Recent trends in the area of catalytic applications of metal–organic framework (MOF)-derived nanocarbons are covered. These highly porous nanostructures, convenient for the green chemistry processes, are generally formed by the direct carbonization of a variety of MOF, mainly MOF-5, ZIF-8, ZIF-67, UiO-66-NH2, MIL-101-NH2 at 700–1000 °C in argon or nitrogen flow. Differences between conventional porous carbons and MOF-derived carbons are in pore volumes, surface area, and presence of ad-atoms. The morphology of the MOF-derived nanocarbons can be adjustable with uniform dopant distribution. Resulting nanocarbons are widely applied in heterogeneous catalysis, photocatalysis and are very promising as electrocatalysts, having excellent performance in oxygen evolution reaction, oxygen reduction reaction, and hydrogen evolution reaction. Catalytic applications for environmental purposes are also discussed. Good catalytic performance is related with highly dispersed heteroatoms, density of catalytic active sites, controllable porosity, and high surface area. Opportunities for further research are indicated, in particular, the creation of low pH-stable electrocatalysts and novel strategies for the preparation of 1÷3D single-atom catalysts.

In this study, the quasi-static and dynamic mechanical behaviors and the energy absorption capacity of closed-cell aluminum foams with uniform and graded densities were experimentally studied. The effects of density, strain rate, and graded density on the mechanical performances of aluminum foams were quantitatively evaluated. It was shown that the density had a significant effect on the quasi-static and dynamic compressive stress of aluminum foams. Moreover, impact compression experiment results revealed that aluminum foam was sensitive to the strain rate. As the strain rate increased, the plateau stress and energy absorption capacity increased distinctly and the rate of deformation increased correspondingly. Finally, the investigation of aluminum foams with uniform and graded densities to study their deformation and failure mechanisms, mechanical characteristics, and energy absorption capacities showed that the GD 0.48-IV specimen exhibited superior impact resistance. The present work can provide a valuable reference for the optimum design of aluminum foam against impact loading.

This study investigates the effect of C on the deformation mechanisms in Fe–C alloys by molecular dynamics simulations. In uniaxial tensile simulations, the face-centered-cubic (fcc) structures of Fe–C alloys undergo the following deformation processes: (i) fcc→body-centered-cubic (bcc) martensitic transformation, (ii) deformation of bcc phase, and (iii) bcc→hcp martensitic transformation, which are significantly influenced by the C concentration. For the low C concentrations (0–0.8 wt%) fcc phase, the fcc→bcc phase transformation accords a two-stage shear transformation mechanism based on the Bain model, the deformation mechanism of the bcc phase is the first migration of twinning structures and then elastic deformation, and the bcc→hcp phase transformation follows Burgers relations resulting from the shear of the bcc close-packed layers. However, for the fcc phase with high C concentrations (1.0–2.0 wt%), the fcc→bcc phase transformation follows a localized Bain transformation mechanism impeded by the C atoms, the bcc phase only experiences elastic deformation, and the bcc→hcp phase transformation also conforms to Burgers relations but become localized due to the addition of more C atoms. Because of the different phase transformation mechanisms between the high C and low C supercells, the dislocation generation mechanism is also different.

To overcome the steric effect of norbornene (NB), first-generation Grubbs’ catalyst (GC1) was used as the catalyst to graft NB onto the polypropylene (PP) chain by reactive extrusion. Instead of harsh reaction conditions, such as anhydrous, which was the general method to synthesize NB polymers, this convenient method would be easier to industrialize. The mechanism of grafting was studied by using Fourier Transform InfraRed spectra and differential scanning calorimetry. It was found that GC1 could initiate the ring-opening metathesis polymerization of NB to obtain short NB chain-grafted PP-g-NB. The rheological behavior showed that the grafted NB short chains on PP-g-NB increase the shear thinning of the polymers and decrease the system viscosity.

In this paper, the Lewis base character of 3-aminopropyltrimethoxysilane (3-APTMS), an imine derivative of siloxane, and an indole monomer were shown to enable the reduction of gold cations in acetone. The Lewis acid–base adduct of indole monomers and gold formed a polyindole–gold nanoparticle sol. Similarly, the Lewis acid–base adduct of 3-APTMS and gold enabled the formation of gold nanoparticles in the presence of acetone. The polyindole–gold nanoparticle sol and siloxane–gold nanoparticles underwent self-assembly into a polymeric nanofluid that was suitable for casting membranes. The use of these membranes as a potentiometric ion sensor for both cations and anions was considered; a common nonspecific ion exchange molecule, sodium tetraphenylborate, and the polymeric nanofluid were used to prepare an anion sensor and a cation sensor.

This article presents a comprehensive overview of currently available research on bioimplantable energy harvesters, with a specific focus on their fabrication and issue of biocompatibility. Both the achievements and limitations of the field are pointed out from the standpoint of materials science and engineering as directions for future research. Particular attention is paid to the controversy over the use of lead-based or lead-free piezoelectric ceramics in biomedical applications, which is closely related to different temporalities of research on biological conditions. This report is intended to serve as a reference guide for developing the next generation of piezoelectric biomedical devices.

This research investigates a novel composite of encapsulated paraffin in boron nitride nanotube (BNNT) which is more thermally and chemically stable than carbon nanotube. This composite can achieve high thermal conductivity and, meanwhile, have thermal energy storage capability for efficient thermal management under extreme conditions. Equilibrium molecular dynamics simulations were conducted to study self-diffusion coefficient, thermal conductivity, and specific heat of encapsulated paraffin. The simulation results indicated that the self-diffusion coefficient and thermal conductivity of paraffin could be increased by up to 10 and 7 times, respectively, while specific heat was reduced after encapsulating into BNNT.

In this research, the mechanical alloying (MA) technique was used to study solid solubility in the immiscible Zr–Cr alloy system. At first, Zr and Cr powders were milled, and then, the phase evolution, alloying mechanism, microstructural change, and mechanical properties of the milled powders were investigated by X-ray diffraction technique, scanning electron microscopy along with energy dispersive spectroscopy, transition electron microscopy, and microhardness measurements. Moreover, the solubility limit of Zr in Cr lattice was obtained by Vegard's law. The results showed that the MA was significantly enhanced the solubility of Zr in Cr up to about 21.6 wt% after an optimum milling time of 32 h and led to form an amorphous/nanocrystalline composite of Zr-reach and Cr-reach supersaturated solid solutions with the microhardness value of 503 Hv approximately. Also, the thermodynamic analysis indicated that the Gibbs free energy changes for the amorphous and solid solution were positive, which were provided by the MA process.