Powerful oxidizer N₂O was incorporated into an organic lattice cavity through aeration crystallization, and smart host–guest energetic materials with highly-energetic and low-sensitivity performance were obtained.

Small-angle X-ray scattering (SAXS) is an effective method to obtain microstructural information of materials. However, due to the influence of crystal surface effects, SAXS has a deviation in the characterization of the crystal microstructure. In order to solve the influence of crystal surface effect on the internal defect signal, the microstructure of Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) crystal was characterized by soaking the sample in the matching solution. We found that the absolute scattering intensity, specific surface and volume fraction of the sample in the matching solution are significantly lower than the initial sample, which solves the influence of the crystal surface effect on the test results. Comparing the scattering results of the samples in different electron density matching solutions, it was found that the best result was obtained when using GPL-107 perfluoropolyether (PFPE) matching solution and the same law was obtained by controlling the experiment with 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20) crystal. The fitting density was calculated according to the theoretical density and void volume fraction of the sample, and the calculated results are close to the test results of Particle Density Distribution Analyzer (PDDA). Based on this paper, we provide a method to obtain the correct information of crystal microstructure.

In this paper, the PdO_x nanoparticles modified SnO₂ are prepared using sputtering and wet chemical methods. The SnO₂ nanoparticles are separately added to a concentration of 0.75% to 10% PdCl₂ to obtain a PdCl₂/SnO₂ composite material, which is calcined for 1 to 2 h at the temperatures of 120 °C, 250 °C, 450 °C and 600 °C. The PdO_x/SnO₂ nanocomposite was characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD) and transmission electron microscopy (TEM). Microstructural observations revealed PdO_x with different chemical states attached to the surface of SnO₂. Hydrogen response change tests were performed on the obtained PdO_x/SnO₂ gas sensing materials. The results show that the high gas sensing performance may be attributed to the contribution of the PdO_x-loaded SnO₂. In hydrogen, the best sensitivity response was attained at 80 °C, which is 60 times that of pristine SnO₂. It clarifies the role of PdO_x in the gas sensing mechanisms.