Decontamination of Chemical Warfare Agents by Zn2+ and Ge4+ co-doped TiO2 nanocrystals at sub-zero temperatures: A solid-state NMR and GC study

Abstract

Using solid-state NMR spectroscopy (SSNMR) and gas chromatography (GC) we studied the sub-zero temperature decontamination performance of Chemical Warfare Agents (sulphur mustard (HD), soman (GD) and S-2-(diisopropylamino)ethyl O-ethyl methylphosphonothiolate (VX)) and their simulants (2-chloroethyl ethyl sulphide (2-CEES) and dimethyl methylphosphonate (DMMP)) on a novel nanoparticulate Zn2+ and Ge4+ co-doped titanium dioxide (Zn-Ge-TiO2) material. To discover further progress toward the practice use of the powdered catalyst and improve its low-temperature disinfection, a novel suspension decontaminant was prepared successively by suspending Zn-Ge-TiO2 in hydrofluoroether (HFE). By means of a variety of characterization methods such as XRD, BET, BJH, SEM and TEM, the evolution of structure and properties across Zn2+ and Ge4+doping were systematically studied. Our data show that Zn (5.28 wt%)-Ge (1.48 wt%)-TiO2 exhibited the best photocatalytic performance. Versus undoped TiO2, the sample has unchanged crystal structure (anatase) and decreased average pore diameter (2.86 nm), accompanied with increased specific surface area (424.9 m2/g), crystallite size (5.8 nm) and pore volume (0.29 cm3/g). Under simulated sunlight irradiation at −30 °C, after a reaction time of 120 min, the degradation efficiency of HD, GD and VX on the suspension composed of Zn (5.28 wt%)-Ge (1.48 wt%)-TiO2 and HFE-458 (HCF2CF2CH2OCF2CF2H) were all over 99.95%. This indicated that the suspension will have a promising prospect of application in CWAs decontamination under the sub-zero environment.