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Cobalt-containing catalysts supported on ZSM-5 zeolite and mesoporous siliceous SBA-15 were prepared and characterized by nitrogen sorption, X-ray diffraction, scanning electron and transmission electron microscopies, energydispersive X-ray, Fourier transform infrared, ultraviolet−visible diffuse reflectance, X-ray photoelectron spectroscopies, and temperature-programmed desorption of ammonia measurement. The effect of cobalt loading ratio on the selective catalytic reduction (SCR) of nitrogen oxides (NO x ) with ammonia was investigated. The existing Brønsted acid sites contributed to the cobalt species finely dispersed within the ZSM-5 zeolite, either as isolated cobalt ions anchored at α, β, and γ sites, or as amorphous cobalt oxides enriched on the ZSM-5 surface. NO x conversion profiles of Co/ZSM-5 exhibited two peaks. The low-temperature peak (<300 °C) was induced by cobalt ions at β and γ sites, while the high-temperature peak (>300 °C) was assigned to the amorphous and crystalline cobalt oxides. With increasing cobalt content, the intensity of lowtemperature peak was enhanced monotonously, and the peak position remained constant. Increasing cobalt content promoted the high-temperature peak to shift toward lower temperatures. NO x conversion profiles of Co/SBA-15 only exhibited a hightemperature peak. For Co/SBA-15, the poor dispersion of cobalt species was derived from the absence of Brønsted acid sites. The activity of Co/SBA-15 catalysts was lower than that of the Co/ZSM-5 catalysts due to inactive cobalt ions anchored on isolated Si−OH groups, and agglomerated cobalt oxides within the SBA-15 channels blocking the reactant pathway to active sites.

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Al-PTFE (Al-polytetrafluoroethene) is an important kind of Reactive Material (RM), however only limited importance was placed to the effect of crystallinity of PTFE on the mechanical and reactive behavior. This paper investigated the influence of crystallinity on the compression behavior of Al-PTFE at strain rates range from 10 −2 to 3 × 10 3 s −1 . Two kinds of samples were prepared by different sintering procedures to acquire different crystallinity. The samples' crystallinity was characterized by the density method and X-ray diffraction method. The samples were tested using an electro-hydraulic press for quasi-static loading, and split Hopkinson pressure bars (SHPBs) for high strain rates. Low crystalline samples have consistently higher strength and toughness than the high crystalline samples. The phenomenon was explained by an "elastic-plastic network" model combined with the effect of chain entanglement density. A bilinear dependence of true stress on logε was observed, and Johnson-Cook models were fitted separately according to the different strain rate sensitivity. Finally, a close connection between fracture and initiation of Al-PTFE was confirmed in quasi-static tests, SHPB tests, and drop weight tests. It was hypothesized that the high temperature at the crack tips of PTFE is an important promoting factor of initiation.