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The polymer/solvent/nonsolvent ternary solutions have been previously used for fabricating electrospun macroporous fibers, in which the nonsolvent was expected to induce a liquid–liquid phase separation that leads to formation of pores after drying. In this study, we demonstrate that the poly(styrene‐co‐acrylonitrile) (SAN)/chlorobenzene (CB)/dimethyl sulfoxide (DMSO) system can be successfully electrospun into highly uniform macroporous fibers with pore size >50 nm at CB/DMSO volume ratio ~7/3 though both CB and DMSO are good solvents to SAN. The results imply that a premixed nonsolvent is not necessary for the formation of macropores. We find that it is the water droplets condensed from the atmosphere that work as the nucleation sites to trigger the phase separation while water‐miscible DMSO plays a supporting role to expand the solvent‐rich phase and the resultant pore size. Instead of solvent quality, the distinct volatilities and water miscibilities of the solvents are the keys. The macropores throughout the fibers provide high surface areas and large openings on surface such that the fibers show a significant improvement in oil adsorption capacity in comparison to the smooth and mesoporous ones. [ABSTRACT FROM AUTHOR]

Alkali-free set accelerators are added at the nozzle to ensure rapid set of wet sprayed concrete. The accelerator affects the strength development, porosity and transport properties, and hence the durability, of the sprayed concrete. We developed a method to cast samples with varying set accelerator doses to measure the effect of the accelerator on porosity, but with a constant effective water/binder ratio of 0.45 for each accelerator dose. Six cylinders of concrete were cast with set accelerator doses of 0, 2, 4, 6, 8 and 10 % of effective binder mass. High workability was achieved to enable mixing before rapid stiffening occurred, though this high workability led to some aggregate settlement in the cylinders. Porosity was measured by capillary suction on dried specimens of hardened concrete and subsequent pressure saturation of macro pores (PF test). The samples cast with higher doses of set accelerator had higher suction porosities and higher rates of capillary suction. Using a modified Powers equation gave very low calculated degree of hydration values for concrete with set accelerator, indicating that the equation is not applicable for concrete with set accelerators, due to the higher suction porosity in accelerated matrices, caused by different hydration products. [ABSTRACT FROM AUTHOR]

In photo-electrochemical etching for macroporous silicon, the electrolyte diffusion in the macropore greatly influences the formation of macroporous silicon, especially the etching rate and macropore diameter. In this study, the electrolyte diffusion was investigated systematically. We focused on the establishment of the electrolyte diffusion model and its impact on the etching rate and macropore diameter. By solving the diffusion equation, the electrolyte diffusion model was deduced, which is different from the commonly accepted model. The main difference is that, in the model, the HF concentration at the macropore tip decreases nonlinearly with macropore length. The module can effectively predict the etching rate. Based on this model, the practical method of etching current density adjustment for fabricating high aspect ratio macroporous silicon was proposed. In addition, the samples were fabricated with a constant etching current density and corrected etching current density. The experimental result indicates that the novel electrolyte diffusion model is practical. The finding from this study shows that the adjustment of etching current density based on the electrolyte diffusion model can effectively control the macropore diameter of high aspect ratio macroporous silicon. [ABSTRACT FROM AUTHOR]

Programmed, reshaping hydrogel architectures were fabricated from sugar/hydrogel inks via a three-dimensional printing method involving a stimuli-responsive polymer. We developed a new hydrogel ink composed of monomers (acrylamide [AAm]) and N-isopropylacrylamide [NIPAAm]), and sugar (mixture of glucose and sucrose) as a pore-generator, enabling to improve printability by increasing the ink's viscoelastic properties and induce the formation of macropores in the hydrogel architectures. This study demonstrated that creating macropores in such architectures enables rapid responses to stimuli that can facilitate four-dimensional printing. We printed bilayer structures from monomer inks to which we had added sugar, and we exposed them to processes that cross-linked the monomers and leached out the sugar to create macropores. In comparison with a conventional poly(N-isopropylacrylamide) hydrogel, the macroporous hydrogels prepared using polymerization in the presence of a high concentration of sugar showed higher swelling ratios and exhibited much faster response rates to temperature changes. We used rheometry and scanning electron microscopy to characterize the properties of these inks and hydrogels. The results suggest that this method may provide a readily available route to the rapid design and fabrication of shape-morphing hydrogel architectures with potential application in soft robotics, hydrogel actuators, and tissue engineering. [ABSTRACT FROM AUTHOR]

Hierarchical porous textures of carbon‐based electrode materials are advantageous for applications in supercapacitors, owing to their reasonable pore size distribution and large surface area. In this work, a facile yet effective one‐step carbonization method for the preparation of hierarchical porous carbons (HPCs) derived from interpenetrating polymer networks (IPNs) of phenol‐formaldehyde resin (PF) and sodium polyacrylate (PAAS) is proposed. Phenol‐formaldehyde prepolymer can be introduced into the inter network space of PAAS to form IPNs in which only hydrogen‐bonding interactions exist between them. During the carbonization process of IPNs, the PF networks tend to form a carbon matrix, which generates large amounts of micropores. While the PAAS evaporates into gaseous products, serving as a template for micro‐, meso‐, and macropores. Due to such synergistic effects, a carbon material with a large surface area of 1764 m2 g−1 and a large pore volume of 1.111 cm3 g−1 is constructed with an interconnected hierarchical porous carbon network structure. With such unique carbon structure characteristics, the electrode material of HPC delivers a high specific capacitance of 201 F g−1 at 0.5 A g−1 and excellent cyclability of approximately 100 % of capacitance retention after 10000 cycles. The ideal capacitive behavior from IPNs provides new insights for the production of carbonaceous materials for high‐performance supercapacitors applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Microporous ZIF-8 and hierarchical porous ZIF-8 with high crystallinity and good stability have been synthesized. • There are mesopores and macropores in hierarchical porous ZIF-8 crystals. • The formation mechanism of hierarchical porosity is clarified. • Hierarchical porous ZIF-8 can provide more active sites than microporous ZIF-8 for adsorption of antibiotics. Abstract Aiming for improve mass transfer rate of antibiotics adsorption from water, a strategy of building larger pores (>2 nm) in microporous MOFs has been put forward. However, most of reported approaches are complicated and inefficient. Herein, a facile one-spot approach to fabricate hierarchical porous Zeolitic Imidazolate Framework-8 (HpZIF-8) was developed, where poly(diallyldimethylammonium chloride) (PDDA) was selected as structure-directing agent to modulate the growth of microporous ZIF-8 (mZIF-8). The final products with meso- and macropores exhibit hierarchical porosity. The mechanism was a two-step process: First, crystal nucleus aggregated initiated by electrostatic interaction between cationic PDDA and deprotonated 2-MI anions. Second, Ostwald ripening process and orientated growth occurred with further growth of crystals. For removing Tetracycline Hydrochloride (TH) and Chloramphenicol (CP) from water, hierarchical porous HpZIF-8-10(D) (D = 1.0, 1.5, 2.0) showed larger adsorption capacity than mZIF-8-10 despite of decreased BET surface area, which could be attributed to novel hierarchical porous structures. The adsorption kinetics and isotherms of TH and CP by HpZIF-8-10(1.5) were analyzed. The strategy present here may provide new thoughts for designing more abundant MOF structures and further expand their application range. [ABSTRACT FROM AUTHOR]

Abstract We synthesized Fe foams using water suspensions of micrometric Fe 2 O 3 powder by reducing and sintering the sublimated Fe oxide green body to Fe under 5% H 2 /Ar gas. The resultant Fe foam showed aligned lamellar macropores replicating the ice dendrites. The compressive behavior and deformation mechanism of the synthesized Fe foam were studied using an acoustic emission (AE) method, with which we detected sudden localized structural changes in the Fe foam material. The evolution of the deformation mechanism was elucidated using the adaptive sequential k -means (ASK) algorithm; specifically, the plastic deformation of the cell struts was followed by localized cell collapse, which eventually led to fracturing of the cell walls. For potential biomedical applications, the corrosion and biocompatibility characteristics of the two synthesized Fe foams with different porosities (50% vs. 44%) were examined and compared. Despite its larger porosity, the superior corrosion behavior of the Fe foam with 50% porosity can be attributed to its larger pore size and smaller microscopic surface area. Based on the cytotoxicity tests for the extracts of the foams, the Fe foam with 44% porosity showed better cytocompatibility than that with 50% porosity. Graphical abstract Unlabelled Image Highlights • Iron foam synthesized from water suspension of Fe 2 O 3 powder under 5% H 2 /Ar gas. • Compressive deformation mechanism of iron foam is analyzed using an acoustic emission. • Not porosity but pore size is a dominant factor for corrosion behavior of iron foams. • Concentration released Fen+ controls cytotoxicity of iron foam extracts. [ABSTRACT FROM AUTHOR]

Abstract Silicate-substituted hydroxyapatite scaffolds containing multiscale porosity are manufactured. Model parts containing macropores of five cross-sectional geometries (circle, square, rhombus, star and triangle) and two sizes are shaped by microstereolithography. Three open microporosity contents (0.5, 23 or 37 vol%) are introduced in the ceramic. MC3T3-E1 pre-osteoblasts are seeded onto these scaffolds. Analysis of cell colonization inside the macropores after 7 and 14 days of cultivation shows that the cellular filling is proportional to the macropore size and strongly influenced by macropore shape. Straight edges and convex surfaces are detrimental. High aspect ratios, the absence of reentrant angles and the presence of acute angles, by creating concavities and minimizing flat surfaces, facilitate cell colonization. Rhombus and triangle cross-sections are thus particularly favorable, while square and star geometries are the least favored. An increase in the microporosity content strongly impairs cell growth in the macropores. The data are statistically analyzed using a principal components analysis that shows that macro- and microtopographical parameters of scaffolds must be collectively considered with correlated interactions to understand cell behavior. The results indicate the important cell sensing of topography during the initial step of cell adhesion and proliferation and evidence the need for an optimized scaffold design. Graphical abstract Unlabelled Image Highlights • Model micro-macroporous SiHA scaffolds are shaped by microstereolithography. • Microporosity and macropore architecture affect cell colonization. • Impacts of macropore geometries features on cell ingrowth are discussed. • High microporosity content is deleterious for cell growth in the macropores. • Surface macro- and microtopographical parameters must be considered collectively. [ABSTRACT FROM AUTHOR]

Abstract Ni Mo catalysts supported on hierarchically macro-mesoporous alumina were prepared and applied to the hydrodesulfurization (HDS) of dibenzothiophene (DBT). The alumina supports with different macroporous structures (either parallel macropores or interconnected macropores) were synthesized by two methods, hydrolysis of aluminum tri-sec-butoxide and dual-template approach. All hierarchically porous structured Ni-Mo/Al 2 O 3 catalysts showed higher HDS activities when compared to a Ni-Mo/Al 2 O 3 with only mesopores, which were mainly due to the enhanced diffusion by macropores. In particular, a dual-template derived catalyst with highly interconnected macropores and large porosity displayed the best activity, which remained stable during a long-term test of 100 h. Graphical abstract Unlabelled Image Highlights • Hierarchically macro-mesoporous Ni-Mo/Al 2 O 3 catalysts showed high HDS activity. • The improved activity was mainly ascribed to the enhanced diffusion by macropores. • The metal-support interaction affected to some extent the HDS activity of catalyst. • The best catalyst developed showed good stability during 100 h of test. [ABSTRACT FROM AUTHOR]

Pure ice particles have been used as porogens to prepare bone tissue engineering scaffolds for several years. However, it is difficult to prepare an ideal spherical ice porogen to improve the pore structure of the porous scaffolds. In this work, sublimable ice-based microspheres were prepared by spraying the 1,4-dioxane/water (70/30, v/v) solution through a syringe needle into liquid nitrogen. Ice-based microspheres have suitable melting points (− 4 °C) and high sublimation rate. The sieved ice-based microspheres with a size of 380-500 μm were used as a porogen to prepare porous PLLA scaffold. The calculation results show that the surface tension of the solution and the interfacial tension between the solution and liquid nitrogen are small when the volume ratio of the 1,4-dioxane/water is 70/30. The 1,4-dioxane/water solution can be effectively dispersed into small droplets in liquid nitrogen and rapidly frozen into microspheres. Scanning electron microscope images show that the porous PLLA scaffold had good pore connectivity. Macropores and micropores can be observed in the cross section of the PLLA scaffold. The pore wall has a special rough structure, and many micro-/nano-PLLA fibers can be found on the surface of the pore wall. [ABSTRACT FROM AUTHOR]

Highlights • New insights are provided on the influence of conducting polymer surface morphology on neuronal signal transduction. • Methods for reproducible synthesis of macroporous PEDOT/PSS alongside are presented. • Macroporous PEDOT/PSS polymerised at 632 mC cm−2 improves electrochemistry of untemplated PEDOT/PSS. • Biocompatibility, viable neuronal recording and stimulation is demonstrated by both untemplated and macroporous PEDOT/PSS coatings. Abstract Recent trends towards smaller electrodes for improved spatial resolution have seen the rise of rough electrode coatings, such as conducting polymer (CPs), to increase electrochemical surface area and subsequently recording and stimulation performance. Here, we directly compare the influence of macropores in poly(3,4-ethylenedioxythiophene)/polystyrene sulphonate (PEDOT/PSS) coatings hypothesised to further increase electrochemical surface area and gain new insights into the influence of surface morphology on CP signal transduction. Macroporous PEDOT/PSS polymerised at the highest charge density of 637 mC cm−2 displayed significant reductions in impedance magnitude (at 100 Hz) and thermal noise and significant increases in the charge injection limit when compared to untemplated PEDOT/PSS. Macroporous PEDOT/PSS was more susceptible to delamination following long-term biphasic stimulation, however, it displayed an interesting improvement in impedance throughout the experiment. Biocompatibility of both untemplated and macroporous PEDOT/PSS coatings alongside primary hippocampal neurons in-vitro was demonstrated via neuronal viability assays. Improvements were noted in electrochemical properties achieved by the macroporous coatings, meanwhile in-vitro recording and stimulation performance favoured untemplated PEDOT/PSS as measured through signal-to-noise ratios and direct neuronal responses to biphasic stimuli, respectively. Whilst the macroporous structures perform similarly to untemplated PEDOT/PSS in-vitro , the significant improvement in their electrochemical surface area at high deposition charge densities may offer them use in fields of drug delivery and biosensing. [ABSTRACT FROM AUTHOR]

Abstract Microstructural and mass transport properties of compacted Na- and Cs-montmorillonites (Na-MMT and Cs-MMT) with different swelling properties at dry densities of 0.8 and 1.25 Mg m−3 were investigated by combining three-dimensional microstructure analysis using nanofocus X-ray computed tomography (CT), X-ray diffractometry (XRD), and through diffusion measurement of deuterated water (HDO). The X-ray CT and XRD observations indicated that macropores (micrometer- and submicrometer-sized pores) in the dry state of compacted Na-MMT are filled with gel phases, and the grain sizes of clay particles shifted toward smaller values through the saturation and swelling processes. By contrast, no gel phase and no decrease in the grain and pore volumes were observed for saturated Cs-MMT. The D e of HDO of Na-MMT was reduced by half compared to that of Cs-MMT owing to the high swelling capacity of Na-MMT and the occupation of macropores with gel phases. The geometrical factors of the macropores, including tortuosity (τ) and geometric constrictivity (δ g), in the dry and saturated states of compacted Na-MMT and Cs-MMT were estimated from three-dimensional images of the macropores (and gel phases in saturated Na-MMT) and from the results of their statistical analysis. The estimated geometric factor (δ g /τ 2) of saturated Cs-MMT was consistent with the corresponding D e / εD 0 values derived in the HDO diffusion experiment. In the case of Na-MMT, the larger differences between the geometric factors (δ g /τ 2) evaluated by nanofocus X-ray CT and the D e / εD 0 values derived by the diffusion tests can be explained by the electrostatic constrictivity factor and the additional geometrical factors in gel phase and interlayer that are smaller than the detection limit of the nanofocus X-ray CT. Highlights • Microstructural and diffusion properties of compacted Na- and Cs-montmorillonites. • Three-dimensional microstructure analysis using nanofocus X-ray CT. • Geometric factors of the macropores, including tortuosity and constrictivity. • Comparison of geometric factors from diffusion test and X-ray CT. [ABSTRACT FROM AUTHOR]

Design and synthesis of magnetic macroporous metal-organic frameworks (MOFs) have been of significant interest, in order to improve the catalytic efficiency and reusability. In this work, we prepared magnetic macroporous MOF composites based on as-prepared magnetic macroporous polyacrylamides (MMPam). Different MOFs with or without unsaturated coordinative metal sites, including HKUST-1, MOF-2, UiO-66, and Fe-MIL-101(-NH2) were grown on and within the MMPam matrices. The composites showed hierarchical porosity with both micro- and macropores, which facilitated substrate diffusion to increase the conversion for isomerization of α-pinene oxide from 62% in the case of pure HKUST-1 microparticles to 90% in the case of HKUST-1@MMPam. The magnetic property also endowed the composites with easy recovery and reasonable reusability. [ABSTRACT FROM AUTHOR]

Graphical abstract An eco-friendly raw kaolinite was used as a novel support to synthesize a highly efficient S/ZA-Kao macroporous solid acid catalyst for typical esterification reactions of oleic acid with methanol and acetic acid with n -butanol in the synthesis of green biofuels. Highlights • A raw kaolinite-supported SO 4 2−/ZnAl 2 O 4 macroporous solid acid was synthesized. • The dispersion, textural and properties of catalysts can be adjusted to optimum. • Biodiesel produced via oleic acid esterification with the conversion of 70.1%. • Bio-oils upgraded via acetic acid esterification with the conversion of 98.2%. • Improved reusability was showed in acetic acid and oleic acid esterification. Abstract A series of raw kaolinite-supported SO 4 2−/ZnAl 2 O 4 (S/ZA-Kao) macroporous solid acid catalysts were synthesized and applied in esterification of both oleic acid with methanol and acetic acid with n -butanol for the biofuels synthesis. The structures and acidic properties of S/ZA-Kao catalysts were characterized by means of XRD, FE-SEM, EDS, BET, FT-IR (direct and NH 3 adsorbed), NH 3 -TPD, TG and XPS. The results indicated the mass ratio of ZnAl 2 O 4 /kaolinite played a significant role in adjusting the active components dispersion, textural and acidic properties. The optimal S/ZA-Kao(6:4) catalysts performed the macroporous structure and the high dispersion of active components, which might be the essential reason for its improved acid sites and reduced limitation of mass transfer. As a result, the macroporous solid acid exhibited superior conversion of 98.2% in acetic acid esterification and 70.1% in oleic acid esterification. The kinetic study demonstrated that the relatively lower values of activation energy over the S/ZA-Kao(6:4) macroporous solid acid, further confirming that the macroporous solid acid was highly efficient for the biofuel synthesis via esterification. Moreover, the further investigation indicated the catalytic activities were closely related to the ratio of Brönsted acid sites on catalysts. Besides, S/ZA-Kao(6:4) macroporous solid acid particularly displayed excellent reusability, which was due to its structural stability and high dispersion of active components. [ABSTRACT FROM AUTHOR]

Abstract Understanding the sources and transit times of water that generates streamflow in headwater streams is important for understanding catchment functioning. This study determines the water sources and transit times in first-order streams from a temperate rainforest in the Otway Ranges, southeast Australia. Comparison of the major ion geochemistry of soil water, water flowing through soil pipes (macropores), and groundwater from the riparian zone adjacent to the stream suggests that water from soil pipes is the major contributor to streamflow. The tritium (3H) activities of the stream water are between 1.80 and 2.06 TU, the water from the soil pipes has 3H activities between 1.80 and 2.25 TU, the riparian zone groundwater has 3H activities of 1.35–2.39 TU, and one sample of soil water has a 3H activity of 2.22 TU. These 3H activities are significantly lower than those of local modern rainfall (2.6–3.0 TU), and mean transit times calculated using a range of lumped parameter models are between 3 and 57 years. These estimates are consistent with the major ion and stable isotope data, which imply that mean transit times were sufficiently long to allow weathering of minerals and/or organic matter and evapotranspiration to occur. The long mean transit times imply that water flows in this upper catchment are buffered against year-on-year variations in rainfall, but may change due to longer-term variations in rainfall or landuse. Graphical abstract Image 1 Highlights • Upper catchment stream water provided largely by macropores. • Riparian groundwater and some soil water isolated from the stream. • Mean transit times of all waters are between 3 and 57 years. • Long mean transit times imply resilience to short-term climate fluctuations. [ABSTRACT FROM AUTHOR]

Abstract Porosity of scaffolds plays an indispensable role in tissue regeneration. In this paper, hierarchical scaffolds with tailored macro/micro-porosity architectures for bone tissue engineering applications were introduced. Poly (vinyl alcohol) (PVA) has been innovatively blended into poly (lactic acid) (PLA) to fabricate composite filaments for fused deposition modeling (FDM). Customized macropores (pore size > 100 μm) of scaffolds were designed and precisely fabricated by FDM process. Then the blended scaffolds were subjected to gas foaming process to create micropores (pore size < 10 μm), which are hardly created by using 3DP techniques. Subsequently, PVA phase in the scaffolds was extracted by solvent etching method to create open pores, which are hard to create in gas foaming. The results showed that the scaffolds with 100–800 μm macropores can be precisely fabricated by FDM technique. Meanwhile, 2–10 μm micropores were successfully created. These novel scaffolds have the potential to be used in bone tissue regeneration. [ABSTRACT FROM AUTHOR]

Etching rate is a major concern for the effective mass production of high-aspect-ratio microstructures, especially in p-type silicon. In this work, controlled electrochemical growth of high-aspect-ratio (from 15 to 110) macropores in p-type silicon at ultrafast etching rate (from 16 to 30 µm min−1) has been studied. Based on current-burst-model, pore formation was systematically investigated from the nucleation phase to stable pore growth. Good macropores with depth up to 180 µm and aspect ratio beyond 110 was achieved in just 11 min. This sets a new record on state-of-the-art p-type silicon microfabrication and can promote the development of microdevices. High-aspect-ratio macropores at ultrahigh etching rate were achieved in p-type silicon, which sets a novel record among p-type silicon microfabrication and can promote the effective mass production of microdevices. [ABSTRACT FROM AUTHOR]

Abstract The macropore composite beads were prepared as CO 2 adsorbent by polymerization of polyacrylamide and impregnation of 1,2-epoxyhexane functionalized poly(ethyleneimine). The consecutive CO 2 adsorption-desorption tests were performed at 1 bar in the range of 50–125 °C. The time required to achieve 90% CO 2 uptake (2.64 mmol·g−1) is less than 10 min, and 90% CO 2 desorption can be realized within 11 min. After 50 cycles of adsorption-desorption, the adsorption capacity declines 9.2 wt.%. According to the adsorption-desorption thermodynamics without consideration of the heat recovery, the calculated regeneration heat is 2.2 MJ·kg−1(CO 2). The attrition resistance of the spherical beads was tested in a bubbling fluidized-bed reactor, and the attrition ratio is 0.30 wt.%·h−1 at 130 °C. These results indicate that the synthesized adsorbent possesses high adsorption efficiency, low desorption energy, and good attrition resistance performance, showing good application prospects for CO 2 capture in fluidized-bed reactors. Highlights • Spherical polyHIPE supports were prepared with suitable pores structure. • Impregnated EH/PEI make for high CO 2 uptake but low desorption temperature. • The attrition rate is 0.30 wt.%·h−1 at 130°C. • Calculated regeneration heat of adsorbent is 2.2 MJ·kg−1(CO 2). [ABSTRACT FROM AUTHOR]

A metallurgical material integration concept, using porous calcium titanate (CaTiO 3 ) as raw material, was put forward for preparation of metallic titanium powder and porous titanium by calciothermic reduction. Porous metallic titanium was prepared by calcium vapor reduction at 1273 K for 6 h with two types of interconnected pores in titanium samples. The interconnected macropores about 50–300 μm were inherited from porous CaTiO 3 , and the micropores about 5–40 μm were made by leaching removal of byproduct CaO in reduction products. Metallic porous titanium was fabricated in Ca-dissolved CaO-CaCl 2 molten salt mixtures by self-sintering and had a good interconnectivity inside with thickness about 155 μm and the porosities of the porous titanium are 65–81%. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Innterconnected porous architecture is critical for tissue engineering scaffold as well as biomimetic nanofibrous structure. In addition, a paradigm shift is recently taking place in the scaffold design from homogeneous porous scaffold to heterogeneous porous scaffold for the complex tissues. In this study, a versatile and simple one-pot method, dual phase separation, is developed to fabricate macroporous nanofibrous scaffold by phase separating the mixture solutions of immiscible polymer blends without using porogens. The macropores in the scaffold are interconnected, and their size can be tuned by the polymer blend ratio. Moreover, benefiting from the easy operation of dual phase separation technique, an innovative, versatile and facile two-step phase separation method is developed to fabricate heterogeneous porous layered nanofibrous scaffolds with different shapes, such as bilayered tubular scaffold and tri-layered cylindrical scaffold. The bilayered tubular nanofibrous scaffold composed of poly(l -lactic acid) (PLLA)/poly(l -lactide-co-ε-caprolactone) (PLCL) microporous inner layer and PLLA/poly(ε-caprolactone) (PCL) macroporous outer layer matches simultaneously the functional growth of endothelial cells (ECs) and smooth muscle cells (SMCs), and shows the favorable performance for potential small diameter blood vessel application. Therefore, this study provides the novel and facile strategies to fabricate macroporous nanofibrous scaffold and heterogeneous porous layered nanofibrous scaffold for tissue engineering applications. Statement of Significance The fabrication of porous tissue engineering scaffold made of non-water-soluble polymer commonly requires the use of porogen materials. This is complex and time-consuming, resulting in greater difficulty to prepare heterogeneous porous layered scaffold for multifunctional tissues repair, such as blood vessel and osteochondral tissue. Herein, a novel, versatile and simple one-pot dual phase separation technique is developed for the first time to fabricate porous scaffold without using porogens. Simultaneously, it also endows the resultant scaffold with the biomimetic nanofibrous architecture. Based on the easy operation of this dual phase separation technique, a facile two-step phase separation method is also put forward for the first time and applied in fabricating heterogeneous porous layered nanofibrous scaffold for tissue engineering applications. [ABSTRACT FROM AUTHOR]

Cryogels are synthetic polymers used in adsorption experiments in recent years. Because of their macropores, they provide an excellent advantage as an adsorbent in continuous and batch adsorption processes. In this study, nicotinamide (NAA) decorated poly(2-hydroxyethyl methacrylate-glycidyl methacrylate), poly(HEMA-GMA), cryogels were synthesized. Heavy metal adsorption was carried out in wastewater obtained from six different sources in Çorum, Turkey. This study has a novelty regarding the application, i.e., it is the first time to use a polymeric adsorbent for the removal of 15 different heavy metal at the same time without any competition (despite the fact that there is a competition between the metals, the only thing is the removal regarding the purpose the study) as a heavy metal sweeper. Inductively coupled plasma-mass spectrometer (ICP-MS) was used for the determination of the initial amount of heavy metal in the wastewater samples. Adsorption studies were performed using poly(HEMA-GMA) and NAA-decorated poly(HEMA-GMA) cryogel to see the effect of NAA decoration. Higher adsorption capacity was achieved using NAA decorated poly(HEMA-GMA) cryogel. The total heavy metal amount adsorbed from six different sources was about 686 and 387 mg for poly(HEMA-GMA)-NAA and poly(HEMA-GMA) cryogels, respectively. The highest heavy metal adsorption value was obtained in the wastewater from source 2, and Zn (II) was the heavy metal adsorbed most for both cryogel. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermal, surface area, elemental, and computerized microtomography (μCT) analyses were used for the characterization of cryogels. [ABSTRACT FROM AUTHOR]

Tectonism significantly affects the pore type and pore structure evolution of organic-rich shale. The Lower Cambrian Lujiaping Shale in the northeastern of the upper Yangtze area is a significant marine shale being studied for shale gas exploration in South China. Here, we use two groups of Lujiaping Shale samples, such as brittle deformation shales (BDS) and ductile deformation shales (DDS), to investigate the relationship between tectonism and pore structure using a combination of mineralogy, organic geochemistry, low-pressure nitrogen adsorption, low-field nuclear magnetic resonance (NMR), optical microscopy, and high-resolution scanning electron microscopy (SEM). Results indicate that the samples are quartz, carbonate, and clay rich. Total organic carbon (TOC) content ranges between 2.27% and 5.88%, and vitrinite reflectance ( R o ) measured between 2.95% and 4.11%. Helium porosity lies between 3.02% and 4.66% in BDS and 3.16%-4.29% in DDS. In addition, four major pore types can be identified and classified by their formation mechanism, location, geometry, and connectivity, which we named type I (pore within or between organic and mineral particles), type II (pore in admixtures), type III (micro-channel), and type IV (micro-fracture). Under the BDS, the interparticle (interP) pores, micro-channels, and micro-fractures are more developed, the macropores (＞50 nm) increase, the connectivity and porosity are enhanced. The intraparticle (intraP) pores, micro-channels, and micro-fractures are dominant in DDS, the micropores (< 2 nm) increase and the connectivity is enhanced, whereas the porosity decreases. Meanwhile, pore network within the admixtures of organic matter (OM) and clays can also contribute to gas storage and migration pathways in both BDS and DDS, in addition to other pore types. However, OM pores are poorly-developed in samples. Our findings provide a key component for further evaluation of the exploration and development potential of the Lujiaping Shale in the complex tectonic areas of South China. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract This study investigated the effects of incorporating glucose microparticles (GMPs) and poly(lactic-co-glycolic acid) microparticles (PLGA MPs) within a calcium phosphate cement on the cement’s handling, physicochemical properties, and the respective pore formation. Composites were fabricated with two different weight fractions of GMPs (10 and 20 wt%) and two different weight fractions of PLGA MPs (10 and 20 wt%). Samples were assayed for porosity, pore morphology, and compressive mechanical properties. An in vitro degradation study was also conducted. Samples were exposed to a physiological solution for 3 days, 4 wks, and 8 wks in order to understand how the inclusion of GMPs and PLGA MPs affects the composite’s porosity and mass loss over time. GMPs and PLGA MPs were both successfully incorporated within the composites and all formulations showed an initial setting time that is appropriate for clinical applications. Through a main effects analysis, we observed that the incorporation of GMPs had a significant effect on the overall porosity, mean pore size, mode pore size, and in vitro degradation rate of PLGA MPs as early as after 3 days (p < 0.05). After 4 wks and 8 wks, these same properties were affected by the inclusion of both types of MPs (p < 0.05). Advanced polymer chromatography confirmed that the degradation of PLGA MPs coincided with an increase in composite porosity, mean pore size, and mode pore size. Finally, it was observed that the inclusion of GMPs slowed the degradation of PLGA MPs in vitro and reduced the solution acidity due to PLGA degradation products. Our results suggest that the dual inclusion of GMPs and PLGA MPs is a valuable approach for the generation of early macropores, while also mitigating the effect of acidic degradation products from PLGA MPs on their degradation kinetics. Statement of significance A multitude of strategies and techniques have been investigated for the introduction of macropores with calcium phosphate cements (CPC). However, many of these strategies take several weeks to months to generate a maximal porosity or the degradation products of the porogen can trigger a localized inflammatory response in vivo. As such, it was hypothesized that the fast dissolution of glucose microparticles (GMPs) in a CPC composite also incorporating poly(lactic-co-glycolic acid) (PLGA) microparticles (MPs) will create an initial macroporosity and increase the surface area within the CPC, thus enhancing the diffusion of PLGA degradation products and preventing a significant decrease in pH. Furthermore, as PLGA degradation occurs over several weeks to months, additional macroporosity will be generated at later time points within CPCs. The results offer a new method for generating macroporosity in a multimodal fashion that also mitigates the effects of acidic degradation products. [ABSTRACT FROM AUTHOR]

Hierarchically porous materials have drawn extensive attention to construct effective air cathodes in newly developed zinc-air batteries. Here, we successfully fabricated hierarchically porous carbon microspheres (HCMs) with fully open and interconnected super-macropores by a strategy of high internal phase W/O/W double emulsions (HIPDEs). The as-prepared HCMs-supported platinum nanoparticles (Pt/HCMs) were employed as novel ORR catalysts for the air cathodes of Zn-air batteries. It was found that Pt/HCMs promised a nearly 100% Pt utilization and showed a higher current density and better durability than the commercial Pt/C on rotating disk electrode (RDE) setup and gas diffusion electrode (GDE)-based half-cell configurations, highlighting the importance of the fully open and interconnected super-macropores for improving the gas/liquid phases transport. Benefiting from the superior mass transfer, the Pt/HCMs-based Zn-air battery delivered high power density (190 mW cm −2 ) and specific capacity (800 mA h g Zn −1 ) comparable to that of the commercial Pt/C-based battery. This study presents a new avenue to engineer catalyst to boost the performance of Zn-air batteries. [ABSTRACT FROM AUTHOR]

Hierarchically porous materials offer the opportunity for catalyst development in regards to improving catalytic performances. In the present work, the combination of latex synthesis, sonochemical reduction and two-step catalysed sol-gel process has been demonstrated to be a versatile method for preparing supported catalysts with tailored hierarchical porosity. This method has been used to prepare porous Pt/SiO2 catalysts with mesopore and macropore size ranges as large as 2-15 nm and 90-400 nm, respectively. These hierarchically porous catalysts presented an excellent catalytic performance for the selective hydrogenation of p-chloronitrobenzene (p-CNB) to p-chloroaniline (p-CAN). Selectivity values up to 100% at 80% conversion of p-CNB and initial reaction rates up to 74.0 molCNB/min molPt were obtained, while a commercial catalyst exhibited both a lower selectivity of 90.8% and a lower initial reaction rate of 47.7 molCNB/min molPt. [ABSTRACT FROM AUTHOR]

The influence of the variations in the photoelectrochemical etching regimes of macropores in n-Si (within the limits of V. Lehmann optimums) on the quality of structures was studied. At some regimes, generation of screw (cylindrical or spiral) dislocations during the etching process under normal conditions was observed. First, dislocations are formed, and then macropores are etched, mainly on near-surface traces of dislocations. We call this process “auto-revealing”. The values of residual lattice distortions due to deformation of the silicon plate during the etching process were determined by x-ray diffraction on a structure obtained in the acceptable boundary regime. [ABSTRACT FROM AUTHOR]

Directional freeze-casting of ceramic slurries followed by freeze drying and partial sintering results in materials with highly anisotropic properties parallel and transverse to the freezing direction. Physical measurements and optical dilatometry confirm that, during sintering, freeze-cast structures experience more strain along their freezing direction than transverse to it. Discrete Element (DEM) simulations of equivalent freeze-cast structures confirm this behavior. These simulations indicate that not only is sintering anisotropic on the macroscopic scale but within the walls and macropores themselves. It was determined that the anisotropic particle contact network that resulted from the aligned macropores led to anisotropic shrinkage during sintering. [ABSTRACT FROM AUTHOR]

Mesoporous bioactive glass (MBG) has a greater surface area and pore volume than conventional BG. Hence, MBG is useful as a drug delivery carrier. Previously, MBG has been fabricated as dense or porous blocks. Compared to blocks, microbeads have a greater flexibility to fill different-shaped cavities with close packing. Moreover, fibrous materials have proven to increase cell attachment and differentiation because they mimic the three-dimensional structure of the natural extracellular matrix (ECM). Macroporous materials possess porous structures with interconnecting channels that allow the invasive growth of cells and capillaries. Hence, the aim of this study was to fabricate macroporous microbeads containing MBG nanofibres (MMBs). We used poly(methyl methacrylate) (PMMA) microspheres as the macroporous template in the process and removed the PMMA microspheres after the calcination treatment. Scanning electron microscopy imaging showed multiple pores on the surface of the MMBs, and a micro-computed tomography image showed the presence of pores throughout the entire microbead. The cellular attachment of MG63 osteoblast-like cells was considerably higher on the MMBs than on glass beads after culturing for 4 h. However, the cell viability greatly decreased after culturing for 1 day. We speculated that the release of a high concentration of calcium ions from the MMBs decreased the cell viability. To improve the cell viability, we modified the MMBs by immersing the MMBs in a simulated body fluid to fabricate a thin apatite layer on the surface of the MMBs. The apatite-modified MMBs (Ap-MMB) decreased the release of calcium ions and improved the cell viability. In an animal study, the bone defect in the control group did not recover. In contrast to the control group, the Ap-MMBs in the defect were nearly filled with new bone. The results show that the Ap-MMBs have great potential in osteogenesis for bone tissue engineering. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) porous N, O-doped carbon with hierarchical structures composed of micropores, mesopores and macropores were synthesized by the direct carbonization of kelp with a “self-activation” process. The as-obtained 3D N, O-doped carbon remained abundant N and O functional groups and the BET specific surface area measured 656 m 2  g −1 . 3D hierarchical porous structures with the pore size ranged from several nanometers to hundred nanometers and lots of pores were attributed to mesopores with the average pore size of about 5.4 nm. Electrochemical properties of the 3D hierarchical porous N, O-doped carbon as a supercapactior (SC) electrode were investigated and it delivered excellent capacitance of 669 mF cm −2 at 1 mA cm −2 due to its 3D hierarchical porous structures with high specific surface area which is beneficial for improving ionic storage and transportation in electrodes. This kelp-derived carbon exhibited excellent cyclic performance with the retention of 104% after 10,000 cycles. A flexible solid-state symmetric SC (SSC) device was fabricated using the 3D hierarchical porous N, O-doped carbon and delivered an excellent capacitance of 412 mF cm −2 at 2 mA cm −2 and satisfying cyclic stability with the retention of 85% after 10,000 cycles. The areal energy density of the SSC device reach up to 0.146 mWh cm −2 at the power density of 0.8 mW cm −2 . This facile route for low-cost carbonaceous materials with novel architecture and functionality can be as a promising alternative to synthesize biomass carbon for practical SC application. [ABSTRACT FROM AUTHOR]

Oral drugs present the most convenient, economical, and painless route for self-administration. Despite commercialization of multiple technologies relying on micro- and nanocrystalline drugs, research on microparticles (MPs) based oral biopharmaceuticals delivery systems has still not culminated well enough in commercial products. This is largely due to the drugs being exposed to the destabilizing environment during MP synthesis process, and partly because of complicated process conditions. Hence, we developed a solvent swelling-evaporation method of producing pH-responsive MPs with micron-sized macropores using poly(methacrylic acid-co-ethyl acrylate) in 1:1 ratio (commercial name: Eudragit® L100-55 polymer). We investigated the effects of temperature and evaporation time on pore formation, freeze-drying induced pore closure, and the release profile of model drugs (fluorescent beads, lactase, and pravastatin sodium) encapsulated MPs in simulated gastrointestinal tract conditions. Encapsulated lactase/pravastatin maintained >60% of their activity due to the preservation of pore closure, which proved the potential of this proof-of-concept microencapsulation system. Importantly, the presence of macropores on MPs can be beneficial for easy drug loading, and solve the problem of bioactivity loss during the conventional MP fabrication-drug encapsulation steps. Therefore, pH-sensing MPs with macropores can contribute to the development of oral drug formulations for a wide variety of drugs and bio-macromolecules, having a various size ranging from genes to micron-sized ingredients with high therapeutic efficacy. [ABSTRACT FROM AUTHOR]

12Porous glass-ceramics were produced by sponge replication for possible use as orbital implant materials, characterized from a morphological viewpoint, and compared to commonly used devices. Favorable characteristics of these new materials for ocular applications include total porosity above 50 vol.%, presence of open and large macropores (>200 lm) that could potentially allow fibrovascular tissue ingrowth, and submicronic surface roughness which is significantly lower than that of commercial "gold standard" alumina implants. The last feature is key to limit the risk of postoperative conjunctival abrasion and to achieve clinical success. Therefore, these glass-ceramic porous materials are highly promising alternatives to existing ceramic orbital implants. [ABSTRACT FROM AUTHOR]

The effects of supercritical CO 2 (scCO 2 ) on coal pores play a critical role in CO 2 geological storage-enhanced coalbed methane recovery (CO 2 -ECBM). To investigate the effects of scCO 2 on the pore structure and connectivity in coals of different ranks, CO 2 sequestration processes were replicated using a scCO 2 geochemical reactor. Four coal samples with different ranks were exposed to scCO 2 and water for 240 h under 80 °C and 20 MPa. Mercury intrusion porosimetry, nitrogen adsorption tests, and scanning electron microscopy analysis were used to identify the pore volume, pore size distribution, pore connectivity, and pore morphology of the coal samples before and after scCO 2 -H 2 O treatment. The increase in the macropore volume caused by the scCO 2 is mainly controlled by the pores >30 μm, resulted from the dissolution of carbonate minerals with large grain size in organic matter. The coal rank has a positive influence on the volume and specific surface area of the pores >30 μm, whereas coal rank is more significant for macropore specific surface area in the high-volatile bituminous coal and macropore volume in the low-volatile bituminous, semi-anthracite, and anthracite coal. With an increase in the coal rank, the volume and specific surface area of the mesopores increase. The changes in the mesopore volume in the high-volatile bituminous coal are caused by changes in the pores 20–50 nm in diameter, while these changes in the low-volatile bituminous coal, semi-anthracite, and anthracite are caused by changes in the pores <20 nm, due to the formation of dissolution-created pores in minerals; additionally, many pores <3 nm are generated by the scCO 2 . At the macropore scale, the scCO 2 increases the volume of the non-effectively interconnected pores more than that of the effectively interconnected pores, indicating that the scCO 2 has a weak effect on the increase in macropore connectivity. The volume of the effectively interconnected pores increases more at the mesopore scale than at the macropore scale, and the scCO 2 treatment increases the connectivity of the mesopores. [ABSTRACT FROM AUTHOR]

The hierarchical porous carbon/MnO composites were prepared from the homogenous mixture of potassium humate and manganese nitrate via one-step carbonization at 700 °C. Manganese nitrate in precursors has a synergistic catalysis effect with potassium element on the pore forming, also leads to an increased oxygen content of as-prepared composite. The PH-Mn-0.1 displays a hierarchical porosity with a moderate surface area of 776 m2 g−1 and total pore volume of 0.487 cm3 g−1, and MnO nanoparticles were uniformly deposited on the porous carbon matrix with a Mn content of 6.7 wt%. When used as electrode material for two-electrode symmetric supercapacitor, the PH-Mn-0.1 delivers higher volumetric capacitance of 276 F cm−3 at a current density of 50 mA g−1, consisting of pseudocapacitance related to MnO nanoparticles and electric double layer capacitance, a maximum energy density of 7.45 Wh kg−1 and low electrochemical resistance. Moreover, the PH-Mn-0.1 shows an enhanced rate capability due to its improved wettability, and novel cycle performance with an increasing specific capacitance during the 1000 charge-discharge cycles at 2500 mA g−1. [ABSTRACT FROM AUTHOR]

Abstract: Free‐standing macroporous air electrodes with enhanced interfacial contact, rapid mass transport, and tailored deposition space for large amounts of Li2O2 are essential for improving the rate performance of Li‐O2 batteries. An ordered mesoporous carbon membrane with continuous macroporous channels was prepared by inversely topological transformation from ZnO nanorod array. Utilized as a free‐standing air cathode for Li‐O2 battery, the hierarchically porous carbon membrane shows superior rate performance. However, the increased cross‐sectional area of the continuous macropores on the cathode surface leads to a kinetic overpotential with large voltage hysteresis and linear voltage variation against Butler–Volmer behavior. The kinetics were investigated based on the rate‐determining step of second electron transfer accompanied by migration of Li+ in solid or quasi‐solid intermediates. These discoveries shed light on the design of the air cathode for Li‐O2 batteries with high‐rate performance. [ABSTRACT FROM AUTHOR]

A highly active catalyst Keggin type POM-based inorganic-organic compound POM@MOF-199@LZSM-5(PMZ) has been prepared and applied in the catalytic oxidative desulfurization system. Structure and properties of catalyst were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), N 2 adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and so on. The catalyst gave high desulfurization activity in the removal of DBT using O 2 as the oxidant. Under the optimal conditions, the conversion rate reached 100% only in 120 min. The kinetic studies revealed that the oxidative desulfurization can present a pseudo first-order kinetic process and the apparent activation energy was 30.5 kJ/mol. The response surface method also used to optimize the process of oxidative desulfurization. There was little change for the oxidative desulfurization efficiency after 10 recycle times. This enhanced catalytic performance could be attributed to the more filled active species, POM, in the larger porous materials and the good protection measures of dual-function porous material supports. [ABSTRACT FROM AUTHOR]

Carbon microbeads with diameters of a few hundreds of microns are produced by dropping chitosan acetate (CA) solution in liquid nitrogen, freeze drying and thermal treatment in inert atmosphere at 700 °C. The structure of the beads is characterized by hierarchical porosity at the three length scales: (i) macropores originating from the phase separation during the water ice crystal grow inside the droplets, immersed in liquid nitrogen, (ii) mesoporores arising in course of the beads thermal treatment, leading to the removal of the porogen molecules (Pluronic F127) added to the CA solution and (iii) micropores induced by the carbonization of chitosan resin. The carbon beads have a rigid skin which present wrinkles with well-defined structure. The carbon bead pore size and volume could be tuned with glyoxal and glyoxylic acid which are able to cross-link in a different manner with chitosan as showed by 13 C NMR. The beads are produced by a green process employing entirely biosourced and renewable materials that make them attractive for the large scale applications requiring nanoporous carbons. [ABSTRACT FROM AUTHOR]

Poly(ethylene glycol) diacrylate (PEGDA) cryogels, particularly useful for biotechnological applications, are currently fabricated exploiting crosslinking systems that require long freezing/crosslinking times (20 h or longer). The aim of this work was to assess whether fast UV irradiation (up to 60 s) of frozen PEGDA solutions could be an advantageous alternative for cryogel production. By using different polymer concentrations and UV times, cryogels with highly interconnected macropores (about 50–90 μm) were produced. A gelation yield in the range 60–80% was recorded, with higher values obtained for low PEGDA concentrations (5 and 10% w/v). Interestingly, while decreasing the swelling and increasing the stiffness of the cryogels, a higher polymer concentration was also found to reduce the pore size. Furthermore, increasing the UV time resulted in significantly higher swelling and larger pores for 10% PEGDA samples, while having negligible effect on other cryogel types and/or features. Although deserving further exploration, fast UV irradiation is an effective method to produce PEGDA cryogels with tunable properties. [ABSTRACT FROM AUTHOR]

Herein, we successfully dispersed nickel nitride nanosheets (Ni 3 N NSs) on various carbon matrices (i.e. graphene, macroporous carbon, carbon nanotube and hollow carbon fiber) through nitridation treatment of precursors. Characterization results demonstrated that Ni 3 N-PCF (hollow and porous carbon fiber) owned the 3D hollow and tubular architecture, abundant meso/macropores and large BET surface area compared with other control samples. Ni 3 N-PCF exhibit the best H 2 O 2 and glucose detection abilities than another four samples because of the synergistic effect of metallic character of Ni 3 N , excellent electroconductibility of PCF and structural advantages of hierarchically meso/macroporous architectures. It afforded wide linear ranges (from 0.001 to 2.08 mM and 2.08–50.50 mM) and large sensitivity values (51.81 and 38.32 uA cm −2  mM −1 ) for H 2 O 2 detection. Furthermore, it also displayed wide linear ranges (0.001–1.75 mM and 1.75–9.18 mM), large sensitivity values (1620.31 and 856.40 uA cm −2  mM −1 ) and a small response time (1.7 s) toward glucose detection. In addition, Ni 3 N-PCF can be used for detecting glucose concentrations in blood serums with satisfying results. Ni 3 N-PCF also revealed good reproducibility, good stability, and superior selectivity toward either H 2 O 2 or glucose detection. This work opens new approach for boosting electroanalysis abilities of Ni based materials. [ABSTRACT FROM AUTHOR]

A self-standing macroporous noble metal-zinc oxide (ZnO) sponge of robust 3D network has been fabricated through in-situ growth method. The key to the construction of the bioinspired sponge lies in the choice of commercial polyurethane sponge (CPS) with interconnected and junction-free macroporous structure as the skeleton to support Au/ZnO nanorods (Au/ZnONRs). The resultant Au/ZnO/CPS not only exhibits hierarchical structures representing physical features of CPS, but also demonstrates durable superior photocatalytic activity and hydrogen generation capability. In addition, we have adopted various irradiations to investigate the effect of UV light and visible light on the photocatalytic performance of Au/ZnO/CPS individually. In detail, the photocatalytic properties of Au/ZnO/CPS and ZnO/CPS have been monitored and compared under irradiations of different wavelengths (200–1100, 350–780, 200–420 and 420–780 nm) for 90 min to reveal the effect of irradiation wavelength on the activity of photocatalysts. A possible mechanism between irradiation wavelength and photocatalytic degradation efficiency is proposed. The facile in-situ growth approach presented herein can be easily scaled up, affording a convenient method for the preparation of self-standing 3D macroporous materials, which holds great potential for the application in both environmental purification and solar-to-hydrogen energy conversion. [ABSTRACT FROM AUTHOR]

The novel three-dimensionally ordered macroporous (3DOM) CaO/SiO2, 3DOM CaO/Al2O3, and 3DOM Ca12Al14O32Cl2 catalysts for biodiesel transesterification were prepared by sol-gel method. The 3DOM catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The hierarchical porous structure was achieved; however, only 3DOM CaO/Al2O3 and 3DOM Ca12Al14O32Cl2 catalysts were used for transesterification due to high amount of active CaO. Various parameters such as methanol to oil molar ratio, catalyst concentration, reaction time, and their influence on the biodiesel production were studied. The result showed that 99.0% RPO conversion was achieved using the 3DOM Ca12Al14O33Cl2 as a catalyst under the optimal condition of 12 : 1 methanol to oil molar ratio and 6 wt.% catalyst with reaction time of 3 hours at 65°C. [ABSTRACT FROM AUTHOR]

Abstract: The applications of three‐dimensional superstructures that consist of metal–organic framework (MOF) crystals are promising, but limited by spatial control over the crystallization process. Here a hydrophobic hierarchical metal–organic framework (HZIF‐8) containing unusual micro‐, meso‐, and macropores was designed and synthesized by a template strategy, in which the polystyrene (PS) not only acted as the template to construct the macropores, but also modified the hydrophilic crystal surface of ZIF‐8. When used as adsorbent for liquid oil/water separation, HZIF‐8 demonstrated significantly enhanced oil adsorption performance while maintaining very low water uptake. [ABSTRACT FROM AUTHOR]

In this work, it is demonstrated that hierarchical mesoporous silica monoliths (HMSMs) with trimodal porosities can be facilely prepared using P123 as structure-directing agent and tetraethoxysilane as precursor. In such HMSMs, classic co-continuous macrostructures with interconnected macropores and smooth isotropic skeletons can be obtained in a tunable way, depending on the synthesis variables, including the amounts of P123 and 1,3,5-trimethylbenzene and acid concentrations. Skeletons feature randomly oriented SBA-15-type primary particles with 2D hexagonally ordered mesochannels largely accessible from bimodal macropores. Co-continuous macropore size of a typical HMSM (P1.2) is 19.6 μm, intra-skeleton macropore of 1.9 μm and mesopore size of 9.9 nm. The BET surface area by N 2 sorption and total pore volume by Archimedes principle reach 590 m 2 g -1 and 3.56 cm 3 g -1 , respectively. Based on systematic study on the relationship between synthetic compositions and porous structures, the ternary diagram and formation mechanism of these HMSMs were analyzed. [ABSTRACT FROM AUTHOR]

The photoelectrochemical etching of solar-grade n-type silicon in a 4% solution of HF in dimethylformamide is experimentally studied. The pore morphology, porosity, effective valence, and etching rate are examined in relation to the applied voltage, illumination intensity of the sample's backside, and process duration. It is found that the anodization of n-Si in an organic electrolyte substantially differs from that in aqueous solutions. This is manifested in that, at a voltage exceeding the threshold value, in the so-called breakdown mode, macropores with vertical walls begin to multiply and branch intensively due to the appearance of side pores. The appearance of secondary pores is accompanied by an increase in porosity, a decrease in the propagation velocity of the porous front deeper into the substrate, and rapid transition to the electropolishing mode. In the breakdown mode at a low illumination level, a fractal structure of macropores propagating along certain crystallographic directions is observed: <100> and along the previously unobserved <111>. It is demonstrated that the morphology of macropores can be controlled in the course of anodization by passing from one mode to another upon changing the external parameters: voltage or illumination. It is shown that using an organic electrolyte makes it possible to obtain macroporous membranes with a porosity substantially exceeding that of macroporous membranes formed in aqueous electrolytes under the same conditions. [ABSTRACT FROM AUTHOR]

The development of a general method for the facile synthesis of hierarchical porous metal–organic frameworks (H-MOFs) with tunable porosities is important because of their widespread applications. Herein, through the ingenious use of different neutral organic amines as templates, we report the development of a green and versatile method to synthesize three H-MOFs (Cu-BTC, ZIF-8, and ZIF-90) with tunable morphologies and porosities. The selected neutral amine template molecules deprotonated organic ligands and facilitated the formation of H-MOFs while guiding the formation of meso- and macropores. These high quality as-synthesized H-MOFs possessed micro-, meso-, and macropore hierarchical structures and high thermal stability after the amine templates were removed by simple washing and drying. The as-prepared Cu-BTC H-MOFs exhibited more than 2 times higher activity than conventional microporous Cu-BTC in catalyzing Henry reaction. Our facile strategy establishes a green and general route to synthesize a large variety of H-MOFs for various applications, particularly when large molecules or biomolecules are involved. [ABSTRACT FROM AUTHOR]

A novel three-dimensionally (3D) ordered hierarchically porous polypyrrole (3DOHPPy) is successfully synthesized via a simple chemical polymerization method by using silica colloidal crystals as templates. The 3DOHPPy possesses a large BET specific surface area (118.5 m 2  g −1 ), 3D ordered interconnected macropores (240 nm) and mesopores (2–3 nm) on the macropore walls. The sulfur/3DOHPPy (S/3DOHPPy) composite is prepared by a solution-diffusion route followed by low-temperature heat treatment and studied as a cathode material for the lithium/sulfur (Li/S) battery. The resulting S/3DOHPPy cathode shows a high specific discharge capacity of 751 mAh g −1 even after 100 cycles at 0.1 C and great rate capability. The superior electrochemical property of the S/3DOHPPy composite is ascribed to the unique hierarchical structure of 3DOHPPy with ordered interconnected macropores that benefit enhanced mass transfer and the small mesopores on the macropore walls that can immobilize the sulfur and polysulfides produced during the discharge/charge processes. [ABSTRACT FROM AUTHOR]

Photocatalysts with a hierarchically porous structure have attracted considerable attention owing to their wide pore size distribution and high surface area, which enhance the efficiency of transporting species to active sites. In this study, hierarchically meso-macroporous TiO 2 photocatalysts decorated with highly dispersed CdS nanoparticles were synthesized via hydrolysis, followed by a hydrothermal treatment. The textural mesopores and interconnected pore framework provided more accessible active sites and efficient mass transport for the photocatalytic process. The light collection efficiency was enhanced because of multiple scattering of incident light in the macropores. Moreover, the formation of a heterojunction between the CdS and TiO 2 nanoparticles extended the photoresponse of TiO 2 to the visible-light range and enhanced the charge separation efficiency. Therefore, the hierarchically meso-macroporous TiO 2 /CdS photocatalysts exhibited excellent photocatalytic activity for the degradation of rhodaming B under visible-light irradiation. Trapping experiments demonstrated that superoxide radicals ( O 2 − ) and hydroxyl radicals ( OH) were the main active species in photocatalysis. A reasonable photocatalytic mechanism of TiO 2 /CdS heterojunction photocatalysts was also presented. [ABSTRACT FROM AUTHOR]

This paper introduces a rational design and synthesis of three-dimensional (3-D) zeolitic imidazole frameworks (ZIF-8) derived carbon/NiAl-LDH core-shell composite for high performance supercapacitor. The ZIF-8 derived carbon polyhedrons templated growth of LDH nanoplatelets gives rise to coexistence of micro/meso/macropores and optimized synergistic effect in the stable 3-D core-shell structure. Remarkably, the composite shows excellent capacitive performances originating from the considerable charge storage and electroactive species exposure as well as high ion diffusion rate. This work highlights the strategy of structure design in constructing composite materials with optimized synergistic effect, which greatly promotes the supercapacitor development. [ABSTRACT FROM AUTHOR]

Carbon-NaCl composites with high NaCl loading (83.3 to 92.2 wt%) were prepared by setting molten sucrose-NaCl-glycerol pastes in a stainless steel mold at 160 °C. The carbonization of the composites followed by NaCl removal by washing with water produced low-density microcellular carbon foams. The setting of the paste was due to the caramelization of molten sucrose as well as the slow evaporation of glycerol. The carbon-NaCl composites had the adequate compressive strength (6.9 to 17.8 MPa) and ductility for machining using conventional machine tools. Machining of the carbon-NaCl composites followed by NaCl removal was used as a strategy to produce low-density carbon foams with desired contours. The glycerol not only decreased the density of carbon foams produced from the sucrose-NaCl system but also produced a remarkable change in the foam microstructure from a combination of macropores and microcells to only microcells of sizes predominantly in the range of 3 to 6 μm. Carbon foams prepared at NaCl to sucrose weight ratios in the range of 1.5 to 3 show density, compressive strength, thermal conductivity and EMI shielding effectiveness in the ranges of 0.096 to 0.214 g/cm 3 , 0.60 to 4.83 MPa, 0.087 to 0.235 Wm − 1 K − 1 and 24.7 to 41.7 dB, respectively. [ABSTRACT FROM AUTHOR]

A multiscale methodology combining three different reactor length-scales is presented to investigate the role of the catalyst internal pore structure and metal loading and dispersion on the catalyst layer and full-scale reactor performances. At the catalyst level, the methodology involves pore-scale simulations in the three-dimensional mesopore and macropore space. The information gathered at the catalyst level is delivered to the full-scale reactor model. The methodology is applied to a honeycomb reactor performing methane partial oxidation considering reaction kinetics described through a detailed multistep reaction mechanism. Realistic mesopore and macropore structures were reconstructed and combined to form specific bidisperse porous washcoat layers. The study shows that species effective diffusivities vary significantly but not in the same proportion for different structures. For structures featuring poor transport characteristics, the integral methane conversion and hydrogen selectivity are strongly affected while the reactor temperatures increase substantially. © 2017 American Institute of Chemical Engineers AIChE J, 64: 578-594, 2018 [ABSTRACT FROM AUTHOR]