Sanping Zhao,Hailing Xi,Yanjun Zuo,Qi Wang,Zhicheng Wang,Zengyuan Yan
13 C NMR spectra showed that peroxymonocarbonate (HCO 4 − ) was generated in the NaHCO 3 -activated H 2 O 2 solution and pH was a key factor in its production. A cycle for the bicarbonate anion was proposed as HCO 3 − → HCO 3 → (CO 2 ) 2 * → CO 2 (aq) → HCO 4 − (H 2 CO 4 ) → HCO 3 − ( HCO 3 ) basing on the results of NMR, electron paramagnetic resonance, chemiluminescence analysis. In this cycle, (CO 2 ) 2 * was the key intermediate and (CO 2 ) 2 * → 2CO 2 + hv was the rate controlling step. Thioanisole and paraoxon, the simulants of sulfur mustard gas and nerve gas, respectively, were efficiently decontaminated by the NaHCO 3 -activated H 2 O 2 solution. While HCO 4 − was the primary oxidant for the oxidation of thioanisole, O 2 − generated during the decomposition of HCO 4 − or H 2 O 2 led to the secondary oxidation of the sulfide. Paraoxon was degraded in the NaHCO 3 -activated H 2 O 2 solution via nucleophilic substitution by OOH − and OH − , and the degradation rate increased exponentially with increasing pH. Alkali metal ions had a catalytic effect on the degradation of paraoxon. Mustard gas and soman degraded efficiently into nontoxic products in NaHCO 3 -activated H 2 O 2 . A pH range of 9–10 was found to be optimum for the broad-spectrum decontamination of chemical warfare agents and other eco-toxicants using NaHCO 3 -activated H 2 O 2 .
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 MnO2/Ti3C2 composites to address this problem. The influence of morphology and crystal structure on performance are examined. Herein, flower-like MnO2 is loaded onto the surface or interlayer of Ti3C2-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 2-chloro-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.
Xueyan Zhang,Yiming Li,Yue Li,Shengtian Wang,Xiaohong Wang
“Click reactions” are widely used for the synthesis and modification of new materials due to their fascinating advantages (e.g., highly efficient and selective, mild reaction conditions, and lack of side reactions). Redox-active metal-substituted polyoxotungstates (MSPs) were covalently immobilized on a graphene surface by using a “click” reaction between the azido group of K1.5Cs5.5[γ-SiW10O39Cu2(N3)2] (SiW10Cu2(N3)2) and the alkynyl groups on functionalized graphene. This novel strategy allowed for controllable formation of interfacial catalysts (SiW10Cu2/GO) with a single MSP molecule being loaded on the surface of graphene. This interfacing between a single polyoxometalate (POM) molecule and graphene results in several advantages combined with redox properties and higher thermal stability due to the POMs, electronic band structure of graphene, special hydrophobic environment, and single molecular dispersing sites. This SiW10Cu2/GO catalyst exhibited excellent stability and highly efficient reactivity or selectivity for dismutation of H2O2 and oxidation of 2-chloroethyl ethyl sulfide (CEES). SiW10Cu2/GO was active for evolving oxygen from H2O2 dismutation at a rate of 1.35 × 10–1 μmol s–1, which was much higher than that by using its parent SiW10Cu2(N3)2 (1.89 × 10–2 μmol s–1) and similar to that of the reported [Ru4(μ-OH)2(μ-O)4(H2O)4][γ-SiW10O36]210– (1.24 × 10–1 μmol s–1) catalyst. Therefore, this activity permitted it to mimic catalase (H2O2 → H2O + O2) as an inorganic synzyme at 27 °C. The simultaneous generation of O2 and highly selective detoxification of CEES to nontoxic sulfoxide CEESO demonstrated the potential for personnel protection against chemical warfare agents. Moreover, SiW10Cu2/GO exhibited higher activity for the oxidation of CEES to sulfide CEESO with higher selectivity in the presence of O2. Furthermore, recycling and leaching experiments indicated that no significant leaching of POMs was observed from graphene. In addition, the produced CEESO did not aggregate on the catalyst hybrids.
危险品化学品经营许可证（带存储）