Selective detoxification of a sulfur mustard simulant in air by a methylene blue-functionalized metal–organic framework

Efficient degradation of sulfur mustard is essential owing to its extreme toxicity and widespread use as a chemical warfare agent. However, current degradation methods often lack selectivity and generate highly toxic by-products. Herein, we demonstrate an approach for the selective photodegradation of a sulfur mustard simulant using singlet oxygen (¹O₂) produced by a methylene blue (MB)-modified UiO-66-(COOH)₂ (UC, a classical metal-organic framework) composite, termed as MB@UC. The composite was prepared <i>via</i> adsorption of MB onto the surface of UC through strong electrostatic interactions. The MB@UC composite demonstrates high ¹O₂ generation, enabling selective detoxification of a sulfur mustard simulant (2-chloroethyl ethyl sulfide) into relatively non-toxic sulfoxide, with a half-life of 1.8 minutes under ambient conditions. Compared to traditional detoxifying agents, the MB@UC composite offers superior selectivity, rapid degradation, and excellent recyclability, maintaining its performance over multiple cycles. This work presents a promising strategy for the development of advanced heterogeneous photosensitizers for the detoxification of chemical warfare agents.