The most common MXene composition Ti₃C₂T_x (T = F, O) shows outstanding stability as anode for sodium ion batteries (100% of capacity retention after 530 cycles with charge efficiency >99.7%). However, the reversibility of the intercalation/deintercalation process is strongly affected by the synthesis parameters determining, in turn, significant differences in the material structure. This study proposes a new approach to identify the crystal features influencing the performances, using a structural model built with a multitechnique approach that allows exploring the short-range order of the lamella. The model is then used to determine the long-range order by inserting defective elements into the structure. With this strategy it is possible to fit the MXene diffraction patterns, obtain the structural parameters including the stoichiometric composition of the terminations (neutron data), and quantify the structural disorder which can be used to discriminate the phases with the best electrochemical properties.

The study of the mechanisms by which mineral fibres promote adverse effects in both animals and humans is a hot topic of multidisciplinary research with many aspects that still need to be elucidated. Besides length and diameter, a key parameter that determines the toxicity/pathogenicity of a fibre is biopersistence, one component of which is biodurability. In this paper, biodurability of mineral fibres of social and economic importance (chrysotile, amphibole asbestos and fibrous erionite) has been determined for the first time in a systematic comparative way from in vitro acellular dissolution experiments. Dissolution was possible using the Gamble solution as simulated lung fluid (pH = 4 and at body temperature) so to reproduce the macrophage phagolysosome environment. The investigated mineral fibres display very different dissolution rates. For a 0.25 μm thick fibre, the calculated dissolution time of chrysotile is in the range 94–177 days, very short if compared to that of amphibole fibres (49–245 years), and fibrous erionite (181 years). Diffraction and SEM data on the dissolution products evidence that chrysotile rapidly undergoes amorphization with the formation of a nanophasic silica-rich fibrous metastable pseudomorph as first dissolution step whereas amphibole asbestos and fibrous erionite show minor signs of dissolution even after 9–12 months.

The structural composition, particle size on the nanoscale, phase state, and surface property have a significant impact on the performance of nanoalloy catalysts. Here we report a bimetallic Cu₃Pd nanoalloy anchored on a N-rich porous organic polymer (BBA-1), Cu₃Pd@BBA-1, which shows enhanced catalytic activity for the hydrodeoxygenation of vanillin, a typical compound of lignin-derived bio-oil. The prepared Cu₃Pd @BBA-1 bimetallic nanocatalyst exhibits highly efficient catalytic performance in promoting biomass refining compared with its monometallic counterparts, providing 99.3% conversion of vanillin with an exclusive selectivity of 93.6% for the hydrogenolysis product 2-methoxy-4-methylphenol. This catalyst is also found to have superior stability (reproducible conversion values upon several cycles), which represents a significant step forward in promoting biomass refining. The Cu₃Pd@BBA-1 and related Cu and Pd based catalysts with varying metallic molar ratios were synthesized by a polyol method using NaBH₄ as a strong reducing agent. The specific textural and chemical characteristics of the as-synthesized nanohybrid materials were comprehensively investigated by performing X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, synchrotron powder diffraction, X-ray absorption fine structure spectroscopy, ¹³C cross polarization magic angle spinning nuclear magnetic resonance, nitrogen physisorption, high resolution transmission electron microscopy, and high angle annular dark field scanning transmission electron microscopy with the corresponding elemental mapping. The catalytic performance of Cu₃Pd on other commercial supports such as Al₂O₃, TiO₂ and N-doped carbon is found to be inferior to that on BBA-1, revealing the important role of the nitrogen-rich porous organic polymer matrix. The performance of a 3 : 1 mixture of the monometallic nanoalloys was substantially lower than that of Cu₃Pd@BBA-1. These results and the inputs from the experimental probes used for the characterization indicate that in Cu₃Pd@BBA-1, alloying leads to improved surface conditions on the nanoscale and brings about a synergetic electronic effect, thus enabling an enhanced catalytic activity and good recyclability.