Balancing the Kinetic and Thermodynamic Synergetic Effect of Doped Carbon Molecular Sieves for Selective Separation of C2H4/C2H6.

Selective separation of ethylene and ethane (C2H4/C2H6) is a formidable challenge due to their close molecular size and boiling point. Compared to industry-used cryogenic distillation, adsorption separation would offer a more energy-efficient solution when an efficient adsorbent is available. Herein, a class of C2H4/C2H6 separation adsorbents, doped carbon molecular sieves (d-CMSs) is reported which are prepared from the polymerization and subsequent carbonization of resorcinol, m-phenylenediamine, and formaldehyde in ethanol solution. The study demonstrated that the polymer precursor themselves can be a versatile platform for modifying the pore structure and surface functional groups of their derived d-CMSs. The high proportion of pores centered at 3.5 Å in d-CMSs contributes significantly to achieving a superior kinetic selectivity of 205 for C2H4/C2H6 separation. The generated pyrrolic-N and pyridinic-N functional sites in d-CMSs contribute to a remarkable elevation of Henry selectivity to 135 due to the enhancement of the surface polarity in d-CMSs. By balancing the synergistic effects of kinetics and thermodynamics, d-CMSs achieve efficient separation of C2H4/C2H6. Polymer-grade C2H4 of 99.71% purity can be achieved with 75% recovery using the devised d-CMSs as reflected in a two-bed vacuum swing adsorption simulation.

An Active and Regenerable Nanometric High-Entropy Catalyst for Efficient Propane Dehydrogenation.

Propane dehydrogenation (PDH) is crucial for propylene production, but commercially employed Pt-based catalysts face susceptibility to deactivation due to the Pt sintering during reaction and regeneration steps. Here, we report a SiO2 supported nanometric (MnCoCuZnPt) high-entropy PDH catalyst with high activity and stability. The catalyst exhibited a super high propane conversion of 56.6% with 94% selectivity of propylene at 600 °C. The propylene productivity reached 68.5 molC3H6·gPt-1·h-1, nearly three times that of Pt/SiO2 (23.5 molC3H6·gPt-1·h-1) under a weight hourly space velocity of 60 h-1. In a high-entropy nanoparticle, Pt atoms were atomically dispersed through coordination with other metals and exhibited a positive charge, thereby showcasing remarkable catalytic activity. The high-entropy effect contributes to the catalyst a superior stability with a low deactivation constant of 0.0004 h-1 during 200 hours of reaction under the industrial gas composition at 550 °C. Such high-entropy PDH catalyst is easy regenerated through simple air combustion of deposited coke. After the fourth consecutive regeneration cycle, satisfactory catalytic stability was observed, and the element distribution of spent catalysts almost returned to their initial state, with no detectable Pt sintering. This work provides new insights into designing active, stable, and regenerable novel PDH catalysts.

Radiomics nomogram for the prediction of microvascular invasion of HCC and patients' benefit from postoperative adjuvant TACE: a multi-center study.

OBJECTIVES: To evaluate the performance of a radiomics nomogram developed based on gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid (Gd-EOB-DTPA) MRI for preoperative prediction of microvascular invasion (MVI) of hepatocellular carcinoma (HCC), and to identify patients who may benefit from the postoperative adjuvant transarterial chemoembolization (PA-TACE). METHODS: A total of 260 eligible patients were retrospectively enrolled from three hospitals (140, 65, and 55 in training, standardized external, and non-standardized external validation cohort). Radiomics features and image characteristics were extracted from Gd-EOB-DTPA MRI image before hepatectomy for each lesion. In the training cohort, a radiomics nomogram which incorporated the radiomics signature and radiological predictors was developed. The performance of the radiomics nomogram was assessed with respect to discrimination calibration, and clinical usefulness with external validation. A score (m-score) was constructed to stratify the patients and explored whether it could accurately predict patient who benefit from PA-TACE. RESULTS: A radiomics nomogram integrated with the radiomics signature, max-D(iameter) > 5.1 cm, peritumoral low intensity (PTLI), incomplete capsule, and irregular morphology had favorable discrimination in the training cohort (AUC = 0.982), the standardized external validation cohort (AUC = 0.969), and the non-standardized external validation cohort (AUC = 0.981). Decision curve analysis confirmed the clinical usefulness of the novel radiomics nomogram. The log-rank test revealed that PA-TACE significantly decreased the early recurrence in the high-risk group (p = 0.006) with no significant effect in the low-risk group (p = 0.270). CONCLUSIONS: The novel radiomics nomogram combining the radiomics signature and clinical radiological features achieved preoperative non-invasive MVI risk prediction and patient benefit assessment after PA-TACE, which may help clinicians implement more appropriate interventions. CLINICAL RELEVANCE STATEMENT: Our radiomics nomogram could represent a novel biomarker to identify patients who may benefit from the postoperative adjuvant transarterial chemoembolization, which may help clinicians to implement more appropriate interventions and perform individualized precision therapies. KEY POINTS: • The novel radiomics nomogram developed based on Gd-EOB-DTPA MRI achieved preoperative non-invasive MVI risk prediction. • An m-score based on the radiomics nomogram could stratify HCC patients and further identify individuals who may benefit from the PA-TACE. • The radiomics nomogram could help clinicians to implement more appropriate interventions and perform individualized precision therapies.

Added value of CE-CT radiomics to predict high Ki-67 expression in hepatocellular carcinoma.

BACKGROUND: This study aimed to develop a computed tomography (CT) model to predict Ki-67 expression in hepatocellular carcinoma (HCC) and to examine the added value of radiomics to clinico-radiological features. METHODS: A total of 208 patients (training set, n = 120; internal test set, n = 51; external validation set, n = 37) with pathologically confirmed HCC who underwent contrast-enhanced CT (CE-CT) within 1 month before surgery were retrospectively included from January 2014 to September 2021. Radiomics features were extracted and selected from three phases of CE-CT images, least absolute shrinkage and selection operator regression (LASSO) was used to select features, and the rad-score was calculated. CE-CT imaging and clinical features were selected using univariate and multivariate analyses, respectively. Three prediction models, including clinic-radiologic (CR) model, rad-score (R) model, and clinic-radiologic-radiomic (CRR) model, were developed and validated using logistic regression analysis. The performance of different models for predicting Ki-67 expression was evaluated using the area under the receiver operating characteristic curve (AUROC) and decision curve analysis (DCA). RESULTS: HCCs with high Ki-67 expression were more likely to have high serum α-fetoprotein levels (P = 0.041, odds ratio [OR] 2.54, 95% confidence interval [CI]: 1.04-6.21), non-rim arterial phase hyperenhancement (P = 0.001, OR 15.13, 95% CI 2.87-79.76), portal vein tumor thrombus (P = 0.035, OR 3.19, 95% CI: 1.08-9.37), and two-trait predictor of venous invasion (P = 0.026, OR 14.04, 95% CI: 1.39-144.32). The CR model achieved relatively good and stable performance compared with the R model (AUC, 0.805 [95% CI: 0.683-0.926] vs. 0.678 [95% CI: 0.536-0.839], P = 0.211; and 0.805 [95% CI: 0.657-0.953] vs. 0.667 [95% CI: 0.495-0.839], P = 0.135) in the internal and external validation sets. After combining the CR model with the R model, the AUC of the CRR model increased to 0.903 (95% CI: 0.849-0.956) in the training set, which was significantly higher than that of the CR model (P = 0.0148). However, no significant differences were found between the CRR and CR models in the internal and external validation sets (P = 0.264 and P = 0.084, respectively). CONCLUSIONS: Preoperative models based on clinical and CE-CT imaging features can be used to predict HCC with high Ki-67 expression accurately. However, radiomics cannot provide added value.

Beyond the Selectivity-Capacity Trade-Off: Ultrathin Carbon Nanoplates with Easily Accessible Ultramicropores for High-Efficiency Propylene/Propane Separation.

Rapid and highly efficient C3H6/C3H8 separation over porous carbons is seriously hindered by the trade-off effect between adsorption capacity and selectivity. Here, we report a new type of porous carbon nanoplate (CNP) featuring an ultrathin thickness of around 8 nm and easily accessible ultramicropores (approximately 5.0 Å). The ultrathin nature of the material allows a high accessibility of gas molecules into the interior transport channels, and ultramicropores magnify the difference in diffusion behavior between C3H6 and C3H8 molecules, together ensuring a remarkable C3H6/C3H8 separation performance. The CNPs show a high and steady C3H6 capacity of up to 3.03 mmol g-1 at 298 K during consecutive dynamic cycles, which is superior to that of the state-of-the-art porous carbons and even porous crystalline materials. In particular, the CNPs show a rapid gas diffusivity, which is 1000 times higher than that of conventional activated carbons. This research provides a promising design principle for addressing the selectivity-capacity trade-off for other types of adsorbent materials.

Boosting Selective Oxidation of Ethylene to Ethylene Glycol Assisted by In situ Generated H2 O2 from O2 Electroreduction.

Ethylene glycol is a useful organic compound and chemical intermediate for manufacturing various commodity chemicals of industrial importance. Nevertheless, the production of ethylene glycol in a green and safe manner is still a long-standing challenge. Here, we established an integrated, efficient pathway for oxidizing ethylene into ethylene glycol. Mesoporous carbon catalyst produces H2 O2 , and titanium silicalite-1 catalyst would subsequently oxidize ethylene into ethylene glycol with the in situ generated H2 O2 . This tandem route presents a remarkable activity, i.e., 86 % H2 O2 conversion with 99 % ethylene glycol selectivity and 51.48 mmol gecat -1 h-1 production rate at 0.4 V vs. reversible hydrogen electrode. Apart from generated H2 O2 as an oxidant, there exists ⋅OOH intermediate which could omit the step of absorbing and dissociating H2 O2 over titanium silicalite-1, showing faster reaction kinetics compared to the ex situ one. This work not only provides a new idea for yielding ethylene glycol but also demonstrates the superior of in situ generated H2 O2 in tandem route.

Prediction of microvascular invasion in HCC by a scoring model combining Gd-EOB-DTPA MRI and biochemical indicators.

OBJECTIVES: This study aimed to establish a reliable diagnostic scoring model for the preoperative prediction of microvascular invasion (MVI) in hepatocellular carcinoma (HCC) patients based on gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and biochemical indicators. METHODS: This retrospective study included 129 patients with HCC at our hospital from 2014 to 2020. Based on the intratumoral and peritumoral features on Gd-EOB-DTPA MRI and biochemical indicators, a scoring model was developed for preoperative prediction of MVI, and examined for diagnostic efficacy according to postoperative pathological results. The scoring model was further externally validated in an independent cohort of 63 HCC patients. RESULTS: Logistic regression analysis was performed to identify five parameters related to MVI, including maximum tumor diameter, peritumoral low intensity in the hepatobiliary phase, incomplete capsule, apparent diffusion coefficient (ADC), and [alkaline phosphatase (ALP) (U/L) + gamma-glutamyl transpeptidase (GGT) (U/L)] / lymphocyte count (× 109/L) ratio (AGLR). Based on these five parameters, a scoring model was developed, and the accuracy, sensitivity, specificity, PPV, and NPV in predicting MVI were 93.6%, 94.7%, 93.2%, 85.7%, and 97.6%, respectively, with a score > 8 set as the threshold. CONCLUSION: The scoring model based on Gd-EOB-DTPA MRI and biochemical indicators provides a reliable tool for preoperative prediction of MVI in HCC patients. KEY POINTS: • The scoring model based on Gd-EOB-DTPA MRI and biochemical indicators is practical for preoperative prediction of MVI in HCC patients. • AGLR is an independent risk factor for MVI. • The scoring model could help implement more appropriate interventions, potentially leading to precise and individualized treatments based on the biological characteristics of the tumor.

Self-Pillared Ultramicroporous Carbon Nanoplates for Selective Separation of CH4 /N2.

There is growing evidence that pillaring up a densely packed ultramicroporous two-dimensional (2D) structure is an effective strategy to reduce their internal diffusion. Reliable pillaring paradigms, however, is rather challenging. Here we report a one-pot multi-component sequential assembly method for the preparation of a new self-pillared 2D polymer and ultramicroporous carbon with integrated surface protrusions. The molecular level pillaring process is surprisingly fast, that is, in 10 min. The thickness of nanoplate edge and the density (roughness), angle as well as height of protrusions can be precisely tuned. Exemplified in coal bed methane purification/separation, this unique pillared 2D carbons exhibit a CH4 /N2 selectivity up to 24 at a low CH4 partial pressure and two orders of magnitude faster CH4 diffusion kinetics than the commercial carbon molecular sieves. This solution synthesis methodology is generalizable for creation and fine tuning of pillared 2D heterostructures.

Wiggling Mesopores Kinetically Amplify the Adsorptive Separation of Propylene/Propane.

Adsorptive separation is an appealing technology for propylene and propane separation; however, the challenge lies in the design of efficient adsorbents which can distinguish the two molecules having very similar properties. Here we report a kinetically amplified separation by creating wiggling mesopores in structurally robust carbon monoliths. The wiggling mesopores with alternating wide and narrow segments afford a surface area of 413 m2 g-1 and a tri-modal pore size distribution centered at 1.5, 4.2 and 6.6 nm, respectively. The synergistically kinetic and equilibrium effects were observed and quantitatively assessed, which together ensured a remarkable propylene/propane selectivity up to 39. This selectivity outperformed not only the available carbon adsorbents but also highly competitive among the dominated crystalline porous adsorbents. In addition, the wiggling mesoporous carbon adsorbent showed excellent dynamical separation stability, which ensured its great potential in practical molecular separations.

Effects of small nucleolar RNA SNORD44 on the proliferation, apoptosis and invasion of glioma cells.

To master the effect of small nucleolar RNA, SNORD44, on the proliferation, apoptosis and invasion of glioma cells and its relevant mechanism. SNORD44 and GAS5 expression in glioma tissues and cells was detected through qRT-PCR. Then, the glioma cell lines (U87 and U251) were divided into different groups with different treatments. Cell proliferation was determined by MTT assay, while the abilities of the cell migration and invasion were measured by wound-healing test and Transwell assay, respectively. Cell apoptosis were detected by flow cytometry and TUNEL assay. The expression of apoptosis proteins was quantified through Western blotting. Finally, the xenograft models were established on nude mice to investigate the effects of SNORD44 on the growth of glioma and the expressions of Ki67, MMP2 and MMP9 in vivo. SNORD44 and GAS5 were down-regulated in glioma tissues and cells in a positive correlation. Either SNORD44 or GAS5 overexpression decreased the proliferation, invasion and migration of U87 and U251 cells with the up-regulation of apoptosis rates, as well as the expressions of cleaved PARP, caspase 3, caspase 8 and caspase 9. Moreover, the in vivo experiment showed that overexpression of SNORD44 blocked the growth of glioma xenograft in nude mice accompanying with the inhibition of Ki67, MMP2 and MMP9 expressions. The combination overexpression of SNORD44 and GAS5 gained better inhibitory effects on glioma cells. Overexpression of SNORD44 and GAS5 activate the caspase-dependent apoptosis pathway to facilitate the apoptosis with the inhibited proliferation, invasion and migration of glioma cells.

Molecular-Based Design of Microporous Carbon Nanosheets.

Microporous carbons afford high surface areas, large pore volumes, and good conductivity, and are fascinating over a wide range of applications. Traditionally synthesized microporous carbon materials usually suffer from some limitations, such as poor accessibility and slow mass transport of molecules due to the micrometer-scale diffusion pathways and space confinement imposed by small pore sizes. Two-dimensional microporous carbon materials, denoted as microporous carbon nanosheets (MCNs), possess nanoscale thickness, which allows fast mass and heat transport along the z axis; thus overcoming the drawbacks of their bulk counterparts. Herein, recent breakthroughs in the synthetic strategies for MCNs are summarized. Three typical methods are discussed in detail with several examples: pyrolysis of organic precursors with 2D units, a templating method that uses wet chemistry, and the molten salt method. Among them, molecular-based assembly of MCNs in the liquid phase shows more controllable morphology, thickness, and pore size distribution. Finally, challenges in this research area are discussed to inspire future explorations.

Polyacrylonitrile-Derived Sponge-Like Micro/Macroporous Carbon for Selective CO2 Separation.

CO2 capture under a dynamical flow situation requires adsorbents possessing balanced proportion of macropores as diffusion path and micropores as adsorption reservoir. However, the construction of interconnected micro-/macropores structure coupled with abundant nitrogen species into one carbon skeleton remains a challenge. Here, we report a new approach to prepare sponge-like carbon with a well-developed micro-/macroporous structure and enriched nitrogen species through aqueous phase polymerization of acrylonitrile in the presence of graphene oxide. The tension stress caused by the uniform thermal shrinkage of polyacrylonitrile during the pyrolysis together with the favorable flexibility of graphene oxide sheets are responsible for the formation of the sponge-like morphology. The synergistic effect of micro-/macroporous framework and rich CO2 -philic site enables such carbon to decrease resistance to mass transfer and show high CO2 dynamic selectivity over N2 (454) and CH4 (11), as well as good CO2 capacity at 298 K under low CO2 partial pressure (0.17 bar, a typical CO2 partial pressure in flue gas). The above attributes make this porous carbon a promising candidate for CO2 capture from flue gas, methane sources and other relevant applications.

Thermoregulated Phase-Transition Synthesis of Two-Dimensional Carbon Nanoplates Rich in sp2 Carbon and Unimodal Ultramicropores for Kinetic Gas Separation.

The development of highly selective, chemically stable and moisture-resistant adsorbents is a key milestone for gas separation. Porous carbons featured with random orientation and cross-linking of turbostratic nanodomains usually have a wide distribution of micropores. Here we have developed a thermoregulated phase-transition-assisted synthesis of carbon nanoplates with more than 80 % sp2 carbon, unimodal ultramicropore and a controllable thickness. The thin structure allows oriented growth of carbon crystallites, and stacking of crystallites in nearly parallel orientation are responsible for the single size of the micropores. When used for gas separation from CH4 , carbon nanoplates exhibit high uptakes (5.2, 5.3 and 5.1 mmol g-1 ) and selectivities (7, 71 and 386) for CO2 , C2 H6 and C3 H8 under ambient conditions. The dynamic adsorption capacities are close to equilibrium uptakes of single components, further demonstrating superiority of carbon nanoplates in terms of selectivity and sorption kinetics.

Al2O3 Nanosheets Rich in Pentacoordinate Al(3+) Ions Stabilize Pt-Sn Clusters for Propane Dehydrogenation.

In heterogeneous catalysis, supports play a crucial role in modulating the geometric and electronic structure of the active metal phase for optimizing the catalytic performance. A γ-Al2O3 nanosheet that contains 27% pentacoordinate Al(3+) sites can nicely disperse and stabilize raft-like Pt-Sn clusters as a result of strong interactions between metal and support. Consequently, there are strong electronic interactions between the Pt and Sn atoms, resulting in an increase in the electron density of the Pt sites. When used in the propane dehydrogenation reaction, this catalyst displayed an excellent specific activity for propylene formation with >99% selectivity, and superior anti-coking and anti-sintering properties. Its exceptional ability to maintain the high activity and stability at ultrahigh space velocities further showed that the sheet construction of the catalyst facilitated the kinetic transfer process.

Selective formation of carbon-coated, metastable amorphous ZnSnO3 nanocubes containing mesopores for use as high-capacity lithium-ion battery.

Mesoporous and amorphous ZnSnO3 nanocubes of ~37 nm size coated with a thin porous carbon layer have been prepared using monodisperse ZnSn(OH)6 as the active precursor and low-temperature synthesized polydopamine as the carbon precursor. The small single nanocubes cross-link with each other to form a continuous conductive framework and interconnected porous channels with macropores of 74 nm width. Because of its multi-featured nanostructure, this material exhibits greatly enhanced integration of reversible alloying/de-alloying (i.e., transformation of Li(4.4)Sn and LiZn to Sn and Zn) and conversion (i.e., oxidation of Sn and Zn to ZnSnO3) reaction processes with an extremely high capacity of 1060 mA h g(-1) for up to 100 cycles. A high reversible capacity of 650 and 380 mA h g(-1) can also be delivered at rates of 2 and 3 A g(-1), respectively. This excellent electrochemical performance is attributed to the small particle size, well-developed mesoporosity, the amorphous nature of the ZnSnO3 and the continuous conductive framework produced by the interconnected carbon layers.

Confined nanospace pyrolysis for the fabrication of coaxial Fe3O4@C hollow particles with a penetrated mesochannel as a superior anode for Li-ion batteries.

In this study, a method is developed to fabricate Fe3O4@C particles with a coaxial and penetrated hollow mesochannel based on the concept of "confined nanospace pyrolysis". The synthesis involves the production of a polydopamine coating followed by a silica coating on a rod-shaped ß-FeOOH nanoparticle, and subsequent treatment by using confined nanospace pyrolysis and silica removal procedures. Typical coaxial hollow Fe3O4@C possesses a rice-grain morphology and mesoporous structure with a large specific surface area, as well as a continuous and flexible carbon shell. Electrochemical tests reveal that the hollow Fe3O4@C with an open-ended nanostructure delivers a high specific capacity (ca. 864 mA h g(-1) at 1 A g(-1)), excellent rate capability with a capacity of about 582 mA h g(-1) at 2 A g(-1), and a high Coulombic efficiency (>97%). The excellent electrochemical performance benefits from the hollow cavity with an inner diameter of 18 nm and a flexible carbon shell that can accommodate the volume change of the Fe3O4 during the lithium insertion/extraction processes as well as the large specific surface area and open inner cavity to facilitate the rapid diffusion of lithium ions from electrolyte to active material. This fabrication strategy can be used to generate a hollow or porous metal oxide structure for high-performance Li-ion batteries.

Multiscale Tunable Nanorings Based on Bi-Component Micellar-Configuration-Transformation Induced by Hydrophobicity.

Ringy nanostructures are amazing materials, displaying unique optical, magnetic, and electronic properties highly related to their dimensions. A strategy capable of continuously tailoring the diameter of nanorings is the key to elucidating their structure-function relationship. Herein, a method of bi-component micellar-configuration-transformation induced by hydrophobicity for the synthesis of nanorings with diameters ranging from submicron (≈143 nm) to micron (≈4.8 µm) and their carbonaceous analogs is established. Remarkably, the nanorings fabricated with this liquid phase strategy achieve the record for the largest diameter span. Through varying the molecular lengths of fatty alcohols and copolymers, shortening the molecular length of fatty alcohol can swell the primary micelles, improve the exposure of hydrophobic component and boost the assembly kinetics for ultra-large nanorings is shown here. On the other hand, shortening the molecular length of the copolymer will give rise to ultra-small nanorings by reducing the size of primary micelles and shortening the assembly time. When assembling the nanorings into monolayer arrays and then depositing Au, such substrate displays enhanced surface-enhanced Raman scattering (SERS) performance. This research develops a facile method for the controllable synthesis of ringy materials with multiscale tunable diameters and may inspire more interesting applications in physics, optical, and sensors.

Unraveling the Role of Li and Mg Substitution in Layered Sodium Oxide Cathodes for Sodium-Ion Batteries.

Substituting electrochemically active elements such as Li and Mg in P2-type layered sodium oxide is an effective strategy for developing competitive cathode materials for sodium-ion batteries. However, the lack of atomic-level understanding regarding the distribution of substitution positions complicates the comprehension of the roles of substituting atoms and the mechanism of sodium-ion intercalation. In this study, we identified the stable configurations of Na in Na0.75Ni0.3Mn0.7O2 and Na0.75Li0.15Mg0.05Ni0.1Mn0.7O2 materials using the site exclusion method. Through simulating the complete charging process for both materials, the structure evolution of the cathodes during the cycling and the impact of the partial substitution of Ni elements by Li and Mg atoms were comprehensively elucidated. Our findings revealed that Mg atoms effectively regulate the distribution of forces within the materials, essentially serving as supportive pillars within the cathode. Meanwhile, Li atoms efficiently mitigated electron localization, consequently diminishing volume fluctuations during the charging process. More importantly, the substitution with Li and Mg atoms could synergistically reduce the interaction between transition metals and sodium ions, thereby reducing the diffusion energy barrier of Na ions. This study not only enhances the comprehension of substituted metal atoms in P2 layered oxides but also offers new insights for the development of sodium-ion cathode materials.

Revealing an Extended Adsorption/Insertion-Filling Sodium Storage Mechanism in Petroleum Coke-Derived Amorphous Carbon.

Amorphous carbon holds great promise as anode material for sodium-ion batteries due to its cost-effectiveness and good performance. However, its sodium storage mechanism, particularly the insertion process and origin of plateau capacity, remains controversial. Here, an extended adsorption/insertion-filling sodium storage mechanism is proposed using petroleum coke-derived amorphous carbon as a multi-microcrystalline model. Combining in situ X-ray diffraction, in situ Raman, theoretical calculations, and neutron scattering, the effective storage form and location of sodium ions in amorphous carbon are revealed. The sodium adsorption at defect sites leads to a high-potential sloping capacity. The sodium insertion process occurs in both the pseudo-graphite phase (d002 > 0.370 nm) and graphite-like phase (0.345 ≤ d002 < 0.370 nm) rather than the graphite phase, contributing to low-potential sloping capacity. The sodium filling into accessible closed pores forms quasi-metallic sodium clusters, contributing to plateau capacity. The threshold of the effective interlayer spacing for sodium insertion is extended to 0.345 nm, breaking the consensus of insertion interlayer threshold and enhancing understanding of closed pore filling. The extended adsorption/insertion-filling mechanism explains the sodium storage behavior of amorphous carbon with different microstructures, providing theoretical guidance for the rational design of high-performance amorphous carbon anodes.

Switchable transport strategy to deposit active Fe/Fe3C cores into hollow microporous carbons for efficient chromium removal.

Magnetic hollow structures with microporous shell and highly dispersed active cores (Fe/Fe3 C nanoparticles) are rationally designed and fabricated by solution-phase switchable transport of active iron species combined with a solid-state thermolysis technique, thus allowing selective encapsulation of functional Fe/Fe3 C nanoparticles in the interior cavity. These engineered functional materials show high loading (≈54 wt%) of Fe, excellent chromium removal capability (100 mg g(-1)), fast adsorption rate (8766 mL mg(-1) h(-1)), and easy magnetic separation property (63.25 emu g(-1)). During the adsorption process, the internal highly dispersed Fe/Fe3 C nanoparticles supply a driving force for facilitating Cr(VI) diffusion inward, thus improving the adsorption rate and the adsorption capacity. At the same time, the external microporous carbon shell can also efficiently trap guest Cr(VI) ions and protect Fe/Fe3 C nanoparticles from corrosion and subsequent leaching problems.