Latest ArticlesA pseudocapacitance dominated anode material assembled from Li3VO4 nanocrystals encapsulated in the interlayers of N-doped graphene has been developed via a facile 2D nanospace confined strategy for lithium ion capacitors (LICs). In this contribution, the N-doped graphene synthesized by a faicle solid state reaction using C3N4 nanosheets as template and glucose as carbon source provides sufficient 2D nanospace for the confined and homogeneous growth of Li3VO4 at the nanoscale, and simultaneously efficiently anchors each nanobuilding block inside the interlayers, thus realizing the utilizaiton of full potential of active components. The so-formed 3D hybrids not only ensure intimate electronic coupling between active materials and N-doped graphene, but also realize robust structure integrity. Owing to these unique advantages, the resulting hybrids show pseudocapacitance dominated lithium storage behaviors with capacitive contributions of over 90% at both low and high current rates. The LVO@C@NG delivers reversible capacities of 206 mAh/g at 10 A/g, capacity retention of 92.7% after 1000 cycles at 2 A/g, and a high energy density of 113.6 Wh/kg at 231.8 W/kg for LICs.
The three-way catalyst (TWC), as a promising approach to control automobile exhaust emission, has been widely studied and applied. However, it still suffers from the high light-off temperature and poor stability. Herein, we synthesized a multicomponent catalyst Rh/Cu-CeSn by using Cu metal doping to modify the Ce-based solid solution, which exhibited good TWC catalytic performance: the light-off temperatures for CO, NO, and C3H6 conversion are 172 ℃, 266 ℃, and 193 ℃, respectively. Moreover, the catalyst still maintained good activity after 12 h of the continuous reaction under high-temperature conditions. The experiments and mechanism studies reveal that due to the redox pair Cu+/Cu2+, the Cu incorporation can effectively inhibit the Rh transition to the oxidation state and greatly enhance the catalytic activity and stability. This work provides a viable strategy for precise characteristic modulation of composite oxide supports during the fabrication of noble metal-based catalysts, which significantly reduces environmental pollution from energy applications.
Na3V2(PO4)3 (NVP) is regarded as alternative cathode material for sodium-ion batteries (SIBs) due to its potential high-rate performance and pronounced long-term cycle stability. However, electronic conductivity and tap density are difficult to be balanced. Herein, we report that high-temperature shock (HTS) can prepare "single crystalline like" NVP which combines high-rate capability with high tap density together into one with the assistance of carbon framework and large particle. Thus, high reversible capacity of 110 mAh/g at 0.1 C with 89.9% capacity retention after 1600 cycles at 1 C and specific capacity of 83.5 mAh/g at 50 C rate has been exhibited. This study provides a novel strategy to guide the production of high tap density, and rate performance polyanionic cathode materials.
Skins expose to kinds of risk factors for damage, such as the hormone drugs, skin care products and ultraviolet radiation, which is accompanied by the production of excessive reactive oxygen species (ROS) and eventually leads to hypertrichosis. This skin disease is not aesthetically pleasing and even causes psychological and spiritual problems such as inferiority, anxiety and irritability. Current therapies are limited and often unsatisfactory, such as pharmacological and physical therapies, which have adverse effects and cause the irreversible destruction of hair follicles. Gold nanoclusters have good biocompatibility and their biosynthesis in vivo is responsive to oxidative stress microenvironment (OSM), which could be a safe and effective drug for ROS-induced skin injury. In our study, we demonstrated that zero valence fluorescent gold nanoclusters (FGNCs) were in situ biosynthesized in the plucking-induced damaged skin but not in the normal skin after the administration of gold precursors (+3), while FGNCs inhibited hair follicle regeneration by negatively regulating nuclear transcription factor kappa B (NFκB)-mediated inflammatory response signaling pathway (NFκB/tumor necrosis factor-α (TNF-α) axis). This OSM-responsive in situ biosynthesis method is facile and safe and holds great promise for curing hypertrichosis associated with skin dermatitis and injury.
Chiral coordination molecular cages/capsules with discrete nanoconfined chiral cavities demonstrate significant potential applications across various fields. In this study, we utilized Tröger's base as the building block to design and synthesize two pairs of enantiopure ligands. These ligands were then self-assembled with Pd(Ⅱ) ions through chiral self-sorting coordination, resulting in the formation of two pairs of homochiral M2L4-type coordination molecular capsules. Notably, due to differences in the substitution positions on the Tröger's base, these two pairs of enantiomeric coordination molecular capsules exhibited distinct levels of cavity closures, cavity sizes, and host-guest recognition properties. This research offers valuable insights into the construction of novel chiral molecular capsules and the regulation of confined cavities.
Synergy strategy of photocatalysts and polymer resins are promising technology for marine antifouling. However, it is still a main challenge to obtain a green, safe, and efficient antifouling coatings. Herein, carbon (graphene or CNT) modified TiO2 photocatalyst was synthesized via hydrothermal and annealing process and has successfully applied in acrylate fluoroboron polymer (ABFP) composite coating. Morphology and chemical composition were detailed characterized. The graphene or CNT acted as a bridge with supplemental spatial structures (petal gaps, entanglement) and new functional groups (CO, CTiO, etc.) on TiO2 particle. Carbon nanotube (CNT) modified TiO2-ABFP coatings (BTCP) achieved excellent antibacterial and anti-diatom adhesion rate of 89.3%–96.70% and 99.00%–99.50%, which was 1.84–4.94-fold more than that of the single ABFP. CNT or graphene served as electronic bridges was considered as the crucial mechanism, which significantly improved the light absorption range and capacity, conductivity, and photoelectric response of TiO2, and further accelerated the generation and transfer of free radicals to the surface of BTCP or FTGP. Moreover, the improvement of catalyst activity synergizes with the smooth surface, hydrophilicity, and slow hydrolysis of composite coatings, achieved long-term and efficient antifouling performance. This work provides a new insight into the modification of TiO2 and antifouling mechanism of polymer coating.
Gold-catalyzed amination reactions based on azides via α-imino gold carbene intermediates have attracted extensive attention in the past decades because this methodology leads to the facile and efficient construction of synthetically useful N-containing molecules, especially valuable N-heterocycles. However, successful examples of intermolecular generation of α-imino gold carbenes by using azides as amination reagents are rarely explored probably due to the weak nucleophilicity of azides. Herein, we disclose an efficient gold-catalyzed intermolecular aminative cyclopropanation of ynamides with the allyl azides, enabling flexible synthesis of a wide range of valuable 3-azabicyclo[3.1.0]hex-2-ene derivatives in good to excellent yields with excellent diastereoselectivities. Importantly, this protocol represents the first use of allyl azide as an efficient amination reagent in gold-catalyzed alkyne amination reactions.
In this study, we proposed a novel and efficient way to strengthen polyvinyl alcohol (PVA) fiber using graphene quantum dots (GQDs). PVA molecular chains were grafted onto the surface of GQDs through Friedel-Crafts alkylation reaction to obtain functionalized GQDs (f-GQDs), and PVA/f-GQDs composite fiber was successfully prepared by wet spinning and post-treatment. The tensile strength and Young’s modulus of the composite fiber reached up to 1229.24 MPa and 35.36 GPa which were approximately twice and 4 times those of the pure PVA fiber, respectively. Moreover, the composite fiber was demonstrated excellent resistance to solvents. In addition, the PVA/f-GQDs composite fiber showed intense and uniform cyan fluorescence, meanwhile, it could maintain stable solid-state fluorescence in acid and alkali solutions and particularly after long-term immersion in water (1 month). This study proposes a promising route for obtaining high-performance conventional fibers with some new functions.
Carbon dots (CDs), due to their low cost, high stability, and high luminous efficiency, have emerged as an excellent material for the emissive layer in next-generation electroluminescent light-emitting diodes (ELEDs). However, improving the efficiency of fluorescent CDs-based ELEDs remains challenging, primarily because it is difficult to utilize triplet excitons in the electroluminescence process. Therefore, enhancing the exciton utilization efficiency of CDs during electroluminescence is crucial. Based on this, we exploited the characteristic large exciton binding energy commonly found in CDs to develop exciton-emitting CDs. These CDs facilitate the radiative recombination of excitons during electroluminescence, thereby improving the electroluminescent efficiency. By rationally selecting precursors, we developed high quantum efficiency CDs and subsequently constructed CDs-based ELEDs. The blue-light device exhibited an external quantum efficiency of over 4%. This study introduces a novel design concept for CDs, providing a new strategy for developing high-performance blue ELEDs based on CDs.
Herein, the Cu(Ⅲ) synthesized from copper plating effluent was developed for the first time to evaluate the onsite degradation performance of heavy metal complexes in the wastewater, thus achieving the purpose of "treating waste with waste". The results indicated that synthetic Cu(Ⅲ) presented the excellent decomplexation performance for Cu(Ⅱ)/Ni(Ⅱ)-organic complexes. The removal efficiency of Cu(Ⅱ)/Ni(Ⅱ)-EDTA significantly increased with increasing Cu(Ⅲ) dosage, and the degradation of Cu(Ⅱ)/Ni(Ⅱ)-EDTA by synthetic Cu(Ⅲ) system displayed highly pH-dependent reactivity. The radical quencher experiments confirmed that Cu(Ⅲ) direct oxidation were mainly involved in the degradation of Cu(Ⅱ)-EDTA. Additionally, the continuous decarboxylation process was proven to be the main degradation pathway of Cu(Ⅱ)-EDTA in Cu(Ⅲ) system. The coexisting substances (SO42−, Cl− and fulvic acids) showed little impacts at low level for the removal of Cu(Ⅱ)/Ni(Ⅱ)-EDTA, while retarded the degradation of Cu(Ⅱ)-EDTA slightly at high level, which features high selective oxidation. Encouragingly, it was also effective to remove Cu(Ⅱ)/Ni(Ⅱ)-EDTA from in treating actual Cu/Ni-containing wastewater through synthetic Cu(Ⅲ) treatment.