A Versatile Self-Detoxifying Material Based on Immobilized Polyoxoniobate for Decontamination of Chemical Warfare Agent Simulants

A decontaminating composite, Mg₃Al-LDH-Nb₆, has been successfully prepared by immobilizing Lindqvist [H₃Nb₆O₁₉]⁵⁻ (Nb₆) into a Mg₃Al-based layered double hydroxide (Mg₃Al-LDH). To our knowledge, this represents the first successful approach to the immobilization of polyoxoniobate. As a versatile catalyst, Mg₃Al-LDH-Nb₆ can effectively catalyze the degradation of both vesicant and nerve agent simulants by multiple pathways under mild conditions. Specifically, the sulfur mustard simulant, 2-chloroethyl ethyl sulfide (CEES), is converted into the corresponding nontoxic 2-chloroethyl ethyl sulfoxide (CEESO) by selective oxidation, whereas the Tabun (G-type nerve agent) simulant, diethyl cyanophosphonate (DECP), and the VX (V-type nerve agent) simulant, O,S-diethyl methylphosphonothioate (OSDEMP), are detoxified through hydrolysis and perhydrolysis, respectively. A possible mechanism is proposed on the basis of control experiments and spectroscopic studies. The Mg₃Al-LDH-Nb₆ composite exhibits remarkable robustness and can be readily reused for up to ten cycles with negligible loss of its catalytic activity. More importantly, a protective “self-detoxifying” material has easily been constructed by integrating Mg₃Al-LDH-Nb₆ into textiles. In this way, the flexible and permeable properties of textiles have been combined with the catalytic activity of polyoxoniobate to remove 94 % of CEES in 1 h by using nearly stoichiometric dilute H₂O₂ (3 %) as oxidant with 96 % selectivity.