Carbon textile swatch was oxidized and impregnated with copper hydroxynitrate. A subsample was then further heated at 280 °C to form copper oxide. The swatches preserved their integrity through the treatments. As final products, they exhibited remarkable detoxification properties for the nerve agent surrogate dimethyl chlorophosphate (DMCP). Based on the amount of reactive copper phases deposited on the fibers, their adsorption capacities were higher than those of the bulk powders. After 1 day exposure to DMCP (1:1 weight ratio adsorbent/DMCP), 99% of the initial amount of DMCP was eliminated. A synergistic effect of the composite components was clearly seen. GC-MS results showed that the main surface reaction product was chloromethane. Its formation indicated hydrolysis as a detoxification path. Surface analyses showed phosphate bonding to the fibers and formation of copper chloride. The appearance of the latter species results in a clear textile color change, which suggests the application of these fabrics not only as catalytic protection agents but also as sensors of nerve agents.
Porous carbons containing either B and N heteroatom (∼10 at.% each) or B‐ and N‐free were synthesized and used as ORR metal‐free catalysts. The number of electron transfer was close to 4 (3.94) regardless the presence or not of heteroatom‐based catalytic centers, and the onset potential reached 0.827 V (on Pt/C 0.888 V). The carbons were extensively characterized from the viewpoints of their surface chemistry and porosity. The results indicated that a high volume of small pores where oxygen can be strongly adsorbed enhances the ORR efficiency, positively affecting the number of electron transfer and the value of the onset potential. On carbons with moderate volume of ultramicropores, N and B catalytic centers compensate the porosity effect enhancing the performance. These two mechanisms of ORR can coexist leading to a very efficient process on metal free carbon‐based porous catalysts.
Composites of magnetite and two-line ferrihydrite with graphite oxide (GO) were synthesized and tested as hydrogen sulfide adsorbents. Exhausted and initial composites were characterized by the adsorption of nitrogen, X-ray diffraction, potentiometric titration, thermal analysis, and FTIR. The addition of GO increased the surface area of the composites due to the formation of new micropores. The extent of the increase depended on the nature of the iron (hydr)oxide and the content of GO. The addition of GO did not considerably change the crystal structure but increased the number of acidic functional groups. While for the magnetite composites an increase in the H2S adsorption capacity after GO addition was found, the opposite effect was recorded for the ferrihydrite composites. That increase in the adsorption capacity was linked to the affinity of the composites to adsorb water in mesopores of specific sizes in which the reaction with basic surface groups takes place. Elemental sulfur and ferric and ferrous sulfates were detected on the surface of the exhausted samples. A redox reactive adsorption mechanism is proposed to govern the retention of hydrogen sulfide on the surface of the composites. The incorporation of GO enhances the chemical retention of H2S due to the incorporation of OH reactive groups and an increase in surface heterogeneity.
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