Detoxification of mustard gas surrogate on ZnO2/g-C3N4 composites: Effect of surface features' synergy and day-night photocatalysis

Porous zinc peroxide/graphitic carbon nitride nanocomposites were synthesized and characterized by XRD, N-2 adsorption, SEM, DRUV-Vis spectroscopy, and thermal analysis. The affinity of the samples to reactively adsorb and decompose vapors of chemical warfare agent surrogate of mustard gas, 2-chloroethyl ethyl sulfide (CEES), was evaluated. The synergy of the composite formation resulted in the development of a porosity and in a marked improvement in the activity to detoxify CEES, as compared to the composite components. The CEES degradation efficiencies under visible light and in the dark wre similar, with a conversion over 90 %. This was linked to day-light catalysis where graphitic carbon nitride worked as a photoactive phase and ZnO2- as energy storage component. In the dark, stored electrons participated in radicals-involved reactions. The porosity was found as an important factor since it enhanced the adsorption energy of CEES and the efficiency of electron transfer processes.