Zinc peroxide nanoparticles: Surface, chemical and optical properties and the effect of thermal treatment on the detoxification of mustard gas

Highly porous zinc peroxide nanoparticles were synthesized at ambient conditions following a one-pot wet precipitation method. Subsamples were calcined at various temperatures up to 400 °C. The structural, morphological, optical and chemical features were evaluated by X-Ray diffraction, N2 adsorption, scanning electron microscopy, diffuse reflectance UV–vis spectroscopy, Raman spectroscopy, and thermal analysis. The degree of ZnO2 decomposition to ZnO was monitored by XRD or Raman spectroscopy. The content of peroxide and the ability to form hydroxyl and super oxide radicals were also evaluated. The affinity of the synthesized samples to reactively adsorb chemical warfare agent surrogate of mustard gas, 2-chloroethyl ethyl sulfide (CEES) or ethyl ethyl sulfide (EES) was evaluated. Zinc peroxide nanoparticles were found as the best performing material, due to a high porosity and favorable surface chemistry. Moreover, they showed the ability to selectively oxidize EES to ethyl ethyl sulfoxide. In the case of CEES adsorption and subsequent reaction, the major surface reaction product was hydroxyethyl ethylsulfide (HEES). This suggests that the formation of a transient intermediate sulfonium cation is the predominant detoxification pathway. Weakly adsorbed and/or structural water enhanced the vapor retention and the decomposition performance. The ultimate task was to evaluate the detoxification performance against the real mustard gas. Zinc peroxide nanoparticles showed a marked detoxification activity with a conversion rate of 67.5%.