Enhancing the quantum yield of singlet oxygen: photocatalytic degradation of mustard gas simulant 2-chloroethyl ethyl sulfide catalyzed by a hybrid of polyhydroxyl aluminum cations and porphyrin anions.
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ABSTRACT: By combining the anionic salt meso-tetra(4-carboxyphenyl)porphyrin (TCPP4-) and the Keggin polyoxometalate cation cluster [Al13O4(OH)24(H2O)12]7+ via a simple ion-exchange method, a hybrid (C48H26N4O8)[Al13O4(OH)24(H2O)12]2(OH)10·18H2O (Al13-TCPP) was prepared and thoroughly characterized as a prototype of polyoxometalate-porphyrin hybrids for the photocatalytic degradation of the mustard gas simulant 2-chloroethyl ethyl sulfide (CEES). The experimental results showed that the catalytic degradation rate of CEES in the presence of Al13-TCPP reached 96.16 and 99.01% in 180 and 90 min in methanol and methanol-water solvent mixture (v/v = 1 : 1), respectively. The reaction followed first-order reaction kinetics, and the half-life and kinetic constant in methanol and solvent mixture were 39.8 min, -0.017 min-1 and 14.7 min, -0.047 min-1. Mechanism analysis indicated that under visible light irradiation in air, CEES was degraded through a combination of oxidation and alcoholysis/hydrolysis in methanol and the methanol-water solvent mixture. The superoxide radical (O2˙-) and singlet molecular oxygen (1O2) generated by Al13-TCPP selectively oxidized CEES into a non-toxic sulfoxide. The singlet oxygen capture experiments showed that Al13-TCPP (Φ = 0.236) had a higher quantum yield of singlet oxygen generation than H4TCPP (Φ = 0.135) under visible light irradiation in air. The material Al13-TCPP has good reusability, and the degradation rate of CEES can still reach 98.37% after being recycled five times.
SUBMITTER: Yang Y
PROVIDER: S-EPMC9277536 | biostudies-literature | 2022 Jul
REPOSITORIES: biostudies-literature
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