Two-site H2O2 photo-oxidation on haematite photoanodes

被引：26

作者：

Avital, Yotam Y. ^{[1
]}

Dotan, Hen ^{[2
]}

Klotz, Dino ^{[2
]}

Grave, Daniel A. ^{[2
]}

Tsyganok, Anton ^{[2
]}

Gupta, Bhavana ^{[1
]}

Kolusheva, Sofia ^{[3
]}

Visoly-Fisher, Iris ^{[1
]}

Rothschild, Avner ^{[2
]}

Yochelis, Arik ^{[1
,4
]}

机构：

[1] Ben Gurion Univ Negev, BIDR, Swiss Inst Dryland Environm & Energy Res, Dept Solar Energy & Environm Phys, IL-8499000 Midreshet Ben Gurion, Israel

[2] Technion Israel Inst Technol, Dept Mat Sci & Engn, IL-32000 Haifa, Israel

[3] Ben Gurion Univ Negev, Ilse Katz Inst Nanoscale Sci & Technol, IL-8410501 Beer Sheva, Israel

[4] Ben Gurion Univ Negev, Dept Phys, IL-8410501 Beer Sheva, Israel

来源：

NATURE COMMUNICATIONS | 2018年 / 9卷

基金：

以色列科学基金会; 欧洲研究理事会;

关键词：

PHOTOELECTROCHEMICAL WATER OXIDATION; CHARGE-CARRIER DYNAMICS; OXYGEN EVOLUTION; IRON-OXIDE; ALPHA-FE2O3; PHOTOANODES; SURFACE-STATES; SOLAR; CATALYST; MECHANISM; INTERFACES;

D O I：

10.1038/s41467-018-06141-0

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

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 (alpha-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.

引用

页数：10

共 69 条

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