (1, 10, and 900 min) under illumination. X-ray diffractometry revealed increase in crystallites size from ∼31 nm for nanoparticles in pristine state to ∼38 and 44 nm after anodization for 1 and 900 min, respectively. A clear positive correlation between anodization time and grain (particle) size was observed from field emission gun scanning electron microscopy and atomic force microscopy (AFM); longer exposure time to anodizing conditions resulted in larger grains. Grain size increased from ∼57.9 nm in pristine state to ∼153.5 nm after anodization for 900 min. A significant smoothening of the surface with increase in anodization time was evident from AFM analysis.

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ACKNOWLEDGMENT

This study was supported by Swiss-South African Joint Research (SSAJR) Project IZLSZ2-149031; the Swizz SNF grant R’Equip 206021-121306 and National Research Foundation of South Africa (NRF). K.M acknowledges University of Botswana for financial support. Y.H is grateful for financial support from and SNF Project No. 132126.

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Correspondence to Kelebogile Maabong or Mmantsae Diale.

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This author was an editor of this journal during the review and decision stage. For the JMR policy on review and publication of manuscripts authored by editors, please refer to http://www.mrs.org/jmr-editor-manuscripts/.

A previous error in this article has been corrected, see 10.1557/jmr.2016.229.

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Maabong, K., Hu, Y., Braun, A. et al. Influence of anodization time on the surface modifications on α-Fe2O3 photoanode upon anodization. Journal of Materials Research 31, 1580–1587 (2016). https://doi.org/10.1557/jmr.2016.53

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