Manganese Oxides with Different Morphologies In Situ Anchored onto Ti₃C₂T_x Nanosheets: Highly Effective Decontamination toward Sulfur Mustard Simulants

Abstract

Manganese oxides with porous structure and abundant active sites show potential in degrading sulfur mustard (HD). However, there is an interface effect between the oily liquid HD and nano oxides, and the powder is prone to agglomeration, which leads to incomplete contact and limited degradation ability. Here, we demonstrate a simple hydrothermal method for preparing MnO 2 /Ti 3 C 2 composites to address this problem. The influence of morphology and crystal structure on performance are examined. Herein, flower-like MnO 2 is loaded onto the surface or interlayer of Ti 3 C 2 -MXene nanosheets during in situ formation, significantly expanding the specific surface area. It also provides abundant acid− base sites and oxygen vacancies for the degradation of simulants 2chloro-ethyl-ethyl thioether (2-CEES) without external energy, resulting in a reaction half-life as fast as 12.5 min. The relationship between structure and performance is clearly elaborated through temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and X-ray absorption fine structure (XAFS) analyses. Based on in situ attenuated total reflection−Fourier transform infrared (ATR−FTIR) analysis, gas chromatography−mass spectrometry (GC−MS) analysis, and density functional theory (DFT) calculation, the proposed degradation pathway of the 2-CEES molecule is a synergistic effect of hydrolysis, elimination, and oxidation. Furthermore, the products are nontoxic or low toxic. Metal oxide/MXene composites are first illustrated for their potential use in degrading sulfur mustard, suggesting new insights into these materials as novel decontamination for decomposing chemical warfare agents.