Two semiconductors (Cu2O and TiO2) were chosen for the photocatalytic reduction of bicarbonate to formate in order to perform a systematic study on the effect of six different hole (h+) scavengers. The six h+ scavengers selected for the study include glycerol, ethylene glycol, 2-propanol, sodium sulfite, triethanolamine, and ethylenediaminetetraacetic acid. Glycerol proved to be the most efficient h+ scavenger, and TiO2 in glycerol showed the highest quantum efficiency of 5.04 ± 0.3%. This finding bodes well as a sustainable one because glycerol is environmentally benign, a low-cost material, and is derived from plants, as opposed to petroleum sources like 2-propanol or ethylene glycol.

Porous TiAl3 intermetallics were synthesized by the thermal explosion (TE) reaction from TiH2–75 at.% Al elemental powders combining with carbamide as the space holder. The results showed that the space holder particles were removed completely by dissolving in water before sintering and the violent exothermic reaction occurred from the temperature of 672–1193 °C within a few seconds. After TE, TiAl3 was the dominant phase in sintered products and the open porosity of 60.8% was obtained without space holder, while the porosity considerably increased to 81.4% with the addition of 60 vol% carbamide particles. The pore-forming mechanism can be concluded as follows: the sphere large pores replicated from carbamide particles and the small pores generated by the TE reaction. Moreover, porous TiAl3 intermetallics possess the excellent oxidation resistance at 650 °C in air, which enabled them good candidate materials for improving the service life and the accuracy of filtration under special conditions.

This study compared the effect of gelatin- and chitosan-based scaffolds on osteoblast biomineralization. These scaffolds have been modified using methacrylate and laponite nanosilicates to improve their mechanical strength and support osteoblast function. Scaffold materials were prepared to have the same compressive strength (14–15 MPa) such that differences in cell response would be isolated to differences in biopolymer chemistry. The materials were tested for rheological properties to optimize the bio-ink for successful 3D printing using a robocast-assisted deposition system. Osteoblasts were cultured on the surface of 3D-printed methacrylated chitosan-laponite (MAC-Lp), methacrylated gelatin-laponite (MAG-Lp), MAC, and MAG scaffolds. MAC-Lp scaffolds showed increased cell viability, cell growth, and biomineral formation as compared to MAG-Lp scaffolds. FTIR results showed the presence of higher biomineral phosphate and extracellular matrix (ECM) collagen-like amide formation on MAC-Lp scaffolds as compared to MAG-Lp scaffolds. MAC-Lp scaffolds showed increased density of ECM-like tissue from SEM analysis, stained mineral nodules from Alizarin staining, and the existence of Ca–P species evident by X-ray absorbance near edge structure analysis. In conclusion, MAC-Lp scaffolds enhanced osteoblast growth and biomineral formation as compared to MAG-Lp scaffolds.

Polyurethane/cellulose composites were synthesized from castor-oil-derived polyols and isophorone diisocyanate using dibutyltin dilaurate (DBTDL) as the catalyst. Materials were obtained by adding 2% cellulose in the form of either microcrystals (20 μm) or nanocrystals obtained by acid hydrolysis. The aim was to assess the effects of filler particle size and the use of a catalyst on the physicochemical properties and biological response of these composites. The addition of the catalyst was found to be essential to prevent filler aggregations and to enhance the tensile strength and elongation at break. The cellulose particle size influenced the composite properties, as its nanocrystals heighten hydrogen bond interactions between the filler surface and polyurethane domains, improving resistance to hydrolytic degradation. All hybrids retained cell viability, and the addition of DBTDL did not impair their biocompatibility. The samples were prone to calcification, which suggests that they could find application in the development of bioactive materials.

Three photosensitizers containing zinc(II) porphyrin, ruthenium(II) dipyridine, and their combined porphyrin–polypyridyl metal complexes were used to modify TiO2 nanotubes that were obtained through the hydrothermal method to get inorganic–organic nanocomposite photocatalysts. The photosensitizer with distinctive structure can expand the photoresponse range of TiO2 toward the range of visible light, and the complexes with large conjugated π-electron systems are beneficial for improving the separation of photoelectrons from vacancies, effectively extending the life of excited electrons and thus enhancing the photocatalytic efficiency, thus establishing a favorable foundation for an efficient photocatalysis reaction. The photocatalytic reduction of CO2 aqueous solution into methanol was used to evaluate the photocatalytic effect of sensitized samples. All the photosensitized catalysts exhibited superior selectivity in liquid products during this process and methanol was the only liquid product in the system. The ZnPyP–RuBiPy sensitized TiO2 nanotubes showed the best photocatalytic effect. A possible mechanism for the photoreduction was also proposed in this paper.

We report the fabrication and testing of MnO2–carbon nanotube (NT) electrodes for supercapacitors (SCap) with high active mass (AM). Cetylpyridinium chloride surfactant was used as a capping agent for synthesis and a phase transfer agent for the liquid–liquid extraction. Water immiscible solvent, n-butanol, was used as a receiving and reducing medium for the synthesis of MnO2 from cetylpyridinium permanganate. Improved co-dispersion and nanoscale mixing of MnO2 and NT enabled the fabrication of advanced electrodes with mass loading of 42–61 mg/cm2, ratio of AM to current collector mass of 0.63–0.91, which showed the highest capacitance of 8.95 F/cm2.

There is an increasing interest in the generation of well-defined nanoparticles (NPs) not only because of their size-related particular properties, but also because they are promising building blocks for more complex materials in nanotechnology.

Here, we will shortly introduce the gas-phase synthesis technology that has evolved rapidly in the last years and allows the fabrication of complex NPs with controllable and tuneable chemical composition and structure while keeping very good control over the size distribution. We will also address some limitations of the technology (stability over time, production yield, etc.) and discuss possible solutions.

We have studied by electron microscopy and x-ray diffraction techniques the amorphous-to-crystalline phase transition which occurs during annealing of a highly Ge-rich and N-doped amorphous GeSbTe material. The crystallization onset occurs at 380 °C with the diffusion and segregation of Ge followed by the formation of Ge nanocrystals. The GeSbTe face-centered cubic (FCC) crystalline phase only appears at 400 °C. Phase separation occurs because the Ge concentration is well above what can be accommodated by the Ge2Sb2Te5 lattice. The possible formation of a two-phase material should be considered in order to simulate device characteristics and optimize material composition for electronic memory applications.

Vertically aligned nitrogen-doped nanocrystalline diamond nanorods are fabricated from nitrogen-doped nanocrystalline diamond films using reactive ion etching in oxygen plasma. These nanorods show enhanced thermionic electron emission (TEE) characteristics, viz., a high current density of 12.0 mA/cm2 and a work function value of 4.5 eV with an applied voltage of 3 V at 923 K. The enhanced TEE characteristics of these nanorods are ascribed to the induction of nanographitic phases at the grain boundaries and the field penetration effect through the local field enhancement from nanorods owing to a high aspect ratio and an excellent field enhancement factor.

The thermal conductivities (κ) of bulk and thin-film α-Al2O3 are calculated from first principles using both the local density approximation (LDA) and the generalized gradient approximation (GGA) to exchange and correlation. The room temperature single-crystal LDA value ~39 W/m K agrees well with the experimental values ~35–39 W/m K, whereas the GGA values are much smaller ~26 W/m K. Throughout the temperature range, LDA is found to slightly overestimate κ, whereas GGA strongly underestimates it. We calculate the κ of crystalline α-Al2O3 thin films and observe a maximum of 79% reduction for 10 nm thickness.

The concept of high-entropy alloys has been extended to ceramics, polymers, and composites. “High-entropy materials (HEMs)” are named to cover all these materials. Recently, HEMs has become a new emerging field through the collective efforts of many researchers. Basically, high mixing entropy can enhance the formation of solution-type phases for alloys, ceramics, and composites at high temperatures, and in general leads to simpler microstructure. Large degrees of freedom in composition design as well as process design have been found to provide a wide range of microstructure and properties for applications. There are many opportunities for HEMs to overcome the bottlenecks of conventional materials. In this article, several possible breakthrough applications are pointed out and emphasized for turbine blades, thermal spray bond coatings, high-temperature molds and dies, sintered carbides for cutting tools, hard coatings for cutting tools, hardfacings, and radiation-damage resistant materials. In addition, more possible breakthrough examples are briefly described.

This review aims to consolidate scarce literature on the use of modern nanomechanical testing technique like instrumented nanoindentation in the field of archaeometry materials research. The review showcase on how can the nanoindentation tests provide valuable data about mechanical properties which, in turn, relate to the evolution of ancient biomaterials as well as human history and production methods. This is particularly useful when the testing is limited by confined volumes and small material samples (since the contact size is in the order of few microns). As an emerging novel application, some special considerations are warranted for characterization of archaeometry materials. In this review, potential research areas relating to how nanoindentation is expected to benefit and help improve existing practices in archaeometry are identified. It is expected that these insights will raise awareness for use of nanoindentation at various world heritage sites as well as various museums.

The current review outlines the size-dependent plastic behavior of high-entropy alloys (HEAs) and the underlying deformation mechanisms. Particular focus is laid upon the influence of microstructural design on the small-scale deformation characteristics. The role of defect types as carriers of plasticity is appraised and correlated with the frequently observed mechanical behavior peculiar to the breed of HEAs. Deformation response is classified on the basis of mechanical testing techniques probing intrinsic (nanoindentation techniques) as well as extrinsic size (micro/nanopillar compression) effects. The mechanisms of incipient plasticity and serrated flow behavior in HEAs are discussed. Furthermore, the role of interfaces between crystallographically dissimilar lattices on small-scale deformation behavior in these alloys is assessed. The article provides a clear overview of the existing HEA research in this avenue as well as the critical knowledge gaps that need to be addressed.

With the aim of understanding the excitation energy transfer mechanism in natural photosynthetic membranes, light-harvesting (LH)2 and LH1-reaction center, which are pigment-protein complexes separated from Rhodobacter sphaeroides, were aligned on a planar electrode surface in stripe patterns at 5 µm intervals. Observation of the absorption spectrum and fluorescence microphotographs revealed selective immobilization and conservation of the pigments. Photocurrent signals were obtained when the electrode was illuminated at either 880 or 800 nm. The fabricated structure was confirmed to function as a natural photosynthetic membrane with the highest photocurrent signal being obtained when using a co-immobilized substrate under excitation at 800 nm.

The basic principle of high-entropy alloys (HEAs) is that high mixing entropies of solid-solution phases enhance the phase stability, which renders us a new strategy on alloy design. The current research of HEAs mostly emphasizes mechanical behavior at room and higher temperatures. Relatively fewer papers are focused on low-temperature behaviors, below room temperature. However, based on the published papers, we can find that the low-temperature properties of HEAs are generally excellent. The great potential for cryogenic applications could be expected on HEAs. In this article, we summarized and discussed the mechanical behaviors and deformation mechanisms, as well as stacking-fault energies, of HEAs at low temperatures. The comparison of low-temperature properties of HEAs and conventional alloys will be provided. Future research directions will be suggested at the end.

We analyze charge density transfer from water to solvated transition metal (TM) ions in different formal oxidation states (FOSs) in aqueous solution by first principles and relate the degree of stabilization of the solvated cations to the charge donation from the water ligands. We find remarkable charge stability on the metal center regardless of FOSs. This effect is similar to what has previously been shown for charges on TM cations in inorganic crystals. This ligand-to-metal charge transfer results in softening of the ligand O–H bonds, which can be used to explain the formation of higher-FOS transition metalates and oxycations.

A thermo-pH sensitive graft copolymer was successfully obtained by grafting 4-vinylpyridine and N-vinylcaprolactam onto silicone rubber ((SR-g-4VP)-g-NVCL)) in two-step using ionizing radiation as an initiator. Factors such as dose and monomer concentration remarkably affected the grafting yield. Surface grafted films were well characterized by means of infrared-attenuated total reflection, carbon-13 nuclear magnetic resonance, thermogravimetric analysis, and mechanical properties were also studied. Scanning electron microscopy demonstrated that the grafting was superficial; mechanical studies demonstrated that grafting caused loss elongation of SR films. The grafted films showed a critical pH close to physiological pH and a critical temperature (lower critical solution temperature) about 35 °C, therefore, this material presents potential biomedical applications as drug delivery.

We show that the optical response of ultrathin metallic films of finite lateral size and thickness can feature peculiar magneto-optical effects resulting from the spatial confinement of the electron motion. In particular, the frequency dependence of the magnetic permeability of the film exhibits a sharp resonance structure shifting to the red as the film aspect ratio increases. The films can also be negatively refractive in the IR frequency range under proper tuning. We show that these magneto-optical properties can be controlled by adjusting the film chemical composition, plasmonic material quality, the aspect ratio, and the surroundings of the film.