Preparation of a porphyrin-polyoxometalate hybrid and its photocatalytic degradation performance for mustard gas simulant 2-chloroethyl ethyl sulfide

ABSTRACT By combining 5,10,15,20-tetra(4-chlorine)phenylporphyrin (TClPP) and α-Keggin polyoxometalate H5PV2Mo10O40 (H5PVMo) via a simple ion-exchange method, an organic-inorganic hybrid material [C44H28N4Cl4]1.5[H2PMo10V2O40]•2C2H6O (H2TClPP-H2PVMo) was prepared and thoroughly characterized by a variety of techniques. The homogeneous photocatalytic degradation of 2-chloroethyl ethyl sulfide (CEES) (5 μL) by H2TClPP-H2PVMo (1 × 10−6 mol/L) was studied in methanol and methanol-water mixed solvent (v/v = 1:1), in which the degradation rate of CEES reached 99.52% and 99.14%, respectively. The reaction followed first-order reaction kinetics, and the half-life and kinetic constant in methanol and the mixed solvent were respectively 33.0 min, -0.021 min−1 and 15.7 min, -0.043 min−1. Mechanism analysis indicated that under visible light irradiation in the air, CEES was degraded via oxidation and alcoholysis/hydrolysis in methanol and the mixed solvent. O2•− and 1O2 generated by H2TClPP-H2PVMo selectively oxidized CEES into a non-toxic sulfoxide. Singlet oxygen capture experiments showed that H2TClPP-H2PVMo (Φ = 0.73) had a higher quantum yield of singlet oxygen than TClPP (Φ = 0.35) under an air atmosphere and visible light irradiation.