Transparent wood composites provide new functionalities through active additives distributed at the nanoscale. Scalable nanotechnology includes processing where nanoparticles and molecules are brought into the dense wood cell wall. A novel cell wall swelling step through green chemistry is therefore investigated. Sub-zero centigrade NaOH treatment provides extensive cell wall swelling. Cell wall accessibility is vastly increased so that chemicals can readily impregnate the nanostructured cell wall. Transparent wood with a thickness of up to 15 mm can therefore be fabricated. The optical transmittance and the attenuation coefficient are improved since the polymer is distributed inside the cell wall as a matrix for the nanoscale cellulose fibrils. The proposed technology paves the way for scalable wood nanoengineering.

Zeolites are crystalline microporous materials constructed by corner-sharing tetrahedra (SiO₄ and AlO₄), with many industrial applications as ion exchangers, adsorbents and heterogeneous catalysts. However, the presence of micropores impedes the use of zeolites in areas dealing with bulky substrates. Introducing extrinsic mesopores, that is, intercrystal/intracrystal mesopores, in zeolites is a solution to overcome the diffusion barrier. Still, those extrinsic mesopores are generally disordered and non-uniform; moreover, acidity and crystallinity are always, to some extent, impaired. Thus, synthesizing thermally stable zeolites with intrinsic mesopores that are of uniform size and crystallographically connected with micropores, denoted here as intrinsic mesoporous zeolite, is highly desired but still not achieved. Here we report ZMQ-1 (Zeolitic Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, no. 1), an aluminosilicate zeolite with an intersecting intrinsic meso-microporous channel system delimited by 28 × 10 × 10-rings, in which the 28-ring has a free diameter of 22.76 Å × 11.83 Å, which reaches the mesopore domain. ZMQ-1 has high thermal and hydrothermal stability with tunable framework Si/Al molar ratios. ZMQ-1 is the first aluminosilicate zeolite with an intrinsic meso-microporous channel system. The Brønsted acidity of ZMQ-1 imparts high activity and unique selectivity in the catalytic cracking of heavy oil. The position of the organic structure-directing agent (OSDA) used for ZMQ-1 synthesis was determined from three-dimensional electron diffraction (3D ED) data, which shows the unique structure-directing role of the OSDA in the formation of the intrinsic meso-microporous zeolite. This provides an incentive for preparing other stable mesopore-containing zeolites.

Hierarchical assembly is used to construct complex materials using elementary building units, mainly depending on the non-covalent interactions involving dynamic bonds. Here we present a hierarchical assembly strategy to build highly crystalline tubular frameworks. A multi-level assembly process driven by dynamic covalent bonds and coordination bonds is shown to produce a supramolecular nanotubular framework and three tubular covalent organic frameworks (COFs). These materials consist of well-ordered triangular nanotubes assembled in an oriented manner. In tubular COFs, the spacing between adjacent nanotubes can be systematically adjusted by altering the connector lengths to create mesoporous structures with adjustable pore size. Moreover, reversible transformations between tubular COFs and layered COFs were achieved by the reversible addition and removal of Zn(NO3)2. The facile demetallation–remetallation process confers tuneable structural properties to the materials and enables the layered COFs to serve as efficient ‘sponges’ for metal ions. This study represents a notable advance in hierarchical assembly; incorporating covalent bonding into this process is expected to greatly accelerate the development of new materials. (Figure presented.)

The structure of novel large pore borosilicate zeolite EMM-59 (|C₁₉H₄₂N₂|₈[B_5.2Si_218.8O₄₄₈]) with localized framework boron sites was determined by using three-dimensional electron diffraction (3D ED) and scanning transmission electron microscopy (STEM) imaging. EMM-59 was synthesized using 2,2-(cyclopentane-1,1-diyl)bis(N,N-diethyl-N-methylethan-1-aminium) as an organic structure-directing agent (OSDA). The framework has a three-dimensional intersecting channel system delimited by 12 × 10 × 10-ring openings and contains 28 T and 60 oxygen atoms in the asymmetric unit, making it the most complex monoclinic zeolite. The 3D ED data collected from as-made EMM-59 under cryogenic conditions revealed three symmetry-independent locations of the OSDAs, and STEM imaging showed that the OSDAs are flexible and adopt different molecular conformations in channels with identical structural environments. The framework boron atoms were exclusively found in T-sites of 4-rings, especially those shared by multiple 4-rings. The tetrahedral BO₄ with the highest boron content (38.6%) was transformed into a trigonal BO₃ after the OSDAs were removed upon calcination. Its location and boron content could also be identified by STEM imaging.

We report the one-pot synthesis of a chabazite (CHA)/erionite (ERI)-type zeolite intergrowth structure characterized by adjustable extents of intergrowth enrichment and Si/Al molar ratios. This method utilizes readily synthesizable 6-azaspiro[5.6]dodecan-6-ium as the exclusive organic structure-directing agent (OSDA) within a potassium-dominant environment. High-throughput simulations were used to accurately determine the templating energy and molecular shape, facilitating the selection of an optimally biselective OSDA from among thousands of prospective candidates. The coexistence of the crystal phases, forming a distinct structure comprising disk-like CHA regions bridged by ERI-rich pillars, was corroborated via rigorous powder X-ray diffraction and integrated differential-phase contrast scanning transmission electron microscopy (iDPC S/TEM) analyses. iDPC S/TEM imaging further revealed the presence of single offretite layers dispersed within the ERI phase. The ratio of crystal phases between CHA and ERI in this type of intergrowth could be varied systematically by changing both the OSDA/Si and K/Si ratios. Two intergrown zeolite samples with different Si/Al molar ratios were tested for the selective catalytic reduction (SCR) of NOx with NH3, showing competitive catalytic performance and hydrothermal stability compared to that of the industry-standard commercial NH3-SCR catalyst, Cu-SSZ-13, prevalent in automotive applications. Collectively, this work underscores the potential of our approach for the synthesis and optimization of adjustable intergrown zeolite structures, offering competitive alternatives for key industrial processes.

Pharmaceutical active compounds (PhACs) are some of the most recalcitrant water pollutants causing undesired environmental and human effects. In absence of adapted decontamination technologies, there is an urgent need to develop efficient and sustainable alternatives for water remediation. Metal–organic frameworks (MOFs) have recently emerged as promising candidates for adsorbing contaminants as well as providing photoactive sites, as they possess exceptional porosity and chemical versatility. To date, the reported studies using MOFs in water remediation have been mainly focused on the removal of a single type of PhACs and rarely on the combined elimination of PhACs mixtures. Herein, the eco-friendly bismuth-based MOF, SU-101, has been originally proposed as an efficient adsorbent-photocatalyst for the elimination of a mixture of three challenging persistent PhACs, frequently detected in wastewater and surface water in ng L⁻¹ to mg·L⁻¹ concentrations: the antibiotic sulfamethazine (SMT), the anti-inflammatory diclofenac (DCF), and the antihypertensive atenolol (At). Adsorption experiments of the mixture revealed that SU-101 exhibited a great adsorption capacity towards At, resulting in an almost complete removal (94.1 ± 0.8% for combined adsorption) in only 5 h. Also, SU-101 demonstrated a remarkable photocatalytic activity under visible light to simultaneously degrade DCF and SMT (99.6 ± 0.4% and 89.2 ± 1.4%, respectively). In addition, MOF-contaminant interactions, the photocatalytic mechanism and degradation pathways were investigated, also assessing the toxicity of the resulting degradation products. Even further, recycling and regeneration studies were performed, demonstrating its efficient reuse for 4 consecutive cycles without further treatment, and its subsequent successful regeneration by simply washing the material with a NaCl solution.

Cellulose, being a renewable and abundant biopolymer, has garnered significant attention for its unique properties and potential applications in hybrid materials. Understanding the hierarchical arrangement of cellulose nanofibers is crucial for developing cellulose-based materials with enhanced mechanical properties. In this study, the use of Scanning Electron Diffraction (SED) is presented to map the nanoscale orientation of cellulose fibers in a bio-composite material with a preserved wood cell structure. The SED data provides detailed insights into the ordering of cellulose with an extraordinary resolution of approximate to 15 nm. It enables a quantitative analysis of the fiber orientation over regions as large as entire cells. A highly organized arrangement of cellulose fibers within the secondary cell wall is observed, with a gradient of orientations toward the outer part of the wall. The in-plane fiber rotation is quantified, revealing a uniform orientation close to the middle lamella. Transversely sectioned material exhibits similar trends, suggesting a layered cell wall structure. Based on the SED data, a 3D model depicting the complex helical alignment of fibers throughout the cell wall is constructed. This study demonstrates the unique opportunities SED provides for characterizing the nanoscale hierarchical arrangement of cellulose nanofibers, empowering further research on a range of hybrid materials. Fundamental knowledge about the hierarchical arrangement of cellulose nanofiber is of great importance in developing new cellulose-based hybrid materials. Scanning electron diffraction is employed to map the cellulose nanofiber orientations throughout a wood-derived bio-based material. SED data reveals insights into cellulose alignment and enables precise quantitative fiber orientation analysis with a nanoscale spatial resolution.image

Transparent wood composites (TWs) offer the possibility of unique coloration effects. A colored transparent wood composite (C-TW) with enhanced fire retardancy was impregnated by metal ion solutions, followed by methyl methacrylate (MMA) impregnation and polymerization. Bleached birch wood with a preserved hierarchical structure acted as a host for metal ions. Cobalt, nickel, copper, and iron metal salts were used. The location and distribution of metal ions in C-TW as well as the mechanical performance, optical properties, and fire retardancy were investigated. The C-TW coloration is tunable by controlling the metal ion species and concentration. The metal ions reduced heat release rates and limited the production of smoke during forced combustion tests. The potential for scaled-up production was verified by fabricating samples with a dimension of 180 × 100 × 1 (l × b × h) mm³.

Despite the interest in proton exchange membrane (PEM)technologies(fuel cells and electrolyzers) for energy applications, the low stabilityof the electrolyte materials under working conditions (i.e., humidityand temperature) is one of their major limitations. Metal-organicframeworks (MOFs) have recently emerged as promising electrolytesdue to their higher stability compared with the currently appliedorganic polymers, proton conductivity, and outstanding porosity. Here,a novel robust Bi phosphonate MOF (branded as IEF-7) was successfullysynthesized and fully characterized, exhibiting an unusual topologydue to the irregular coordination geometry of the bismuth cations.Furthermore, IEF-7 exhibited potential porosity, very high chemicaland thermal stability, and free -PO3H groups involvedin its ultrahigh proton conductivity, reaching 1.39 x 10(-2) S cm(-1) at 90 degrees C and 90% relativehumidity for, at least, 3 cycles. In order to improve the consolidationand shaping of the powder for testing its ion conductivity properties,a highly MOF-loaded composite (90 wt %) was prepared by adding a protonconductive sulfonated polysulfone binder. The proton conductivityof the resulting composite was in the same order of magnitude as thecompacted MOF powder, making this polymeric composite electrolytevery promising for PEM technologies.

Photonic crystals are optical materials that are often fabricated by assembly of particles into periodically arranged structures. However, assembly of lignin nanoparticles has been limited due to lacking methods and incomplete understanding of the interparticle forces and packing mechanisms. Here we show a centrifugation-assisted fabrication of photonic crystals with rainbow structural colors emitted from the structure covering the entire visible spectrum. Our results show that centrifugation is crucial for the formation of lignin photonic crystals, because assembly of lignin nanoparticles without centrifugation assistance leads to the formation of stripe patterns rather than photonic crystals. We further prove that the functions of centrifugation are to classify lignin nanoparticles according to their particle size and produce monodispersed particle layers that display gradient colors from red to violet. The different layers of lignin nanoparticles were assembled in a way that created semi-closed packing structures, which gave rise to coherent scattering. The diameter of the lignin nanoparticles in each color layer is smaller than that predicted by a modified Bragg’s equation. In situ optical microscope images provided additional evidence on the importance of dynamic rearrangement of lignin nanoparticles during their assembly into semi-closed packing structures. The preparation of lignin nanoparticles combined with the methodology for their classification and assembly pave the way for sustainable photonic crystals.