Polyoxometalate Immobilized on Graphene via Click Reaction for Simultaneous Dismutation of H₂O₂ and Oxidation of Sulfur Mustard Simulant

Abstract

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 K 1.5 Cs 5.5 [γ-SiW 10 O 39 Cu 2 (N 3 ) 2 ] (SiW 10 Cu 2 (N 3 ) 2 ) and the alkynyl groups on functionalized graphene. This novel strategy allowed for controllable formation of interfacial catalysts (SiW 10 Cu 2 /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 SiW 10 Cu 2 /GO catalyst exhibited excellent stability and highly efficient reactivity or selectivity for dismutation of H 2 O 2 and oxidation of 2-chloroethyl ethyl sulfide (CEES). SiW 10 Cu 2 /GO was active for evolving oxygen from H 2 O 2 dismutation at a rate of 1.35 × 10 −1 μmol s −1 , which was much higher than that by using its parent SiW 10 Cu 2 (N 3 ) 2 (1.89 × 10 −2 μmol s −1 ) and similar to that of the reported [Ru 4 (μ-OH) 2 (μ-O) 4 (H 2 O) 4 ][γ-SiW 10 O 36 ] 2 10− (1.24 × 10 −1 μmol s −1 ) catalyst. Therefore, this activity permitted it to mimic catalase (H 2 O 2 → H 2 O + O 2 ) as an inorganic synzyme at 27 °C. The simultaneous generation of O 2 and highly selective detoxification of CEES to nontoxic sulfoxide CEESO demonstrated the potential for personnel protection against chemical warfare agents. Moreover, SiW 10 Cu 2 / GO exhibited higher activity for the oxidation of CEES to sulfide CEESO with higher selectivity in the presence of O 2 . 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.

Efficient Catalytic Oxidative Desulfurization toward Thioether and Sulfur Mustard Stimulant by Polyoxomolybdate–Resorcin[4]arene-Based Metal–Organic Materials

“…Remarkably, the catalytic oxidation activity of 1 toward CEES is comparable to those of the reported POM-based metal–organic catalysts. − For example, the conversion of CEES catalyzed by 1 is up to 99% with a CEESO selectivity of 97% at 40 °C within 25 min (entry 2, Table ). For the known PW 12 @NU-1000 catalyst, a similar conversion (98%) of CEES was achieved under the similar conditions, but the selectivity of CEESO is only up to 57% .…”

Dual-purpose high-efficiency air filter paper loaded with reactive zirconium hydroxide for the filtration aerosols and degradation of chemical warfare agents

“…The pressure drop without AFP in the xture is 137.2 Pa. The permeability coefficient (K f , %) was calculated using formula (4) and the ltration efficiency (h, %) was calculated using formula (5). The pressure drop of the AFP was measured using an inclined micromanometer.…”

“…3,4 It not only poses a threat to personnel and equipment, but also makes it more difficult to dispose of scrap. In recent years, the integrated technology for protection and decontamination has continued to develop, and a number of protective materials, such as carbon 5 and polymer materials, [6][7][8] with self-decontamination function have been exploited one aer another. For example, John Walker et al 9 added organic phosphate dehydratase OPAA and modied dehydratase OPAA-C18 coated with high-branched polyvinyloxazoline into the spinning dope and adopted a highvoltage electrostatic ber-forming process to obtain a selfdetoxifying membrane, which can effectively promote the hydrolysis of the chemical warfare agents (CWAs) simulant diisopropyluorophosphate (DIFP).…”

Catalytic Processes for the Neutralization of Sulfur Mustard

“…[90][91][92][93] It is worth mentioning that the nature of the metal ions in each of the binary catalyst series have little impact on the reaction rates.P OMs immobilized on solid supports have also been studied for the catalysis of CEES oxidation to CEESO by H 2 O 2 .T hese heterogeneous systemsi nclude ar eticulatedg el materiali ncorporating hexavanadate clusters (entry 6), [94] am ixed Zn/Cr hydroxide layer materialw ith intercalated transition metal-substituted polyoxotungstate (entry 7), [95] and aC u-substituted POM [Si-W 10 O 36 Cu 2 (N 3 ) 2 ] 6À that was bondedt ot he surfaceo fg raphene by an alkyne-azidec ycloaddition( entry 8);t his was also studied as ac atalystf or CEES oxidationb yO 2 (see section 3.4.2). [96] Overall,m any POMs efficiently catalyze the oxidation of CEES by H 2 O 2 ,b ut the gain (in catalytic rates) compared with simple monomeric anionic metal oxidesi sr ather limited.…”

“…[61] Wang and co-workers reported that graphene-immobilized [SiW 10 O 36 Cu 2 (N 3 ) 2 ] 6À (section 3.4.1) catalyzed the selective oxidation of CEES to sulfoxide under af low of dioxygen (10 mL min À1 )i n7 5% yield over 6h.T he conversion is approximately six times slower compared with the same process in-volvingH 2 O 2 insteado fO 2 as the oxidant. [96] 4. Photocatalytic Neutralization…”