查看更多>>摘要：Photocatalytic technology has great potential in environmental remediation due to the advantages of being green and cost-effective. Still, drawbacks such as high carrier recombination and poor photo-utilization efficiency hinder its large-scale application. Fortunately, defect modulation has been proven to be an effective tactic for solving the above problems. In this study, cationic vacancies were introduced in layered bismuth molybdate (Bi2MoO6) by controlled alkali etching. The results showed that the optimized Mo vacancy concentration increased the degradation efficiency of tetracycline hydrochloride to 82 % with a kinetic constant 2.4 times higher than that of bulk Bi2MoO6, which is superior to most reported Bi-based catalysts. In-situ KPFM, PL, and photoelectrochemical measurements confirm that the boosted activity is attributed to photo-excited charge carriers' excellent separation and migration ability. This work supplies a feasible strategy to enhance the photocatalytic performance of Bi2MoO6 and provides a novel insight into designing other advanced materials for photocatalytic applications.
Muzhanje, Allan T.Hassan, Mohsen A.Gepreel, Mohammed H.Ookawara, Shinichi...
1.1-1.9页
查看更多>>摘要：Herein, the preparation and characterization of homogeneous nanoparticle enhanced phase change material (PCM) is presented. Sp07/sp11 PCMs suitable for winter climate conditions are mixed with 0.5-5.0 wt. % of CuO/Al2O3 nanoparticles (NPs). Results indicate that stable PCM-nanoparticles composites are produced without altering the base material's chemical structure and crystalline nature. The produced composites do not sediment even after multiple thermal cycles. The materials have slightly increased densities and improved viscosity. The complete melting time reduces by similar to 34.8 % for 5.0 wt. %CuOsp07 and similar to 20.7 % for 5.0 wt. %Al(2)O(3)sp11 compared to base PCMs. Using 5.0 wt. % CuO nanoparticles with sp11 improves its pH by 0.34. A 0.25 wt. %CuOsp11 sample's latent heat is deteriorated by similar to 7.3 % when composition rises to 5.0 wt. %CuO.
查看更多>>摘要：Polycrystalline In1_xGaxAs thin films are promising for high-performance electronics on versatile substrates, including transistors, solar cells, optical communication devices, and infrared sensors. This study examines the effects of composition, deposition temperature, and impurity doping on the grain size, crystal orientation, nanostructure, and electrical properties of In1_xGaxAs layers, utilizing various evaluation methods with machine learning. The results demonstrate that the composition and deposition temperature significantly influence the crystallinity and crystal orientations. Higher In compositions and deposition temperatures yield In1_xGaxAs with enhanced crystallinity. The undoped samples exhibit n-type conduction, which is likely attributable to antisite defects. Increasing the In content and deposition temperature increases the electron concentration and mobility up to 3 x 1018 cm_ 3 and 310 cm2 V_1s_1, respectively. Sn is an effective n-type dopant, facilitating the control of electron concentration within the range of 1017-1019 cm_ 3. These findings offer valuable insights into the application of In1_xGaxAs in high-performance electronic devices.
查看更多>>摘要：In this study, PVA/TA hydrogel films were fabricated using the solution casting method. To enhance mechanical properties and antibacterial activity, citric acid was employed as a green crosslinking agent, and TiO2 nanoparticles were incorporated. SEM images showed the formation of a porous structure with interconnected pores, which facilitated water and steam penetration. FTIR studies confirmed the interaction between PVA, CA, and TA. The addition of TiO2 significantly improved the water vapor transmission rate. Increasing the amount of CA and TA led to increased crosslinking, resulting in reduced swelling, degradation and hydrophilicity. The results of mechanical investigations showed an increase in the tensile strength with increasing CA and TA content and an increase in stiffness with increasing CA and decreasing TA content. Furthermore, the addition of TiO2 up to 1 wt % further improved the mechanical properties. These findings indicate the potential of PVA/TA/TiO2 hydrogel for biomedical applications, especially in wound dressings.
查看更多>>摘要：Bio-based benzoxazine (CBPA-Bz) resin was synthesized using card-bisphenol derived from cardanol, and aniline with paraformaldehyde through Mannich condensation followed by thermal polymerization to obtain polybenzoxazine (CBPA-PBz). Free hydroxyl groups of the polybenzoxazine matrix developed on polymerization have been modified in the form of ester via esterification with dodecenyl succinic anhydride (DSA) at high temperature through in situ reaction. The non-activated bio-carbon (Cna) and acid-activated bio-carbon (Caa) were derived from Phragmites karka (p.karka). Different weight percentages of bio-carbons reinforced hybrid CBPA-DSA-PBz-Cna/aa polybenzoxazine composites were prepared, and studied their dielectric, thermal, and waterrepellent properties. FTIR and 1H NMR spectra were used to ascertain the molecular structure of the benzoxazine monomer and polymer composites. The hybrid CBPA-DSA-PBz and its composites exhibit higher values of water contact angle (WCA) between 141o and 165o infer their (super) hydrophobic behaviour compared to its pristine CBPA-PBz matrix (WCA = 140o). The hydrophobic property of the developed polybenzoxazine (CBPA-DSA-PBz) and its composites (CBPA-DSA-PBz-Cna/aa1-10) could provide an authentic dielectric constant and dielectric loss values, because of preventing the effect of moisture on dielectric measurement. The CBPA-DSA-PBz-Cna10 and CBPA-DSA-PBz-Caa10 hybrid composites show high values of dielectric constant, 6.97 and 7.55, respectively.
El-Hout, Soliman I.Abdel-Haleem, Fatehy M.Mohamed, Reda M.Algethami, Faisal K....
1.1-1.10页
查看更多>>摘要：Water pollution is one of the more significant worldwide problems; notably, water pollution caused by harmful herbicides like Atrazine negatively influences the health of individuals and the ecosystem. The rendering of conventional methods is ineffective for treating antibiotic-laden wastewater. Currently, photocatalytic technology has emerged as a promising solution for degrading low-concentration, water-soluble herbicide residues through deep mineralization. Here, we showed a hydrothermally-prepared BaTiO3 coupled with different contents of narrow-bandgap silver oxide (Ag2O) nanocrystals. The synthesized materials underwent advanced characterization, which verified the successful formation of nanostructured Ag2O-BaTiO3. These heterostructures exhibited high specific surface areas (80-120 m(2)/g) while their fundamental structural and surface integrity remained intact. The photocatalytic performance of the prepared materials was further assessed for atrazine mineralization and degradation efficiency in aqueous solutions under visible-light irradiation. Optimal doping with trace concentrations of Ag2O significantly improved light absorption, charge carrier mobility, and separation efficiency while reducing the material's bandgap to 2.66 eV. The composite containing just 3wt% Ag2O achieved complete photoelimination of atrazine under visible light within 1 hour, outperforming pure BaTiO3 (8.0 +/- 0.5)%. Notably, the 3wt% Ag2O-BaTiO3 heterostructures exhibited a significantly enhanced kinetic rate constant of 4.28x10(-2) min(-1), similar to 32.7-fold compared to pure BaTiO3. Additionally, the heterostructures demonstrated exceptional recyclability in repeated atrazine photodegradation cycles, highlighting their practical applicability. A plausible mechanism for charge carrier separation within mesoporous Ag2O-BaTiO3 heterostructures was proposed, elucidating their enhanced photocatalytic activity. This study concludes that photocatalysts based on perovskite titanates will likely be utilized for water treatment purposes.
查看更多>>摘要：The mechanical quality factor (Qm) is a key parameter in the applications of piezoelectric ceramics. For force sensors and acoustic transducers, low Qm allows a broadened frequency range for signal reception. Currently, the most popular low-Qm materials are lead-based ferroelectric ceramics, such as PbNb2O6. However, restrictive regulations on Pb-containing components have prompted the search for alternative lead-free piezoelectrics. Some studies on low-Qm lead-free ceramics have been reported, but without clarifying its origin. Here, lead-free piezoceramics with a nominal composition K0.475Na0.475Bi0.025Ag0.025Nb0.95Hf0.05O3 (KNN-BAH) were developed by a partial substitution of K and Na at A-sites with Bi and Ag, and the Nb at B-sites with Hf in K0.50Na0.50NbO3 (KNN). The KNN-BAH ceramics sintered at 1080 degrees C and 1120 degrees C showed Qm values of about 27.2 and 57.1, respectively, which are among the lowest values reported for lead-free piezoelectric ceramics. The ultralow Qm is attributed to the bi-phasic structure and enhanced domain wall motion.
查看更多>>摘要：Manganese dioxide (MnO2) has become a great potential cathode material for aqueous zinc-ion batteries (AZIBs), owing to its advantages such as high theoretical capacity, moderate potential window, low price and abundant reserves. However, the inner poor electrical conductivity and sluggish reaction kinetics of MnO2 can lead to the irreversible phase transition and capacity decay, limiting its further application. Herein, we developed a simple co-precipitation method to construct reduced graphene oxide modified MnO2 nanoflowers with hexagonal structure (MnO2/RGO). Ascribed to the synergetic effects of MnO2 nanoflowers with high theoretical capacity and RGO with high conductivity and stability, the MnO2/RGO composite delivers excellent zinc-ion storage performance with superior cycling stability (222.0 mAh g- 1 at 0.2 A g- 1 after 200 cycles and 72.6 mAh g- 1 at 2.0 A g- 1 after 3000 cycles), fast charge transfer and ion diffusion kinetics.
查看更多>>摘要：A cobalt-based metal-organic framework, [Co(Cei)]n(Co-MOF), and its silver-doped derivatives (Ag@Co-MOF-n, where n = 1-3) were synthesized and systematically characterized using XPS, PXRD, SEM, elemental mapping, and FT-IR techniques. Among the derivatives, Ag@Co-MOF-2 exhibited superior photoluminescent sensing capabilities for the herbicides chlorimuron ethyl (CLOV) and glyphosate (GYP), with LOD values of 0.580 ppm and 0.067 ppm, respectively. Under visible light, the photocatalytic degradation efficiency of Ag@Co-MOF-2 for GYP reached 88.07%, significantly outperforming the pristine Co-MOF (37.38%). Furthermore, in supercapacitor applications, Ag@Co-MOF-2 demonstrated an enhanced specific capacitance of 582.0 F g-1 with 74.62% retention after 10,000 cycles, compared to 294 F g-1 and 69.98% retention for Co-MOF. These findings underscore the multifunctional enhancements imparted by silver doping, establishing Ag@Co-MOF-2 material as a promising material for energy storage, advanced sensing, and environmental remediation applications.
查看更多>>摘要：Fe3O4 is an important electromagnetic wave absorption material with both dielectric and magnetic losses. However, the synergistic effect of different particle sizes of Fe3O4 on the absorption performance is less reported, not to mention the effect of coating dielectric layer on Fe3O4. In this paper, the minimum reflection loss of-50.74 dB is obtained for the mixture of Fe3O4-5.5 and the effective bandwidth reaches 4.38 GHz. Meanwhile, the effective bandwidth and reflection loss values can be further improved by covering dielectric TiO2 layer. The effective bandwidth of Fe3O4-5.5@TiO2 increases to 5.36 GHz and the minimum reflection loss lowers to-51.1 dB. The enhanced performance is not only ascribed to space charge polarization and dipole polarization caused by oxygen vacancies in TiO2, but also polarization interface caused by multi-polarization as evidenced from experimental and finite element method simulation. This paper provides a new strategy for preparation of microwave absorption material with enhanced performance.
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Elsevier