Photoelectrocatalytic oxidation of As(III) over hematite photoanodes: A sensible indicator of the presence of highly reactive surface sites

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61989592%3A15310%2F18%3A73590228" target="_blank" >RIV/61989592:15310/18:73590228 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0013468618322199" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0013468618322199</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.electacta.2018.10.003" target="_blank" >10.1016/j.electacta.2018.10.003</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Photoelectrocatalytic oxidation of As(III) over hematite photoanodes: A sensible indicator of the presence of highly reactive surface sites

Popis výsledku v původním jazyce

Hematite-based photoanodes were used for the photoelectrocatalysed batch oxidation of As(III) in water at pH 7 and 10. Tests were carried out at different As(III) initial concentrations, ranging from 150 mu g/L to 30 mg/L. With no pre-treatments, an initial inactive period of 40-50 min was always observed at the beginning of every test. This initial inactive period is completely removed by a surface modification of surface active sites induced by a pre-polarisation at 800 mV (vs. Ag/AgCl). The water splitting active sites related to the Fe(III)-Fe(IV) redox couple were proved to be not active towards As(III) oxidation. The modifications induced by the anodic prepolarisation were deeply studied: no evidence of the formation of surface highly oxidised iron sites (Fe(V) or Fe(VI)) and/or of highly reactive oxygen vacant sites emerges from XPS analysis. Rather, all collected characterisation data support the conclusion that more reactive terminal oxygen species are necessary for As(III) oxydation. The As(III) abatement reaction was modelled by two subsequent first order kinetics in As(III), independently from the initial As(III) concentration: this behaviour was explained suggesting that the highly reactive sites, being formed after prepolarisation, are gradually depleted during the reaction. As this reaction was proved to be very sensitive to the presence of highly reactive iron sites, its utilisation as a probe reaction to study hematite photoanodes is suggested.

Název v anglickém jazyce

Photoelectrocatalytic oxidation of As(III) over hematite photoanodes: A sensible indicator of the presence of highly reactive surface sites

Popis výsledku anglicky

Hematite-based photoanodes were used for the photoelectrocatalysed batch oxidation of As(III) in water at pH 7 and 10. Tests were carried out at different As(III) initial concentrations, ranging from 150 mu g/L to 30 mg/L. With no pre-treatments, an initial inactive period of 40-50 min was always observed at the beginning of every test. This initial inactive period is completely removed by a surface modification of surface active sites induced by a pre-polarisation at 800 mV (vs. Ag/AgCl). The water splitting active sites related to the Fe(III)-Fe(IV) redox couple were proved to be not active towards As(III) oxidation. The modifications induced by the anodic prepolarisation were deeply studied: no evidence of the formation of surface highly oxidised iron sites (Fe(V) or Fe(VI)) and/or of highly reactive oxygen vacant sites emerges from XPS analysis. Rather, all collected characterisation data support the conclusion that more reactive terminal oxygen species are necessary for As(III) oxydation. The As(III) abatement reaction was modelled by two subsequent first order kinetics in As(III), independently from the initial As(III) concentration: this behaviour was explained suggesting that the highly reactive sites, being formed after prepolarisation, are gradually depleted during the reaction. As this reaction was proved to be very sensitive to the presence of highly reactive iron sites, its utilisation as a probe reaction to study hematite photoanodes is suggested.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10405 - Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis)

Projekt

<a href="/cs/project/EF15_003%2F0000416" target="_blank" >EF15_003/0000416: Pokročilé hybridní nanostruktury pro aplikaci v obnovitelných zdrojích energie</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

ELECTROCHIMICA ACTA

ISSN

0013-4686

e-ISSN

—

Svazek periodika

292

Číslo periodika v rámci svazku

DEC

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

10

Strana od-do

828-837

Kód UT WoS článku

000449708500088

EID výsledku v databázi Scopus

2-s2.0-85056149197