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Formation of hydroperoxo (-OOH) species on the surface of self-doped BiWO: reactivity towards As() oxidation
Ist Teil von
Physical chemistry chemical physics : PCCP, 2020-06, Vol.22 (22), p.12456-12464
Erscheinungsjahr
2020
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
Bi
2+
x
WO
6
is a cost-effective and environmentally friendly photocatalyst that shows high reactivity in the oxidation of various contaminants under visible light. However, under alkaline conditions, the reactive oxidative species in the Bi
2+
x
WO
6
system are still not clear yet. In this study, it is observed that the oxidation rates of As(
iii
) increase with increasing pH values in the Bi
2.15
WO
6
system. Photoluminescence and the Mott-Schottky analyses confirm that OH
−
promotes the separation and transfer of photogenerated electron-hole pairs over Bi
2.15
WO
6
, thus facilitating the oxidation of As(
iii
). Electron spin resonance spectra analysis and quenching experiments rule out contributions of *OH, O
2
&z.rad;
−
,
1
O
2
and superoxo species to As(
iii
) oxidation and indicate that surface -OOH and/or H
2
O
2
are indeed the predominant species under alkaline conditions. The improved production of H
2
O
2
by H-donors such as glucose and phenol, as well as the UV-vis diffuse reflectance and Raman analyses, further confirms the formation of surface -OOH on Bi
2.15
WO
6
under alkaline conditions. In the dark, the significant higher oxidation rate of As(
iii
) by H
2
O
2
-Bi
2.15
WO
6
than that by H
2
O
2
alone reveals that surface −OOH, instead of H
2
O
2
, plays an important role in As(
iii
) oxidation. This study enriches our understanding of the diversity of reactive oxygen species (ROS) in the Bi
2.15
WO
6
system and gives new insight into the mechanism involved in the oxidation of As(
iii
) under alkaline conditions.
The formation of -OOH groups and their high reactivity for As(
iii
) oxidation under visible light and alkaline conditions are demonstrated.
Sprache
Englisch
Identifikatoren
ISSN: 1463-9076
eISSN: 1463-9084
DOI: 10.1039/d0cp00569j
Titel-ID: cdi_rsc_primary_d0cp00569j
Format
–
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