Two-site H2O2 photo-oxidation on haematite photoanodes

Yotam Y. Avital, Hen Dotan, Dino Klotz, Daniel A. Grave, Anton Tsyganok, Bhavana Gupta, Sofia Kolusheva, Iris Visoly-Fisher, Avner Rothschild, Arik Yochelis

研究成果: Contribution to journalArticle査読

7 被引用数 (Scopus)

抄録

H2O2 is a sacrificial reductant that is often used as a hole scavenger to gain insight into photoanode properties. Here we show a distinct mechanism of H2O2 photo-oxidation on haematite (α-Fe2O3) photoanodes. We found that the photocurrent voltammograms display non-monotonous behaviour upon varying the H2O2 concentration, which is not in accord with a linear surface reaction mechanism that involves a single reaction site as in Eley–Rideal reactions. We postulate a nonlinear kinetic mechanism that involves concerted interaction between adions induced by H2O2 deprotonation in the alkaline solution with adjacent intermediate species of the water photo-oxidation reaction, thereby involving two reaction sites as in Langmuir–Hinshelwood reactions. The devised kinetic model reproduces our main observations and predicts coexistence of two surface reaction paths (bi-stability) in a certain range of potentials and H2O2 concentrations. This prediction is confirmed experimentally by observing a hysteresis loop in the photocurrent voltammogram measured in the predicted coexistence range.

本文言語英語
論文番号4060
ジャーナルNature communications
9
1
DOI
出版ステータス出版済み - 12 1 2018
外部発表はい

All Science Journal Classification (ASJC) codes

  • 化学 (全般)
  • 生化学、遺伝学、分子生物学(全般)
  • 物理学および天文学(全般)

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