Fluorinated pyrazoles play important roles in medicinal chemistry, drug discovery, agrochemistry, and coordination chemistry. Although fluorinated compounds have many benefits, the preparation of functionalized fluorinated pyrazoles, partly N-difluoromethylpyrazoles, remains challenging. Here, selective oxidation of the methyl group in 1-(difluoromethyl)-3-methyl-1H-pyrazole and 1-(difluoromethyl)-5-methyl-1H-pyrazoles to prepare the corresponding pyrazole-3- and pyrazole-5-carboxylic acids was described. The carboxylic acids were transformed into a broad range of new functionalized derivatives: esters, alcohols, aldehydes, amines, amides, nitriles, and chloro derivatives. The crystal structure of the initial carboxylic acid derivatives has been determined from single-crystal X-ray analysis, which provided unambiguous proof of the regiochemistry of all prepared 1-difluoromethyl-pyrazoles. Note, in the crystalline structure of substituted pyrazole-3-carboxylic acid, the formation of dimers via double hydrogen bonds of O-H···O between molecules was observed, while the pyrazole-5-carboxylic acid derivative forms chains via hydrogen bonds of O-H···NPz.

Morphological imperfections and phase segregation at the buried perovskite interface have posed significant challenges to further enhancing the efficiency of perovskite solar cells (PSCs). In this work, a halogen-functionalized porphyrin-based metal-organic framework (MOF) nanosheet, Cu-TCPP(I), is introduced as a multifunctional buffer layer at the SnO2/perovskite interface. The Cu-TCPP(I) nanosheets effectively passivate interfacial defects, regulate crystallization kinetics, and stabilize the photoactive aphase perovskite against undesirable transition to the d-phase. This interfacial engineering strategy enhances charge extraction efficiency and suppresses non-radiative recombination, enabling devices to achieve a champion power conversion efficiency (PCE) of 24.62 % with negligible hysteresis. The optimized devices retain 92 % of their initial PCE after 1600 h of storage under ambient conditions, demonstrating excellent operational stability. Importantly, the Cu-TCPP(I) interlayer exhibits strong leadchelating capability, significantly reducing the risk of lead leakage. This multifunctional interfacial design presents a promising route toward high-efficiency, stable, and environmentally friendly PSCs for largescale photovoltaic applications. (c) 2025 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Perovskite solar cells (PSCs) hold immense promise in photovoltaic technology, yet their performance and long-term stability are severely hindered by the coexistence of multiple defects. To address this critical bottleneck, we innovatively designed a host-guest composite (PMo12@γ-CD) for precursor solution doping. The unique cavity confinement effect of γ-CD precisely modulated the redox activity of PMo12, while effectively suppressing the intermolecular aggregation of PMo12. The synergistic interactions between PMo12 and γ-CD enabled the composite to integrate dual functionalities: synergistic passivation of diverse defects through coordination bonds and hydrogen bonds, and optimization of perovskite crystallization kinetics. The resultant PSCs yielded a remarkable power conversion efficiency (PCE) of 24.30 %, alongside exceptional long-term stability. After being stored in ambient conditions (25 ± 3°C, 30 % ± 10 % RH) for more than 1500 h, the PMo12@γ-CD modified device maintained 92.5 % of the primary PCE. This study leverages the structural and functional advantages of macrocyclic molecules to fully unlock the defect-repair potential of polyoxometalates (POMs), offering a novel approach to address multi-defect regulation in PSCs.

The combustion of aluminum in solid propellants is inherently hindered by its surface oxide shell, leading to ignition delay, particle agglomeration, and low combustion efficiency. Herein, an onion-structured Al@Na3Al-F6@AP composite is synthesized via a two-step evaporation-induced self-assembly process, sequentially depositing cryolite (Na3AlF6) and ammonium perchlorate (AP) onto the aluminum surface. The Na3AlF6 interlayer functions as a temperature switch inducing the transformation of the Al2O3 into Al6NaO9.5 at 700 degrees C and simultaneously exposing the active aluminum core. Therefore, the oxidation efficiency of Al@Na3AlF6 is as high as 96.75 %, significantly surpassing the values achievable by pure aluminum and conventional aluminum alloys. Furthermore, the AP-encapsulated structure of Al@Na3AlF6@AP constructs a self-sustaining oxygen supply network during aluminum combustion and reduces the diffusion time of oxidative gases to the aluminum surface by 29.6 %. As a result, the size of aggregates during Al@Na3AlF6@AP combustion is approximately 10 mu m, and the combustion heat (19.532 +/- 0.133 MJ kg-1) is 8.4 % higher than that of the physically mixed sample Al@Na3AlF6/AP. The unique onion structure and Na3AlF6 "Temperature Switch" both fundamentally reshape combustion kinetics, shifting the rate-limiting step from oxygen diffusion to aluminum oxidation activation.

Thin-film fluorescent sensors (TFFSs) suffer from low NO2 detection sensitivity and long response time due to the poor NO2 adsorption capability. Herein, a Rh6G/SnO2-SnS2/H-SiO2 TFFS with a photonic crystal structure was fabricated for NO2 sensing: Hollow SiO2 (H-SiO2) nanospheres, prepared via a sacrificial template method, formed a microporous structure and increased the specific surface area (SSA), facilitating efficient NO2 adsorption. Additionally, by modifying the H-SiO2 nanospheres with SnO2-SnS2 heterojunctions, the generated electron accumulation layer can trap escaping NO2 molecules, further improving the adsorption performance. When vertically self-assembled into a photonic crystal film (PCF), the SnO2-SnS2/H-SiO2 nanospheres could specifically amplify fluorescent signals, thereby enhancing the sensor's sensitivity. Rhodamine 6G (Rh6G) was selected as the probe molecule, and the specific nitrosation reaction was employed to optimize the selectivity of the TFFS. Dynamic fluorescent detection of NO2 gas concentrations was realized using a fiber optic spectroscopy test system. The as prepared Rh6G/SnO2-SnS2/H-SiO2 TFFS could achieve high-sensitivity room-temperature detection of NO2 in the range of 1-1000 ppm within 24 s, with a limit of detection (LOD) as low as 100 ppb. Coupled with its advantages of low cost, portability, and visual detection capability, the sensor exhibits considerable commercial potential.

Boron suffers from severely limited combustion efficiency due to the kinetic barrier imposed by its native oxide layer. In this work, a pomegranate-inspired B@(NH4)2SiF6@LiClO4 composite was fabricated via a two-step solvent evaporation-induced self-assembly strategy, enabling highly dispersed reactive domains and intimate interfacial contact. The distinctive pomegranate-inspired architecture establishes particle-level spatial organization of the reactive components, while their distinct thermal activation windows provide the temporal basis for a proposed spatiotemporally coordinated reaction pathway. TG-DSC and TG-FTIR analyses reveal that fluorine-containing species derived from (NH4)2SiF6 evolve prior to LiClO4 melting and major oxidizer release, supporting a proposed sequential fluorination-oxidation pathway involving early fluorine-mediated interfacial modification followed by oxidizer-driven boron oxidation. At an optimal (NH4)2SiF6 content of 10 wt%, the ignition delay and combustion duration are reduced by 15.47% and 68.22%, respectively, compared with B@LiClO4, demonstrating substantially improved ignition and combustion kinetics. Combined structural, thermal, and combustion analyses support the proposed spatiotemporally coordinated fluorination-oxidation pathway arising from the coupling of particle-level organization and temporally separated thermal events. This work provides a particle-level interfacial engineering strategy for coordinating fluorination and oxidation in high-performance boron-based energetic systems.

As a crucial product in the aging process of nitrate ester plasticized polyether (NEPE) propellant, the development of a non-destructive, rapid, and sensitive detection method for nitrogen dioxide (NO2) is particularly important. A coumarin-phenylhydrazone molecule with high selectivity and sensitivity to NO2 was synthesized. By employing a hydrazone group as the recognition site that specifically reacts with NO2, the ratiometric fluorescence responses in both solution and film were realized. Upon NO2 exposure, the absorption and fluorescence emission bands of the probe possess a significant hypsochromic shift. In addition to achieving a linear response to NO2 under solution conditions, the probe can also achieve a linear response to NO2 under film conditions that are convenient for practical applications. Furthermore, the probe has excellent selectivity and thermal stability, and the limit of detection (LOD) is as low as 1.5 ppm, which broadens the boundaries of practical applications. In this study, the coumarin probe was firstly extended to the field of solid propellant aging monitoring, which has the potential of being applied for the non-destructive monitoring of NEPE propellant aging.

As categories of promising semiconductor photocatalysts, the bismuth-based semiconductors still have some defects for influencing their extensive application in the photodegradation of refractory pollutants, such as limited light response capability, slow charge transport rate and severe carrier recombination probability. In this work, a novel BiOBr/CeMo8O14/r-GO (BCG) S-scheme heterojunction was synthesized via a continuous hydrothermal method and employed as a photocatalyst to activate peroxymonosulfate (PMS) for the photodegradation of levofloxacin (LFX). The photodegradation efficiency of LFX by the optimal BCG reaches up to 91.8%, which is approximately twice that of pure BiOBr (merely 46.4%). This can mainly be ascribed to the formation of the S-scheme heterojunction between BiOBr and CeMo8O14, finally promoting the transfer of photogenerated charges, prolonging the carrier lifetime, and offering abundant reactive sites for the activation of PMS. Furthermore, the r-GO serves as an additional electron transfer pathway for effectively accelerating the charge transfer rate within BCG. The free radical capture experiment and electron spin resonance (ESR) measurement verify that ·O2− and 1O2 are the main reactive oxygen species (ROS) for governing the photodegradation process. Density functional theory (DFT) calculation and Kelvin probe force microscopy (KPFM) measurement were performed to elucidate the charge transfer process in BCG and the existence of internal electric field (IEF) between monomers, finally verifying the successful construction of S-scheme heterojunction. Consequently, this research offers an effective approach for the rational fabrication of bismuth-based S-scheme heterojunction photocatalysts featuring efficient photocatalytic performance.

Optimizing perovskite solar cells (PSCs) demands a comprehensive strategy to simultaneously mitigate spectral mismatch and film defects. Herein, we propose a rationally designed white-light-emitting ternary lanthanide metal-organic framework (Etg-dpon) as a dual-functional additive, surpassing the constraints of conventional monochromatic luminophores. By leveraging the antenna effect, controlled sensitization of Eu3+ and Tb3+ ions within a Gd-based host yields a single-phase white-light emitter with precise energy level alignment and efficient multi-color emission. On the one hand, its matched emission spectrum realizes efficient Fo & uml;rster resonance energy transfer (FRET) down-conversion, which converts harmful high-energy ultraviolet photons into available visible light to broaden solar spectral utilization range. On the other hand, abundant surface active sites of Etg-dpon can effectively modulate perovskite crystallization behavior and passivate interfacial and bulk defects simultaneously. Benefiting from the above synergistic optical regulation and morphology optimization effects, the optimized PSC delivers a champion power conversion efficiency of 23.61%, and exhibits greatly improved ultraviolet irradiation stability, retaining 78% of its initial PCE after 36 h of continuous 310 nm irradiation. This study underscores the potential of designed white-light MOFs, offering a synergistic solution to optical, morphological, and stability challenges in high-performance PSCs.

Nitronyl nitroxides (NNs) are widely employed in chemistry, physics, and materials science due to their inherently high stability and magnetic properties. However, the synthesis of C(2)-organoelement derivatives remains a challenging task. This paper reports on the efficient synthesis and characterization of an unusual organosilver complex consisting of the [Ag–(IPr)2]+ cation and the [Ag–(NN)2]− anion. The salt [Ag–(IPr)2][Ag–(NN)2] was prepared in high yields (88–96%) by two synthetic routes: by reacting the carbene ligand precursor IPr·HCl with Ag2O and nitronyl nitroxide NN–H, or by addition of NN–H/tBuONa to a THF solution of IPrAgCl (generated in situ from IPr·HCl and Ag2O) under microwave irradiation. Electrochemical analysis of [Ag–(IPr)2][Ag–(NN)2] revealed a reversible one-electron oxidation peak at E1/2 = −0.258 V and an irreversible reduction peak at Ep = −2.169 V, which is likely related to the electrochemical transformation of the nitronyl nitroxide moieties. Crystallization from an acetone/benzene solution yielded crystals of [Ag–(IPr)2][Ag–(NN)2]·2H2O solvate, in which the diradical anion [Ag–(NN)2]− is bound to two water molecules by hydrogen bonds. These hydrogen bonds stabilize a planar conformation of the [Ag–(NN)2]− anion, in which both NN fragments lie in the same plane and, according to DFT calculations, are linked by fairly strong antiferromagnetic interaction. DFT calculations also predict the dissociation of the complex with water in toluene solution and a conformational change leading to the appearance of about 90° between NN fragments and a significant decrease in exchange interaction.

Hydroxylammonium nitrate-based electrically controlled solid propellants (HAN-ECSP) combine safety and thrust controllability but suffer from low energy output and incomplete combustion due to HAN's limited thermal stability and a lack of compatible fuels. This study introduces a fuel-oxidizer integrated ionic liquid (IL) 1-ethyl-3-methylimidazolium perchlorate ([Emim][ClO4]) into HAN-ECSP formulations to enhance electrically controlled combustion performance. The [Emim](+) cation scavenges electrophilic radicals, suppressing premature HAN decomposition during early thermal stages. In the process of electrically controlled combustion, the degradation of [Emim](+) occurred due to the center dot OH radicals that were generated at the anode during electrification, subsequently promoting combustion. Simultaneously, it rapidly amalgamated with the free radicals produced during the combustion process to terminate chain reactions upon power interruption. This mechanism significantly reduced both ignition and extinguishment delays to less than 100 ms-a duration notably shorter than that observed in conventional HAN-ECSPs. Additionally, this method eliminated the traditional reliance on water for flame extinguishment. The oxidizer ClO4- shifts the decomposition temperature range of Polyvinyl alcohol to lower temperatures and enhances its degree of decomposition. Through their synergistic action, the IL-ECSP achieve a more thorough thermal decomposition and a more concentrated heat release profile. The volumetric combustion heat of 20%IL-ECSP reached 16,687.06 J/cm(3), which was 70% higher than that of ECSP without IL (9835.45 J/cm(3)). Moreover, increasing the [Emim][ClO4] content broadens the voltage-regulated range of the propellant's average burning rate and yields higher average burning rates and combustion temperatures during burning. This work therefore presents a novel formulation strategy for HAN-ECSPs that enhances energy output while preserving excellent electrical controllability.

Hydroxylammonium nitrate-based electrically controlled solid propellant (HAN-ECSP) has garnered significant research interest due to its high energy density and at-will on-off capability. In this study, combustion tests revealed that the ignition delay time and mass combustion rate of the propellant vary depending on the electrode materials (Cu, Ni, Ti, and Ta). To investigate the underlying mechanisms behind these variations, electrochemical properties and decomposition performance were also achieved, which can also quickly evaluate and select electrodes in HAN-ECSP. Among these tested electrodes, Cu exhibited the best performance, with an ignition delay time of 0.77 s. Further electrochemical analysis showed that Cu electrodes provided the highest conductivity (4.05 S/m), lowest overpotential (1.10 V), and highest double-layer capacitance (2.79 & times; 10-4 F & centerdot;m-2). Additionally, combustion tests revealed that the Cu electrode led to the highest gas pressures and the highest concentration of H2 under all applied voltages. These findings suggest that Cu is the most suitable electrode material for HAN-ECSP. Moreover, the composition and concentration of major gases produced during the decomposition of propellant further elucidated its combustion behavior. The results indicate that the ignition delay time is strongly correlated with the concentration of H2, while the combustion duration is influenced by the concentration of O2. Overall, this study establishes a clear connection between the electrochemical and decomposition properties of HAN-ECSP and its combustion performance, offering valuable insights into electrode material selection.

The development of low-cost and highly active non-noble metal based bifunctional electrocatalysts for overall water splitting is quite crucial for advancing the effective utilization of hydrogen energy. Herein, on the basis of CeF3 monomer, a novel bifunctional electrocatalyst (Mn(BTC),Se-CeF3) with a nanosheet core-shell structure was successfully synthesized through Mn doping from the Mn-BTC deconstruction induced by strong F– coordination under hydrothermal conditions and Se doping during high-temperature annealing. The developed Mn(BTC),Se-CeF3 displays excellent electrocatalytic activities for oxygen evolution reaction and hydrogen evolution reaction (OER and HER) in alkaline conditions, delivering an overpotential of 259 and 98 mV for achieving a current density of 10 mA/cm2, respectively. Collectively, the Mn(BTC),Se-CeF3 based electrolytic cell confirms a superior overall water splitting performance, merely requiring an applied potential of 1.553 V for attaining a current density of 10 mA/cm2. Apart from this, it demonstrates remarkable stability during continuous electrolysis for over 100 h. Density functional theory (DFT) calculations reveal that Mn and Se co-doping effectively activates the Ce sites in CeF3, synergistically enhancing both HER and OER activities. Mn incorporation triggers electron redistribution around Ce sites and Se then synergizes with Mn to fine-tune the electron density of Ce, finally enhancing the HER and OER activity of CeF3 and lowering the electrochemical energy barrier in rate-determining steps (RDS). This work not only proposes a novel strategy but also provides valuable insights for designing high-performance rare earth metals-based bifunctional water-splitting electrocatalysts.

Al–Li alloy fuels are attractive high-energy additives for solid propellants because their micro-explosion behavior can mitigate the severe agglomeration commonly encountered in aluminum fuels. However, their practical application remains constrained by hydrolysis, poor compatibility with binder/plasticizer matrices, and incomplete suppression of condensed-phase agglomeration during combustion. Herein, we propose a spatially integrated rigid–flexible interphase engineering strategy to reconcile the stability–reactivity trade-off of Al–Li alloy particles. Through interfacial thiol–ene click coupling and UV-initiated HFA–OVS radical grafting, rigid siloxane scaffolds and fluorinated polymer segments were spatially integrated within the same nanoscale interphase. Compared with the Al–Li@OVS@PHFA, the spatially integrated Al–Li@(OVS/PHFA) interphase exhibits stronger Si/F spatial association, higher interfacial binding, and improved structural continuity. Consequently, Al–Li@(OVS/PHFA) reduces hydrolytic gas generation by 95.9%, decreases hygrothermal weight gain from 187.61% to 3.27% after 30 d, and retains 97.5% of its energetic value. In BTTN compatibility tests, gas generation decreases from 62.52 to 1.09 mL g−1, corresponding to a 98.3% reduction. More importantly, this protective interphase remains combustion-accessible, shortening the ignition delay by 70.7%, reducing the combustion duration by 46.2%, and further decreasing the agglomerate D50 from 294.92 to 95.29 μm compared with pristine Al–Li. In propellants, Al–Li@(OVS/PHFA) delivers an apparent linear burning rate of 1.477 mm s−1 and a heat of explosion of 11,496.1 J g−1, further increasing these values by 6.2% and 10.9% compared with the stepwise Al–Li@OVS@PHFA counterpart. This work demonstrates that nanoscale spatial organization of rigid and flexible interfacial components can transform a protective coating into a multifunctional interphase that integrates environmental shielding, formulation compatibility, and combustion-stage activation, providing an architecture-guided route toward high-performance reactive metal fuels.

Indirect control of combustion through magnetic fields presents a novel approach to achieving adjustable propellant characteristics. This study examines the feasibility of regulating the combustion behavior of a Nitromethane (NM)-based gel propellant by incorporating magnetic particles and applying external magnetic fields. The results indicate that the propellant containing magnetic functional iron-based nanospheres (MFIS) shows a unique magnetic-field-dependent combustion response in an open environment. By adjusting the MFIS particle content and the strength of the magnetic field, the burning rate can be effectively modulated, demonstrating controllable behavior. For instance, under the magnetic field produced by a ring of four magnetic tiles with a central through-hole, the burning rate of the propellant in an N52 NdFeB permanent magnet decreased from 1.072 mm/s to 0.521 mm/s, representing a combustion rate reduction ratio of 51.40%. Further analysis suggests that the magnetic field plays a significant role: It induces the aggregation of magnetic particles at the burning surface, thereby hindering mass and heat transfer. These findings demonstrate the potential of magnetic-field-assisted control of propellant combustion and provide a basis for future variable-thrust propulsion applications.

High-sensitivity fluorescent sensing of nitrogen dioxide (NO2) gas at room temperature remains a critical challenge to be overcome currently. In this work, a thin-film device (TFD) based on photonic-crystal film (PCF) was synthesized for the fluorescence sensing of NO2 (1-100 ppm) with a 120 s response time, and exhibited obvious signal feedback to NO2 concentration as low as 100 ppb. A wealth of experimental data indicates that its ultrahigh sensitivity primarily originates from the following aspects. The structure of the PCF leads to the enhancement of the fluorescence signal, and the SiO2 nanospheres constituting the PCF increase the surface area of the TFD, laying a solid foundation for detection. By inducing the SnO2-SnS2 heterojunction on SiO2 nano-spheres, the TFD can efficiently capture NO2 molecules and convert them into NO2-, facilitating detection. Furthermore, Rhodamine 6G (R6G) is selected as the probe molecule, which is commercially available and has excellent physicochemical properties for the sensing of NO2, endowing the TFD with high selectivity. The prepared SnO2-SnS2/SiO2 TFD demonstrates promising application prospects in the context for visualizable detection of low-concentration NO2 in explosive production and storage workshops, coal mines, and other high-explosive environments.

The in situ polymerization method for coating Al–Li alloy exhibits great potential for applications in aerospace and weapon fields as it improves the compatibility, stability and combustibility of Al–Li in solid propellants.

Nanographenes with diverse topological structures have shown enormous potential in fields such as photonics, optoelectronics, and spintronics. This work employs a "from-core-to-branch" strategy to controllably synthesize star-shaped nanographenes with various symmmetries. The obtained star-shaped nanographenes exhibit symmetry-dependent HOMO-LUMO gaps and photoluminescence quantum yields, revealing the importance of precisely controlling the molecular topologies. This work opens a new avenue to expand the chemical space of star-shaped nanographenes with tunable properties.

The oxide layer on the Al particle surface seriously limits application in solid propellants, resulting in low combustion efficiency. This work prepares a series of Al decorated by nano-silver (namely Al/Ag) via in-situ reduction to enhance combustion performance Thanks to silver's smaller specific heat capacity, surplus heat energy is transferred to the Al core through a tight combination with decorated noble metal nanoparticles. Along with the intermetallic reaction, the thermal stress on Al would accelerate the oxide shell rupture to reduce the oxygen gas diffusion barrier during combustion. The oxidation temperature of Al/Ag-2 composites decreases from 1017.3 degrees C to 982.93 degrees C. Hence, the combustion performance of solid propellants containing Al/Ag composites is improved with the higher maximum flame temperature and emission spectra intensity. In addition, the thermal decomposition of ammonium perchlorate (AP) is catalyzed via nano-silver. The combustion efficiency of the propellant containing Al/Ag-2 is effectively improved by the synergistic effect in which the potential energy from Al and AP is exploited as far as possible. This work demonstrates that metal surface modification significantly improves the combustion performance of solid propellants.