Bis[3-(5-nitroimino-1,2,4-triazolate)]-based energetic salts were synthesized in a simple, straightforward manner. They exhibit low solubility in available solvents, high hydrolytic stability, excellent thermal stability, high density, positive heat of formation, low shock sensitivity, and excellent detonation properties. The physical and energetic properties of some salts are similar and even superior to those of RDX.

Co 3 O 4 spinel has been widely investigated as a promising catalyst for the oxidation of volatile organic compounds (VOCs). However, the roles of tetrahedrally coordinated Co 2+ sites (Co 2+ T d ) and octahedrally coordinated Co 3+ sites (Co 3+ O h ) still remain elusive, because their oxidation states are strongly influenced by the local geometric and electronic structures of the cobalt ion. In this work, we separately studied the geometrical-site-dependent catalytic activity of Co 2+ and Co 3+ in VOC oxidation on the basis of a metal ion substitution strategy, by substituting Co 2+ and Co 3+ with inactive or low-active Zn 2+ (d 0 ), Al 3+ (d 0 ), and Fe 3+ (d 5 ), respectively. Raman spectroscopy, X-ray absorption fine structure (XAFS), and in situ DRIFTS spectra were thoroughly applied to elucidate the active sites of a Co-based spinel catalyst. The results demonstrate that octahedrally coordinated Co 2+ sites (Co 2+ O h ) are more easily oxidized to Co 3+ species in comparison to Co 2+ T d , and Co 3+ are responsible for the oxidative breakage of the benzene rings to generate the carboxylate intermediate species. CoO with Co 2+ O h and ZnCo 2 O 4 with Co 3+ O h species have demonstrated good catalytic activity and high TOF Co values at low temperature. Benzene conversions for CoO and ZnCo 2 O 4 are greater than 50% at 196 and 212 °C, respectively. However, CoAl 2 O 4 with Co 2+ T d sites shows poor catalytic activity and a low TOF Co value. In addition, ZnCo 2 O 4 exhibits good durability at 500 °C and strong H 2 O resistance ability.

Driven by increasing demand for high‐energy‐density batteries for consumer electronics and electric vehicles, substantial progress is achieved in the development of long‐life lithium–sulfur (Li–S) batteries. Less attention is given to Li–S batteries with high volume energy density, which is crucial for applications in compact space. Here, a series of elastic sandwich‐structured cathode materials consisting of alternating VS2‐attached reduced graphene oxide (rGO) sheets and active sulfur layers are reported. Due to the high polarity and conductivity of VS2, a small amount of VS2 can suppress the shuttle effect of polysulfides and improve the redox kinetics of sulfur species in the whole sulfur layer. Sandwich‐structured rGO–VS2/S composites exhibit significantly improved electrochemical performance, with high discharge capacities, low polarization, and excellent cycling stability compared with their bare rGO/S counterparts. Impressively, the tap density of rGO–VS2/S with 89 wt% sulfur loading is 1.84 g cm−3, which is almost three times higher than that of rGO/S with the same sulfur content (0.63 g cm−3), and the volumetric specific capacity of the whole cell is as high as 1182.1 mA h cm−3, comparable with the state‐of‐the‐art reported for energy storage devices, demonstrating the potential for application of these composites in long‐life and high‐energy‐density Li–S batteries.

The rapidly expanding demand for sustainable and clean energy systems has inspired continuous innovation on energy storage technologies and devices. [1,2] Lithium-sulfur

A series of hybrids of nitrogen-doped graphitic porous carbon and carbon nanotubes (NGPC/NCNTs) are readily prepared in a stepwise manner by using a typical metal–organic framework (MOF-5) and urea as the carbon and nitrogen precursors, and nickel as the graphitization catalyst, respectively. These NGPC/NCNTs hybrids have demonstrated prominent catalytic activities toward oxygen reduction reaction (ORR) in alkaline medium. Compared to the benchmark Pt/C catalyst, the optimized NGPC/NCNT-900 (annealed at 900 °C) exhibits superior catalytic activity, durability and methanol tolerance, which makes it one of the best ORR electrocatalysts derived from MOFs. The promising properties in NGPC/NCNT-900 are mainly attributed to synergistic contributions of its unique hybrid structure, rich nitrogen doping, high graphitic degree, and large surface area. This attractive route for the preparation of NGPC/NCNTs holds promise for general use of a great number of available and yet rapidly growing MOFs in constructing high-performance carbon-based ORR electrocatalysts.

Nanostructured carbon materials have been extensively used for encapsulating sulfur and improving cyclic stability of lithium–sulfur (Li–S) batteries, but high carbon content and low packing density greatly limit their volumetric energy density. Herein, we present MXene-based Ti3C2T x (T x stands for the surface terminations) nanodots-interspersed Ti3C2T x nanosheet (TCD-TCS) to accomplish spatial immobilization and conversion of high-loaded sulfur species. Rich surface polar sites in TCD-TCS enhance structural integrity of the resultant electrode, while the absence of the carbon-based materials and conductive additives results in high tap density of the cathode materials. The TCD-TCS/S electrode exhibits an almost theoretical discharge capacity at a medium sulfur loading of 1.8 mg cm–2. Notably, ultrahigh volumetric capacity (1957 mAh cm–3) and high areal capacity (13.7 mAh cm–2) are synchronously achieved at a high sulfur loading of 13.8 mg cm–2. The mechanism study of sulfur evolution during discharge process highlights the importance of the integration of MXene-based nanodots and nanosheets in Li–S batteries. This proposed methodology holds great promise for the development of various high-performance energy storage materials.

Molybdenum phosphide (MoP) has received increasing attention due to its high catalytic activity in hydrogen evolution reaction (HER). However, it remains difficult to construct well‐defined MoP nanostructures with large density of active sites and high intrinsic activity. Here, a facile and general method is reported to synthesize an MoP/carbon nanotube (CNT) hybrid featuring small‐sized and well‐crystallized MoP nanoparticles uniformly coated on the sidewalls of multiwalled CNT. The MoP/CNT hybrid exhibits impressive HER activities in pH‐universal electrolytes, and requires the overpotentials as low as 83, 102, and 86 mV to achieve a cathodic current density of 10 mA cm−2 in acidic 0.5 m H2SO4, neutral 1 m phosphate buffer solution, and alkaline 1 m KOH electrolytes, respectively. It is found that the crystallinity of MoP has significant influence on HER activity. This study provides a new design strategy to construct MoP nanostructures for optimizing its catalytic performance.

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