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Catalytic technologies are pivotal in enhancing energy efficiency, promoting clean energy production, and reducing energy consumption in the chemical industry. The pursuit of novel catalysts for renewable energy is a long-term goal for researchers. In this work, we synthesized three two-dimensional covalent organic frameworks (COFs) featuring electron-rich carbazole-based architectures and evaluated their catalytic performance in photocatalytic organic reactions and electrocatalytic oxygen reduction reactions (ORRs). Pyrene-functionalized COF, termed as FCTD-TAPy, demonstrated excellent photocatalytic performance for amino oxidation coupling and showed a remarkable preference for substrates with electron-withdrawing groups (up to >99% Conv. and >99% Sel). Furthermore, FCTD-TAPy favored a four-electron transfer pathway during the ORR and exhibited favorable reaction kinetics (51.07 mV/dec) and a high turnover frequency (0.011 s−1). In contrast, the ORR of benzothiadiazole-based FCTD-TABT favored a two-electron transfer pathway, which exhibited a maximum double-layer capacitance of 14.26 mF cm−2, a Tafel slope of 53.01 mV/dec, and a hydrogen peroxide generation rate of 70.3 mmol g−1 h−1. This work underscores the potential of carbazole-based COFs as advanced catalytic materials and offers new insights into the design of metal-free COFs for enhanced catalytic performance. [ABSTRACT FROM AUTHOR]

The practical application of hard carbon in sodium‐ion batteries is limited by insufficient reversible capacity and low initial Coulombic efficiency (ICE), which are caused by the lack of active sites and unstable electrode/electrolyte interface. Herein, a biomass‐derived hard carbon material based on tea stems is proposed, which exhibits an ultrahigh ICE of 90.8%. This remarkable ICE is attributed to the presence of an inorganic‐rich, thin, and robust solid electrolyte interface (SEI) layer. Furthermore, the material demonstrates excellent cycling stability, showing a capacity retention of 99.5% after 500 cycles at 280 mA g−1. Additionally, when it works as the anode material in a sodium‐ion full cell without presodiation, it reaches a high energy density of 212 Wh kg−1 and a superior stability, e.g., retaining 93.1 mAh g−1 after 1000 cycles at 1 A g−1 with a capacity retention of 91.3%. The sodium storage capacity of this material is primarily attributed to a combined adsorption‐intercalation/filling effect as confirmed by in situ XRD and ex situ Raman analyses. These findings make this biomass‐derived hard carbon material a promising candidate for commercial application of sodium‐ion batteries, achieving high performance at low cost. [ABSTRACT FROM AUTHOR]

Four new unusual pentacyclic triterpenoids (1–4) were isolated from the roots of Jasminum sambac (L.) Ait. Their structures were elucidated by 1D and 2D NMR analysis, single-crystal X-ray diffraction and HRESIMS. [ABSTRACT FROM AUTHOR]

Cu2O is a p-type direct bandgap semiconductor with a band gap of 2~2.2 eV, which has excellent visible light absorption and utilization. However, slow charge transfer and poor stability hinder its practical application. In this paper, a facile electrodeposition approach successfully synthesized the heterostructure of p-Cu2O and n-Cu2O. The protective layer of n-Cu2O on the surface of p-Cu2O nanoparticles forms a p/n heterojunction. Due to the p/n heterojunction, the PEC performance of p/n-Cu2O is enhanced significantly. The charge separation efficiency of photogenerated electron/hole pairs in p/n-Cu2O is greatly improved. Therefore, p/n-Cu2O shows superior photoelectrochemical (PEC) CO2 reduction reaction (CO2RR) efficiency when used as a photocathode. [ABSTRACT FROM AUTHOR]

A novel polyoxovanadate, which is synthesized from the hydrothermal treatment of barbiturate acid, is presented. The structural features of these are discussed.

Li/CFx cells possess the highest energy density among all lithium primary batteries. Here, the electrochemical lithiation process is elucidated through high-resolution 19F NMR, in situ7Li NMR and TEM methods. Fluorinated carbon CFL (L is around 0.06 or less) is identified for the first time to be generated in the discharge process of CFx (x ≥ 0.5) besides LiF and carbon. Moreover, the morphological evolution of the formed LiF, which affects the impedance of the battery during discharge, is illustrated as crystal nuclei of LiF, with a size of around 10 nm, which keep forming and growing into crystal grains of LiF, with a size of around 200 nm, until the surface of the CFx particles is saturated by LiF and then both crystal nuclei and grains enlarged promptly towards the end of lithiation. This work reveals the electrochemical reaction mechanism of CFx and provides crucial guidance to enhance the performance of the materials. [ABSTRACT FROM AUTHOR]

Abstract Although phosphorus exhibits a high lithium uptake, its poor cycling performance and low coulombic efficiency limit its application for lithium-ion batteries. Herein, ex -situ solid-state 31P and 7Li NMR studies together with XRD measurement are performed to provide a deep insight into the amorphous Li-P alloys and amorphous-to-crystalline transformation process. The amorphous Li 3 P and overlithiated Li 3+x P phases are firstly experimentally detected. The evolution and coexistence of various Li-P alloys intermediates including overlithiated Li 3+x P upon lithiation, and the recovery of the Li-P alloys intermediates to the initial phosphorus after delithiation are observed. Our results also disclose for the first time that partial LiP 7 phase and Li 3 PO 4 resulting from slight surface oxidation of rP still retain at the end of charge, which are highly relevant to the low coulombic efficiency in the first cycle and the successive decay of the performance. This study provides some insights into the specific multi-phase evolution mechanism of alloying anodes that may be generally involved in conversion-type electrode materials for Li batteries. Graphical abstract fx1 Highlights • The electrochemical phase change of red phosphorus for lithium ion batteries is elucidated. • The amorphous Li3P and overlithiated Li3 + xP structures are firstly experimentally detected. • Multiple Li-P alloys phases are coexisted across the whole electrochemical process. • Partial LiP 7 and Li 3 PO 4 still retain in the end of charge, causing a low coulombic efficiency beyond the formation of SEI. [ABSTRACT FROM AUTHOR]

K2TiF6:Mn4+ is a highly efficient narrow‐band emission red phosphor with promising applications in white light‐emitting diodes (LEDs) and wide‐gamut displays. Nevertheless, the poor moisture‐resistant properties of this material hinder commercialization. A convenient reverse cation‐exchange strategy is introduced for constructing a core–shell‐structured K2TiF6:Mn4+@K2TiF6 phosphor. The outer K2TiF6 shell acts as a shield for preventing moisture in the air from hydrolyzing the internal MnF62− group, while effectively cutting off the path of energy migration to surface defects, thereby increasing the emission efficiency (especially for the phosphors doped with high concentrations of Mn4+). Employed as a red phosphor, the packaged white LED exhibits an extraordinarily high luminous efficacy of 162 lm W−1, a correlated color temperature (CCT) of 3510 K, and a color rendering index of 93 (Ra). Aging tests performed on this device at 85 °C and 85 % humidity for 480 h retain up to 89 % luminous efficacy. The findings could facilitate commercial application of K2TiF6:Mn4+@K2TiF6 phosphor. A reverse cation‐exchange strategy is presented for the construction of a core–shell‐structured K2TiF6:Mn4+@K2TiF6 (KTF:Mn4+@KTF) phosphor. The KTF shell shields the KTF:Mn4+ core from ambient moisture and prevents hydrolysis of the internal MnF62− group. The phosphor exhibits a high photoluminescence quantum yield and excellent moisture‐resistant properties. [ABSTRACT FROM AUTHOR]

Herein, we report a reliable method for the synthesis of nanohybrids with interconnected networks of reduced graphene oxide (rGO) enwrapping hollow SnO2 nanospheres (H-SnO2@rGO), which is implemented by an electrostatic assembly process between positively charged hollow SnO2 nanospheres and negatively charged rGO. Systematic characterizations demonstrate that the as-developed H-SnO2@rGO has a unique three-dimensional (3D) nanostructure with favorable features for lithium ions storage, which not only provides robust protection against the aggregation and volume changes of the SnO2 nanospheres, but also ensures high transport kinetics for both electrons and lithium ions. The as-developed H-SnO2@rGO exhibits an outstanding electrochemical performance as an anode material for lithium-ion batteries, showing a high reversible capacity of 1107 mA h g−1 after 100 cycles at a current density of 0.1 A g−1 and maintaining 552 mA h g−1 over 500 cycles at a current density up to 1 A g−1. [ABSTRACT FROM AUTHOR]

Group IVB ions (Ti4+ and Zr4+) are employed to modify solution growth of W18O49 nanocrystals. In the presence of group IVB ions, the morphology of the produced monoclinic W18O49 nanocrystals can be modulated from inhomogeneous shapes to uniform an ultrathin nanobelt with the ( [ABSTRACT FROM AUTHOR]

Abstract: MnWO4 nanoplates with ionic conductivity were synthesized under hydrothermal condition. In particular, the ionic conductivity of MnWO4 nanoplates is based on the ionic conduction and hygroscopic character in moist atmosphere. When the water molecules are adsorbed, the conductance of MnWO4 will change. At room temperature, the electric capability of MnWO4 is very good (the conductance is 1.46×10−5 Scm−1). After being heated for 4h at 100°C, the conductance of MnWO4 becomes so small that it is on the verge of nonconductor. The water molecules play an important role in the electric conduction of MnWO4. Based on this character, MnWO4 can be used as humidity sensing material, and its possible humidity sensing mechanism is investigated in this paper. [Copyright &y& Elsevier]

A new oxalato- and acetato-bridged Mn(II) polymer, [Mn2(C12N2H8)2( μ-C2O4)( μ-CH3COO)2] n ·4 nH2O was synthesized and characterized by X-ray diffraction analysis. The compound exhibits a one-dimensional chain-like structure, in which the Mn atom is coordinated by two nitrogen atoms and four carboxyl oxygen atoms with octahedral coordination geometry. As far as we are aware, this type of coordination polymer involving the simultaneously bridging oxalate and acetate ligands has not been studied so far. [ABSTRACT FROM AUTHOR]

A new one-dimensional molybdenum oxide compound with manganese-o-phen subunit: [Mn(o-phen)(H2O)MoO4]·H2O (1) (o-phen=o-phenanthroline) was synthesized by thehydrothermal reaction of Na2MoO4·2H2O, MnSO4·H2O, oxalic acid, o-phenanthroline (o-phen) and water. Its structure was determined by elemental analyses, ESR spectrum, TG analysis, IR spectrum and single-crystal X-ray diffraction. Compound 1 crystallizes in triclinic system, space group P-1 with a=7.0401(2) Å, b=10.4498(2) Å, c=10.5720(2) Å, α=73.26(7)°, β=83.34(8)°, γ=77.33(9)°, V=725.5089(0) Å3, Z=2, and R1=0.0322 for 2337 observed reflections. Compound 1 exhibits one-dimensional chain structure. The chains are linked up via hydrogen bonding to 2D layers, which are further assembled through π–π stacking interactions to a 3D supermolecular structure. [Copyright &y& Elsevier]

Four heterometal complexes, namely {(NH4)2[(VIVO)2(μ2-O)(nta)2Mn(H2O)4] · 2H2O}n (1), {(NH4)2[(VIVO)2(μ2–O)(nta)2Zn(H2O)4] · 2H2O}n (2), NH4[La(H2O)9][(VIVO)2(μ2–O)(nta)2] (3) and NH4[Nd(H2O)9][(VIVO)2(μ2–O)(nta)2] (4), where nta=nitrilotriacetate, have been prepared and characterized by single-crystal X-ray diffraction analyses. Complexes 1 and 2 exhibit heterometallic one-dimensional chain structures formed by polymeric [(VIVO)2(μ2-O)(nta)2M(H2O)4]2- anions (M=Mn, Zn). Moreover, the one-dimensional chains are further linked together through hydrogen bonding into a three-dimensional framework. Compounds 3 and 4 display discrete units, however, these molecules are built up into three-dimensional structures through hydrogen bonding. [Copyright &y& Elsevier]