Frontiers of Materials Science最新文献

In this study, a novel diethylene triamine penta(methylene phosphonic acid) (DTPMPA)- and graphene oxide (GO)-modified superhydrophobic anodized aluminum (DGSAA) coating was fabricated. The obtained coatings were characterized by scan electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and Raman analysis. After immersion in the supersaturated CaCO₃ solution for 240 h, the scaling mass of the DGSAA coating is only 50% of that of the SAA coating. The excellent anti-scaling performance of the DGSAA coating comes from three barriers of the air layer, the DTPMPA:Ca²⁺ chelate, and the lamellar GO, as well as the further active anti-scaling of DTPMPA:Ca²⁺ at the coating-solution interface. DTPMPA and GO at the surface of the DGSAA coating exhibit an insertion structure. In the electrochemical impedance spectroscopy measurement, the impedance modulus of the DGSAA coating is three orders-of-magnitude higher than that of the anodized aluminum. The synergistic effect of DTPMPA stored in the porous structure of anodized aluminum and the barrier protection of superhydrophobicity and GO contributes to the excellent comprehensive performance of the DGSAA coating. This research provides a new perspective for designing anti-scaling and anti-corrosion superhydrophobic bi-functional coatings.

Sn-based materials are considered as a kind of potential anode materials for lithium-ion batteries (LIBs) owing to their high theoretical capacity. However, their use is limited by large volume expansion deriving from the lithiation/delithiation process. In this work, amorphous Sn modified nitrogen-doped porous carbon nanosheets (ASn-NPCNs) are obtained. The synergistic effect of amorphous Sn and high edge-nitrogen-doped level porous carbon nanosheets provides ASn-NPCNs with multiple advantages containing abundant defect sites, high specific surface area (214.9 m²·g⁻¹), and rich hierarchical pores, which can promote the lithium-ion storage. Serving as the LIB anode, the as-prepared ASn-NPCNs-750 electrode exhibits an ultrahigh capacity of 1643 mAh·g⁻¹ at 0.1 A·g⁻¹, ultrafast rate performance of 490 mAh·g⁻¹ at 10 A·g⁻¹, and superior long-term cycling performance of 988 mAh·g⁻¹ at 1 A·g⁻¹ after 2000 cycles with a capacity retention of 98.9%. Furthermore, the in-depth electrochemical kinetic test confirms that the ultrahigh-capacity and fast-charging performance of the ASn-NPCNs-750 electrode is ascribed to the rapid capacitive mechanism. These impressive results indicate that ASn-NPCNs-750 can be a potential anode material for high-capacity and fast-charging LIBs.

In order to provide a biomimetic natural extracellular matrix microenvironment with excellent mechanical capacity for tissue regeneration, a novel porous hybrid glycidyl methacrylate-modified silk fibroin/poly(L-lactic acid-ε-caprolactone)-polyethylene glycol diacrylate (SFMA/P(LLA-CL)-PEGDA) hybrid three-dimensional (3D) nanofibrous scaffolds was successfully fabricated through the combination of 3D nanofibrous platforms and divinyl PEGDA based photocrosslinking, and then further improved water resistance by ethanol vapor post-treatment. Scanning electron microscopy and micro-computed tomography results demonstrated significant PEGDA hydrogel-like matrices bonded nanofibers, which formed a 3D structure similar to that of “steel bar (nanofibers)–cement (PEGDA)”, with proper pore size, high porosity, and high pore connectivity density. Meanwhile, the hybrid 3D nanofibrous scaffolds showed outstanding swelling properties as well as improved compressive and tensile properties. Furthermore, these hybrid 3D nanofibrous scaffolds could provide a biocompatible microenvironment, capable of inducing the material–cell hybrid and regulating human umbilical vein endothelial cells proliferation. They thus present significant potential in tissue regeneration.

Sintering resistant noble metal nanoparticles are critical to the development of advanced catalysts with high activity and stability. Herein, we reported the construction of highly dispersed Pd nanoparticles loaded at the inner wall of ZrO₂ hollow spheres (Pd@HS-ZrO₂), which shows improved activity and thermal stability over references in the Pd-ZrO₂ (catalyst-support) system. Even after 800 °C high temperature calcination, the Pd nanoparticles and ZrO₂ hollow spheres did not undergo morphological changes. The Pd@HS-ZrO₂ manifests batter catalytic activity and thermal stability than the counterpart Pd/ZrO₂ catalysts. In comparison to Pd/ZrO₂-800, Pd@ZrO₂-800 exhibits a 25°C reduction in the temperature required for complete conversion of CO. The enhanced catalytic activity and thermal stability of Pd@HS-ZrO₂ can be attributed to the nanoconfinement effect offered by the 10 nm wall thickness of the ZrO₂ hollow spheres, which suppresses the coarsening of the Pd nanoparticles (active center for catalysis).

As a new type of luminescent material, carbon dots (CDs) have attracted increased attention for their superior optical properties in recent years. However, solid-state fluorescent CDs, especially with red emission, are still a major challenge. Here, CDs with solid-state red emission were synthesized by co-doping of N and B using the one-step microwave method. The CD powder exhibits excitation-independent solid-state red fluorescence without any dispersion matrices, with optimum solid-state fluorescence wavelength of 623 nm. The hydrogen bonding interaction in CDs is helpful for solid-state fluorescence of CDs. The _IG/_ID value of CDs reaches up to 3.49, suggesting their very high graphitization degree, which is responsible for their red emission. In addition, CDs show the concentration-induced multicolor emission, which is attributed to the decreased energy gap in the high concentrated CD solution. To exploit their concentration-dependent emission, CDs with changing ratio in matrices are applied as a color-converting layer on ultraviolet chip to fabricate multicolor light-emitting diodes with light coordinates of (0.33, 0.38), (0.41, 0.48), (0.49, 0.44), and (0.67, 0.33), which belong to green, yellow, orange, and red light, respectively.

Developing high-activity and low-cost catalysts is the key to eliminate the limitation of sluggish anodic oxygen evolution reaction (OER) during electrocatalytic overall water splitting. Herein, Ni–Fe/black phosphorous (BP) composites are synthesized using a simple three-electrode system, where exfoliation of bulky BP and synthesis of NiFe composites are simultaneously achieved. Under light illumination, the optimized Ni–Fe/BP composite exhibits excellent photoelectrocatalytic OER performance (e.g., the overpotential is 58 mV lower than a commercial RuO₂ electrocatalyst at a current density of 10 mA·cm⁻²). The electron transfer on this composite is proved to follow a Ni–BP–Fe pathway. The electronic structure of this Ni–Fe/BP composite is effectively regulated, leading to optimized adsorption strength of the intermediate OH* and improved intrinsic activity for the OER. Together with active sites on the support, this Ni–Fe/BP composite possesses abundant electrochemical active sites and a bug surface area for the OER. The introduction of light further accelerates the electrocatalytic OER. This work provides a novel and facile method to synthesize high-performance metal/BP composites as well as the approaches to reveal their OER mechanisms.

In the research for the safe and efficiently antibacterial cotton fabrics to minimize risk for human health, an organic–inorganic hybrid material of ZnO nanoparticles (NPs) and quaternary ammonium salt (QAS) was employed to modify cotton fabrics by a dipping–padding–drying method. The synergistic effects of ZnO NPs and QAS on the structure and antibacterial properties of cotton fabrics were studied in detail. Results displayed that the QAS and ZnO NPs were immobilized firmly in cotton fabric by the formation of chemical covalent bonds and silica gel structure. ZnO/QAS/cotton had a good inhibitory effect on the growth of E. coli and S. aureus, with superior antibacterial efficiency of >99.99%. ZnO/QAS/cotton preserved good mechanical property, water absorbability, and limpness. We also provided a detailed analysis of antibacterial mechanism for the hybrid materials. The contact mechanism and the Zn²⁺ release were considered as the main mechanisms for the ZnO/QAS/cotton, while the reactive oxygen species (ROS) generation only had a little contribution to the antibacterial activity. In short, the excellent integrated properties endowed the hybrid cotton fabrics as potential application in many fields, like healthcare, food packaging.

The catalytic conversion of biomass platform chemicals using abundant non-noble metal nanocatalysts is a challenging topic. Here, high-density cobalt oxide nanoparticles loaded on biomass-derived porous N-doped carbon (NC) was fabricated by a tandem hydrothermal pyrolysis and mild nitrate decomposition process, which is a green and cheap preparation method. The Co₃O₄ nanoparticles with the average size of 12 nm were uniformly distributed on the porous NC. The nanocomposites also possessed large surface area, high N content, good dispersibility in isopropanol, and furfural absorbability. Due to these characteristics, the novel cobalt nanocatalyst exhibited high catalytic activity for producing furfuryl alcohol, yielding 98.7% of the conversion and 97.1% of the selectivity at 160 °C for 6 h under 1 bar H₂. The control experiments implied that both direct hydrogenation and transfer hydrogenation pathways co-existed in the hydrogenation reaction. The excellent catalytic activity of Co₃O₄@NC was attributed to the cooperative effects of porous NC and Co₃O₄ nanoparticles. This approach provides a new idea to design effective high-density nonnoble metal oxide nanocatalysts for hydrogenation reactions, which can make full use of sustainable natural biomass.

Processing biomaterials into porous scaffolds for bone tissue engineering is a critical and a key step in defining and controlling their physicochemical, mechanical, and biological properties. Biomaterials such as polymers are commonly processed into porous scaffolds using conventional processing techniques, e.g., salt leaching. However, these traditional techniques have shown unavoidable limitations and several shortcomings. For instance, tissue-engineered porous scaffolds with a complex three-dimensional (3D) geometric architecture mimicking the complexity of the extracellular matrix of native tissues and with the ability to fit into irregular tissue defects cannot be produced using the conventional processing techniques. 3D printing has recently emerged as an advanced processing technology that enables the processing of biomaterials into 3D porous scaffolds with highly complex architectures and tunable shapes to precisely fit into irregular and complex tissue defects. 3D printing provides computer-based layer-by-layer additive manufacturing processes of highly precise and complex 3D structures with well-defined porosity and controlled mechanical properties in a highly reproducible manner. Furthermore, 3D printing technology provides an accurate patient-specific tissue defect model and enables the fabrication of a patient-specific tissue-engineered porous scaffold with pre-customized properties.

Despite more than a decade of study, there are still significant obstacles to overcome before graphene can be successfully produced on a large scale for commercial use. Chemical oxidation of graphite to produce graphene oxide (GO), followed by a subsequent reduction process to synthesize reduced graphene oxide (rGO), is considered the most practical method for mass production. Microorganisms, which are abundant in nature and inexpensive, are one of the potential green reductants for rGO synthesis. However, there is no recent review discussing the reported microbial reduction of GO in detail. To address this, we present a comprehensive review on the reduction of GO by a range of microorganisms and compared their efficacies and reaction conditions. Also, presented were the mechanisms by which microorganisms reduce GO. We also reviewed the recent advancements in using microbially reduced GO as the anode and cathode material in the microbial fuel cell (MFC) and algal biophotovoltaics (BPV), as well as the challenges and future directions in microbial fuel cell research.