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Cesium heteropolysalts Cs 3 PMo 12 O 40 and HCs 3 PVMo 11 O 40 were synthesized by modifying the preparation conditions in order to get materials with a much higher surface area than the original Keggin-type heteropolyacids (H 3 PMo 12 O 40 and H 4 PVMo 11 O 40 ). These solids were used as carriers for the dispersion of H 4 PVMo 11 O 40 heteropolyacid by the incipient wetness impregnation technique. The textural and structural properties of supports and catalysts were examined by scanning electron microscopy, N 2 adsorption-desorption isotherms and Raman spectroscopy. The supported catalysts were studied before and after red/ox pretreatments by X-ray photoelectron spectroscopy, which showed that both the surface composition and oxidized to reduced species ratio depend on the used carrier. The catalytic performances of these novel supported catalysts in the selective oxidation of isobutane to methacrylic acid and methacrolein were studied. The best catalytic properties were obtained when H 4 PVMo 11 O 40 was supported on HCs 3 PVMo 11 O 40 . The isobutane conversion and yield of the desired oxygenates increased along the unsupported H 4 PVMo 11 O 40 < H 4 PVMo 11 O 40 /Cs 3 PMo 12 O 40 < H 4 PVMo 11 O 40 /HCs 3 PVMo 11 O 40 series. cesium heteropolysalts supports, supported H 4 PVMo 11 O 40 , red/ox XPS, isobutane selective oxidation, Keggin-type heteropolycompounds

In the niche area of energetic materials, a balance between energy and safety is extremely important. To address this “energy–safety contradiction”, energetic cocrystals have been introduced. The investigation of the synthesis methods, characteristics, and efficacy of energetic cocrystals is of the utmost importance for optimizing their design and development. This review covers (i) various synthesis methods for energetic cocrystals; (ii) discusses their characteristics such as structural properties, detonation performance, sensitivity analysis, thermal properties, and morphology mapping, along with other properties such as oxygen balance, solubility, and fluorescence; and (iii) performance with respect to energy contents (detonation velocity and pressure) and sensitivity. This is followed by concluding remarks together with future perspectives.

With ultrashort duration and ultrahigh energy, femtosecond laser (fs-laser) pulses are very promising for the precision machining of energetic materials. Compared with the mechanical machining methods of energetic materials, fs-laser machining technology has the advantages of high safety, high precision, and absence of pollution. A deep understanding of the mechanisms between fs-lasers and energetic materials is the basis for the development of fs-laser machining technology. In this paper, the method of reactive molecular dynamics (ReaxFF-MD) was adopted to calculate the fs-laser ablation process of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX, a high explosive compound), and the ablation mechanisms of HMX under different fs-laser energies were studied. The results show that the fs-laser ablation mechanisms of HMX are related to the laser power density. When the laser power density is high enough (3.4 × 10 14 W/cm 2 , 1.0 mJ/pulse), HMX undergoes ionization or decomposition reactions at the picosecond level (∼7.65 ps) and produces a high temperature and pressure plasma. Many N, H, and O single atoms and their ionic products occur along with some small molecular fragments of NO 2 , H 2 O, CO 2 , N 2 , H 2 , NH, NH 2 , CO, OH, CNO 2 and very few toxic products of NO and HNO 2 . In this case, the removal process of HMX occurs via a phase explosion mechanism. As the laser energy decreases, the ionization degree of ablation products decreases, in which the number of monatomic and ionic products decreases, while the number of toxic small molecules (such as NO, HNO 2 , and HNO) increases. When the laser power density is relatively low (0.34 × 10 14 W/cm 2 , 0.1 mJ/pulse), the removal process of HMX occurs via a photomechanical mechanism, and the compound escapes as intact initial HMX molecules. When the laser power density is close to the ablation threshold of the explosive, the HMX molecules only undergo a melting state to some extent without escaping from the surface of the crystal. Therefore, the fs-laser can be used in the precise machining of explosives and preparation of highpurity energetic nanomaterials by a reasonable selection of fs-laser energy.