In this section
@article{Heiba:2024:10.1021/acsami.4c14247,
author = {Heiba, HF and Bullen, JC and Kafizas, A and Petit, C and Jiang, D and Weiss, DJ},
doi = {10.1021/acsami.4c14247},
journal = {ACS Appl Mater Interfaces},
title = {Role of the Sn-TiO2/Ti-SnO2 Heterojunction in Enhancing the Photocatalytic Oxidation of Arsenite (AsIII) through the Promotion of Charge Carrier Lifetime.},
url = {http://dx.doi.org/10.1021/acsami.4c14247},
year = {2024}
}
TY - JOUR
AB - This study proposes the heterojunction photocatalyst, Sn-doped TiO2/Ti-doped SnO2 (herein named Sn1Ti1O2), as a promising alternative to pure TiO2. Sn1Ti1O2 demonstrates improved light harvesting efficiency over TiO2 by generating longer-lived electron-hole (eCB--hVB+) pairs, while also displaying a smaller band gap compared to pure TiO2. Consequently, we show that it is a promising candidate for the photocatalytic oxidation (PCO) of AsIII to the less toxic and more readily removable form AsV. Transient absorption spectroscopy (TAS) shows increased eCB--hVB+ recombination half-lives from ∼0.5 ms in TiO2 to ∼1 ms in Sn1Ti1O2. The initial transient absorption signal for Sn1Ti1O2 is twice that of pure TiO2, suggesting early time scale (pre-μs) suppression of (eCB--hVB+) recombination. Moreover, TAS showed that Sn1Ti1O2 possesses more reactive charge carriers than TiO2 under reactions with chemical scavengers. For the first time, TAS experiments were conducted using both a colorimetric indicator (molybdate) and AsIII to determine the PCO kinetics from AsIII to AsV. The TAS molybdateAsIII experiment results indicate that the oxidation process occurs on the sub-microsecond time scale, with a notable increase in absorption at ∼700 nm, providing evidence of the formation of the AsVmolybdate blue complex. PCO experiments showed that •OH radicals played the predominant role during PCO, followed by superoxide radicals (O2•). •OH scavengers including isopropanol, rebamipide anhydrous, and dimethyl sulfoxide (DMSO) reduce the PCO yield of AsIII to 21, 30, and 23%, respectively. While O2• scavengers including superoxide dismutase (SOD) and p-benzoquinone suppressed the PCO yield of AsIII to a lesser degree, with yields of 35 and 49% seen, respectively. The effects of irradiance intensity, salinity, pH, AsIII concentration, and photocatalyst mass on both the quantum efficiency (QE) and PCO kinetics were investigated. The Sn1Ti1O2 catalyst exh
AU - Heiba,HF
AU - Bullen,JC
AU - Kafizas,A
AU - Petit,C
AU - Jiang,D
AU - Weiss,DJ
DO - 10.1021/acsami.4c14247
PY - 2024///
TI - Role of the Sn-TiO2/Ti-SnO2 Heterojunction in Enhancing the Photocatalytic Oxidation of Arsenite (AsIII) through the Promotion of Charge Carrier Lifetime.
T2 - ACS Appl Mater Interfaces
UR - http://dx.doi.org/10.1021/acsami.4c14247
UR - https://www.ncbi.nlm.nih.gov/pubmed/39629826
ER -
Dr. Andreas Kafizas
Leader - Solar Coatings Group
e-mail: a.kafizas@imperial.ac.uk
tel: +44(0)20 7594 6752
twitter: @CoatingsSolar