Different Roles of Fe1- xNixOOH Cocatalyst on Hematite (α-Fe2O3) Photoanodes with Different Dopants

Anton Tsyganok, Dino Klotz, Kirtiman Deo Malviya, Avner Rothschild, Daniel A. Grave

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)

Abstract

Transparent Fe1-xNixOOH overlayers (∼2 nm thick) were deposited photoelectrochemically on (001) oriented heteroepitaxial Sn- and Zn-doped hematite (α-Fe2O3) thin film photoanodes. In both cases, the water photo-oxidation performance was improved by the cocatalyst overlayers. Intensity modulated photocurrent spectroscopy (IMPS) was applied to study the changes in the hole current and recombination current induced by the overlayers. For the Sn-doped hematite photoanode, the improvement in performance after deposition of the Fe1-xNixOOH overlayer was entirely due to reduction in the recombination current, leading to a cathodic shift in the onset potential. For the Zn-doped hematite photoanode, in addition to a reduction in recombination current, an increase in the hole current to the surface was also observed after the overlayer deposition, leading to a cathodic shift in the onset potential as well as an enhancement in the plateau photocurrent. These results demonstrate that Fe1-xNixOOH cocatalysts can play different roles depending on the underlying hematite photoanode. The effect of the cocatalyst is not always limited to changes in the surface properties but may also cause an increase in hole current from the bulk to the surface that indicates a possible cross-link between surface and bulk processes.

Original languageEnglish
Pages (from-to)2754-2759
Number of pages6
JournalACS Catalysis
Volume8
Issue number4
DOIs
Publication statusPublished - Apr 6 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)

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