As a momentous energetic group, a nitro group widely exists in high-energy-density materials (HEDMs), such as trinitrotoluene (TNT), 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX), etc. The nitro group has a significant effect on improving the oxygen balance and detonation performances of energetic materials (EMs). Moreover, the nitro group is a strong electron-withdrawing group, and it can increase the acidity of the acidic hydrogen-containing nitrogen-rich energetic compounds to facilitate the construction of energetic ionic salts. Thus, it is possible to design nitro-nitrogen-rich energetic compounds with adjustable properties. In this paper, the nitration methods of azoles, including imidazole, pyrazole, triazole, tetrazole, and oxadiazole, as well as azines, including pyrazine, pyridazine, triazine, and tetrazine, have been concluded. Furthermore, the prospect of the future development of nitrogen-rich heterocyclic energetic compounds has been stated, so as to provide references for researchers who are engaged in the synthesis of EMs.

The crystal structure has a great influence on mechanical sensitivity and detonation performance of energetic materials. An efficient microfluidic platform was applied for size, morphology, and crystallinity controllable preparation of ultrafine HMX. The microfluidic platform has good mixing performance, quick response, and less reagent consumption. The ultrafine γ-HMX was first prepared at room temperature by microfluidic strategy, and the crystal type can be controlled accurately by adjusting the process parameters. With the increase in flow ratio, the particle size decreases gradually, and the crystal type changed from β-HMX to γ-HMX. Thermal behavior of ultrafine HMX shows that γ→δ is easier than β→δ, and the phase stability of HMX is β > γ > δ. Furthermore, the ultrafine β-HMX has higher thermal stability and energy release efficiency than that of raw HMX. The ultrafine HMX prepared by microfluidic not only has uniform morphology and narrow particle size distribution, but also exhibits high density and low sensitivity. This study provides a safe, facile, and efficient way of controlling particle size, morphology, and crystallinity of ultrafine HMX.

Lithium-oxygen (Li-O₂) batteries have a great potential in energy storage and conversion due to their ultra-high theoretical specific energy, but their applications are hindered by sluggish redox reaction kinetics in the charge/discharge processes. Redox mediators (RMs), as soluble catalysts, are widely used to facilitate the electrochemical processes in the Li-O₂ batteries. A drawback of RMs is the shuttle effect due to their solubility and mobility, which leads to the corrosion of a Li metal anode and the degradation of the electrochemical performance of the batteries. Herein, we synthesize a polymer-based composite protective separator containing molecular sieves. The nanopores with a diameter of 4 Å in the zeolite powder (4A zeolite) are able to physically block the migration of 2,2,6,6-tetramethylpiperidinyloxy (TEMPO) molecules with a larger size; therefore, the shuttle effect of TEMPO is restrained. With the assistance of the zeolite molecular sieves, the cycle life of the Li-O₂ batteries is significantly extended from ∼ 20 to 170 cycles at a current density of 250 mA·g⁻¹ and a limited capacity of 500 mAh·g⁻¹. Our work provides a highly effective approach to suppress the shuttle effects of RMs and boost the electrochemical performance of Li-O₂ batteries.

Photocatalysts with a superior activity range, from ultraviolet (UV) to near-infrared (NIR) light, are attractive for solar utilization. From this perspective, sulfides are promising due to their narrower bandgap than oxides. In this report, NaBiS₂ was synthesized hydrothermally under mild conditions by adjusting the alkaline amount. The rough NaBiS₂ nanosheets possessed various surface atomic configurations on their surfaces, including amorphous clusters and amorphous nano-domains, revealed by HRTEM. A theoretical investigation of the band structure employing the density functional theory (DFT) method for the first time indicated that NaBiS₂ is an indirect bandgap semiconductor with a narrow bandgap of 1.02 eV. Experimentally, it showed excellent photocatalytic activity for the degradation of methyl blue under UV, visible light and NIR light due to its experimental bandgap width of 1.32 eV. A degradation rate of 99.6% was reached after 80 min under full spectrum irradiation.

As the critical first step in structural health management and fault diagnosis, corrosion monitoring is inherently multidisciplinary in nature. While conventional in situ techniques capture real-time electrical, vibrational, and thermal signatures, their effectiveness is constrained by limited detection precision, inefficient data analysis, and unreliable predictive modeling. The convergence of artificial intelligence (AI) and big data analytics has fundamentally transformed this field, generating considerable academic interest over the past decade. Machine learning (ML) – serving as the cornerstone of this revolution – excels not only in extracting nonlinear features from nonstationary processes but also employs probabilistic inference frameworks to quantify predictive uncertainty, thereby substantially augmenting in situ monitoring capabilities. This review systematically examines advancements in ML-assisted corrosion monitoring throughout the preceding decade, categorizing prevalent algorithms according to domain-specific implementations while evaluating enhanced in situ techniques through empirical case studies demonstrating superior data processing efficacy. Finally, we project future trajectories for intelligent monitoring technology in light of persistent challenges and emergent innovations.

The toxic transformation products of hydrazines are of great concern. These products’ properties combined with their formation mechanisms are needed to assess their potential environmental and human impacts. In this study, the gas-phase reaction of hydrazine (N₂H₄), monomethyldrazine (MMH) and unsymmetrical dimethyhydrazine (UDMH) with O₃ have been studied at varying reactant ratios, both in the presence and absence of a radical trap. Gas chromatography-mass spectroscopy (GC-MS) has been implied to follow reactant consumption and product formation. Apart from the reported products detected by Fourier transform infrared spectroscopy (FT-IR), the newly found compounds (hydrazones, formamides, dimethylamine, 1,1,4,4-tetramethyl-1,2-tetrazene,dimethylamino-acetonitrile, N₂, H₂O, et al.) are identified by GC-MS. The relative yields of the organic products vary considerably at different O₃/MMH or UDMH ratios. UDMH and MMH are confirmed as high potential precursors of N-nitrosodimethylamine (NDMA). The presence of hydroxyl radicals (HO·) hinders NDMA formation in MMH-O₃ system. Meanwhile, it increases NDMA formation in UDMH-O₃ system. The suggested reaction mechanisms which account for the observed products are discussed.