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Efficient dispersion of nanoparticles (NPs) is a crucial challenge in the preparation and application of composites that contain NPs, particularly in coatings, inks, and related materials. Physical adsorption and chemical modification are the two common methods used to disperse NPs. However, the former suffers from desorption, and the latter is more specific and has limited versatility. To address these issues, we developed a novel photo-cross-linked polymeric dispersant, comb-shaped benzophenone-containing poly(ether amine) (bPEA), using a one-pot nucleophilic/cyclic-opening addition reaction. The results demonstrated that the bPEA dispersant forms a dense and stable shell on the surface of pigment NPs through physical adsorption and subsequent chemical photo-cross-linking, which effectively overcome the drawbacks of the desorption occurred in physical adsorption and the specificity of the chemical modification. By means of the dispersing effect of bPEA, the obtained pigment dispersions show high solvent, thermal, and pH stability without flocculation during storage. Moreover, the NPs dispersants show good compatibility with screen printing, coating, and 3D printing, endowing the ornamental products with high uniformity, color fastness, and less color shading. These properties make bPEA dispersants ideal candidates in fabrication dispersions of other NPs.
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Lightweight polymer-based nanostructured aerogels are crucial for electromagnetic interference (EMI) shielding to protect electronic devices and humans from electromagnetic radiation. The construction of three-dimensional (3D) conductive networks is crucial to realize the excellent electromagnetic shielding performance of polymer-based aerogels. However, it is difficult to realize the interconnection of different conductive fillers in the polymer matrix, which limits the further improvement of their performance. Herein, 3D ordered hierarchical porous Fe3O4-decorated carbon nanotube (Fe3O4@CNT)/MXene/cross-linked aramid nanofiber (c-ANF)/polyimide (PI) aerogels were prepared via a unidirectional freezing strategy. Benefiting from the magnetic loss effect of Fe3O4 magnetic nanoparticles, the conductive and dielectric loss effects of CNTs, and the multiple reflections induced by the 3D ordered hierarchical porous structure, the Fe3O4@CNTs/MXene/c-ANFs/PI (FMCP) aerogels with the same contents of 8 wt % of Fe3O4@CNTs and MXene exhibit a high absolute EMI shielding effectiveness (SE) of up to 67.42 dB and a microwave reflection (SER) of 0.60 dB. More importantly, the phase transition of a small amount of MXene to TiO2 optimizes the impedance matching and transmission and then improves the microwave absorption. The FMCP aerogel has an outstanding normalized surface specific SE (SSE/t) which is up to 62,654 dB cm2·g-1. Meantime, the FMCP aerogels also show super-elasticity and could maintain 91.72% of the maximum stress after 1000 cycles of compression release under a fixed deformation of 60%.
RESUMO
Electrochemical oxygen evolution reaction (OER) always plays an important role in many electrochemical energy storage and conversion systems. Owing to the slow kinetics mainly brought from multiple proton-coupled electron transfer steps, the design and exploit low-cost, highly active, durable OER electrocatalysts are of significant importance. Although the black phosphorus (BP) shows good electrocatalytic OER performance, it still faces the problems of poor intrinsic activity and low stability due to its instability under ambient conditions. The NiFe-LDH was assembled onto the surfaces of exfoliated BP (EBP) nanoflakes to realize the interfacial coupling between them, achieving an effective improvement in electrocatalytic activity and stability. Benefitting from the interfacial P-O bonding, the NiFe-LDH@EBP hybrid shows high OER activity with a low overpotential of â¼240 mV@10 mA cm-2 toward OER under alkaline conditions, as well as the good stability. Density functional theory (DFT) calculations proved that the interface-coupling of NiFe-LDH on BP promotes charge transfer kinetics and balances the adsorption/desorption of reaction intermediates, ultimately imparting excellent OER electrocatalytic activity.
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The current research on the CO2RR process mainly focuses on the high selectivity of a single product and the material selectivity in the path process [1],[2] Guo et al ., 2019. There are relatively few studies on changes and causes. In this work, TiO2/TiO formed by in-situ oxidation was used as a photocatalyst for CO2 reduction. The structure of this semiconductor/metal-like heterojunction makes the internal electric field appear in the catalyst, which greatly improves the activity of the photocatalytic reaction. During the test, it was found that the hydrogenation product gradually appeared in the reaction product due to the appearance of TiO2. In the absence of a sacrificial agent, the catalyst exhibited a high HCOOH selectivity and obtained a considerable yield of 46.37 µmol g-1h-1. After adding the sacrificial agent triethanolamine (TEOA), TiO2/TiO showed good CO production ability. As the reaction progressed, CH4 was gradually produced. DFT calculations confirmed that the structure of the heterojunction has lower workfunction for the CO2 hydrogenation option, and the energy band at the contact position is curved. The construction of this system has guiding significance for the construction of light-driven CO2 hydrogenation products in the future.
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Based on the strategy that electrocatalysts can be used as additives to improve the performance of photocatalysts, and the unique metalloid properties of tungsten nitride (WN), it can form a Schottky junction with the semiconductor at the heterogeneous interface to improve the photocatalytic performance of semiconductor catalysts. In this paper, WN with excellent electrical conductivity was selected as a new noble-metal-free co-catalyst to improve the photoreduction hydrogen (H2) evolution performance of CdS nanoparticles (NPs). Firstly, WN nanosheets were prepared by sol-gel method; then, a novel and noble-metal-free heterojunction photocatalyst, which is CdS NPs deposited on the surface of WN, was successfully fabricated via one-pot solvothermal method. Under visible light irradiation, the H2 production rate of the WN/CdS composite catalyst is 24.13 mmol/g/h, which is 9.28 times that of pure CdS NPs. The observably boosted H2 generation activity could be ascribed to the broadened visible-light absorption and intimate interfacial contact between CdS NPs and WN engenders Schottky junction. This study provides a novel and cost-effective approach for designing efficient noble-metal-free photocatalysts and improving H2 evolution activity of CdS under visible-light-driven photocatalytic water splitting.
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Commercially, lithium metal batteries are still limited by the growth of lithium dendrites and excessive consumption of the electrolyte. A stable multifunctional solid electrolyte interface is the development strategy of lithium metal batteries in the future. However, most of the artificial solid electrolyte interphases (SEIs) cannot meet the original intention of multifunctional design and cannot form an SEI film with a high conductivity and low nucleation potential. In this work, we report a universal and simple method of adding multifunctional fluorosulfonate to a commercial electrolyte, so increasing the inorganic LiF in the SEI. In addition, the imidazole ring in the fluorosulfonate combines with the alkyl group in the electrolyte to form a flexible interface layer, which inhibits the growth of lithium dendrites and makes lithium deposition more uniform, thereby realizing a stable fast charge cycle. With an ultralow capacity of 2 mAh/cm2 deposited, the symmetrical battery can be deposited stably for nearly 300 h at a high current density of 20 mA/cm2. The capacity retention rate of the Li-LiFePO4 (LFP) full cell was still at 90.6% after 1000 cycles at 5 C. Even with 5 C high-rate fast charging, the capacity was maintained at 76.56% after 200 cycles, which is four times that of commercial electrolytes. This simple addition strategy gives insights into the practical application of the new electrolyte and provides a new idea for the construction of a stable SEI for commercial lithium metal batteries.
RESUMO
Plant-derived antimicrobial agents have adequate antimicrobial effects on food-borne pathogens, which can be used as food preservatives. The purpose of this study was to evaluate the antibacterial mechanism of chlorogenic acid (CA) against Yersinia enterocolitica and Enterobacter sakazakii. The minimum inhibitory concentration (MIC) of CA was determined by employing the broth microdilution method. Then, the cell function and morphological changes of Y. enterocolitica and E. sakazakii treated with CA were characterized. Finally, the growth inhibition models of Y. enterocolitica in raw pork and E. sakazakii in skim milk were constructed through the response surface methodology. The results demonstrated that CA has a satisfactory inhibitory effect against Y. enterocolitica and E. sakazakii with a MIC of 2.5 mg/mL. In addition, CA inhibited the growth of Y. enterocolitica and E. sakazakii via cell membrane damage, such as depolarization of the cell membrane, reduction in intracellular adenosine triphosphate (ATP) and pH levels, and destruction of cell morphology. Moreover, CA reduced two log cycles of Y. enterocolitica in raw pork and E. sakazakii in skim milk at a certain temperature. According to the corresponding findings, CA has the potential to be developed as an effective preservative to control Y. enterocolitica and E. sakazakii-associated foodborne diseases.
Assuntos
Antibacterianos/farmacologia , Ácido Clorogênico/farmacologia , Cronobacter sakazakii/efeitos dos fármacos , Conservação de Alimentos , Yersinia enterocolitica/efeitos dos fármacos , Animais , Antibacterianos/química , Membrana Celular/efeitos dos fármacos , Ácido Clorogênico/química , Cronobacter sakazakii/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Leite/efeitos dos fármacos , Leite/microbiologia , Carne de Porco/microbiologia , Yersinia enterocolitica/crescimento & desenvolvimentoRESUMO
Phosphorous oxide (PxOy)-incorporated carbon nanotubes (PCNTs) and nitric acid treated carbon nanotubes (OCNTs) are first synthesized, then phosphorous modified palladium nanoparticles (Pd-P NPs) supported on PCNTs (Pd-P/PCNTs) and OCNTs (Pd-P/OCNTs) are synthesized and employed as electrocatalysts in a methanol oxidation reaction. Pd-P/PCNTs show enhanced electrocatalytic activity and stability in comparison to Pd-P/OCNTs. Combining surface analysis and electrochemical performance, PxOy incorporated into CNTs could create anchoring sites for Pd ions and P precursors, which could facilitate the synthesis of Pd-P NPs in an aqueous solution containing Pd ions and sodium hypophosphite serving as a reducing agent and a P source. The electronic modification of embedded Pd-P NPs on PxOy-incorporated CNTs accounts for the enhanced electrochemical performance of Pd-P/PCNTs.