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A series of MXene/MnCo2O4.5 nanocomposites was successfully prepared by hydrothermal, ice crystal template and physical blend methods, respectively. Various characterizations indicated that hydrothermal method could successfully loaded MnCo2O4.5 nanoparticles on the surface of MXene nanosheets to obtain MMC-W nanocomposites with 3D flower-like structure, which could give MMC-W large specific surface area. The HTD temperature and decomposition heat of AP with adding 2.0 wt% MMC-W could significantly decrease to 304.7 °C and increase to 1310.9 J g-1, respectively. The lowest decomposition temperature (286.1 °C) and the highest heat release (1427.6 J g-1) of AP could be obtained by adding 8.0 wt% and 4.0 wt% of MMC-W, respectively. Moreover, MMC-W (2.0 wt%) could also significantly reduce the Ea of pure AP by 118.3 kJ mol-1 and increase the k value for AP by 11.2 times. The excellent catalytic performance of MMC-W was owing to the synergistic effect of nano-sized MnCo2O4.5 and MXene nanosheets. Owing to its high catalytic activity, MMC-W would be used as an excellent catalyst for ameliorating AP decomposition and supply an idea for the preparation of novel metal oxide nanoparticles.

Engineering the electronic properties of catalysts to target intermediate adsorption energy as well as harvest high selectivity represents a promising strategy to design advanced electrocatalysts for efficient CO2 electroreduction. Herein, a synergistically tuning on the electronic structure of the CdSe nanorods is proposed for boosting electrochemical reduction of CO2. The synergy of Ag doping coupled with Se vacancies tuned the electronic structure of the CdSe nanorods, which shows the metalloid characterization and thereby the accelerated electron transfer of CO2 electroreduction. Operando synchrotron radiation Fourier transform infrared spectroscopy and theoretical simulation revealed that the Ag doping and Se vacancies accelerated the CO2 activation process and lowered the energy barrier for the conversion from CO2 to *COOH; as a result, the performance of CO2 electroreduction was enhanced. The as-obtained metalloid Ag-doped CdSe nanorods exhibited a 2.7-fold increment in current density and 1.9-fold Faradaic efficiency of CO than pristine CdSe nanorod.

Herein, 3D alumina-doped magnesium oxide (Al2O3/MgO) aerogels were successfully prepared by a simple lyophilization–calcination method for the uranium (U(VI)) elimination from wastewater. Various batch experiments were used to testify that Al2O3/MgO aerogels exhibited remarkable removal performance for U(VI), especially Al2O3/MgO aerogels with Al2O3/MgO molar ratios of 1 : 1 (Al/Mg-3). Results showed that Al/Mg-3 could quickly reach the adsorption equilibrium within the contact time of 100 min, while the adsorption capacity of Al/Mg-3 for U(VI) could reach as high as 1046.9 mg g−1 at pH 6.0. The selectivity of Al/Mg-3 for U(VI) proved that Al/Mg-3 could be used to remove U(VI) from wastewater. The adsorption efficiency of Al/Mg-3 for U(VI) could still retain more than 92.5% after five cycles. Furthermore, the continuous U(VI) separation test results showed that the adsorption equilibrium time and adsorption efficiency of Al/Mg-3 could decrease to 40 min and increase to 99.7%, respectively. This work demonstrated that the remarkable U(VI) removal performance of Al/Mg-3 could make it an effective and reusable material for the adsorption of U(VI) from U(VI)-contained wastewater.

In this study, mineral-element migration upon pyrolysis and quantitative prediction of volatiles were investigated by laser induced breakdown spectroscopy (LIBS) for three characteristic types of coal. KBr was used to polymerize coal or char into a pellet. High percentage of KBr provided a good environment for forming plasmas of stable emissions with relatively high electron excitation temperature and electron density, due to the suppression of the laser-ablation induced pyrolysis of volatile matter. With the increasing pyrolysis temperature, char atomic emissions were greatly increased, which is thought to be related to mineral-element reloading in the char surface upon pyrolysis. Divergence of intensity ratios Ichar/Icoal of Fe/Ca/Mg between high-volatile and low-volatile coal indicates that the Fe/Ca/Mg-containing minerals from volatiles may change their existing forms upon pyrolysis, which can easily trigger more intensive emissions. These findings indicate that LIBS can offer a powerful tool for studying mineral-element migration and contribute to improving numerical simulations of coal pyrolysis and combustion. Finally, multiple linear regression (MLR) and artificial neural network (ANN) methods were applied for quantification of volatile content. MLR models with R2 > 0.977 for single-rank coal samples and ANN models with R2 = 0.991 for all samples were achieved, which provide an accurate and reliable method for industrial coal quality evaluations.

A novel oxidized MXene-supported MCo2O4 (oxidized MXene/MCo2O4, M = Mn, Zn, Cu and Co) nanocomposite was successfully synthesized through a facile hydrothermal assisted calcination method. Various characterization results indicated that MCo2O4 nanoparticles were successfully formed in situ on MXene nanosheets, which effectively reduce the aggregation of nanoparticles and remarkably improve the specific surface area, especially MZC (203.5 m2 g−1). Among the oxidized MXene/MCo2O4 nanocomposites, oxidized MXene/ZnCo2O4 (MZC) enormously ameliorated the performance of AP decomposition. With adding MZC (2.0 wt%), the high-temperature decomposition (HTD) temperature of AP could significantly decrease to 297.1 °C, while the decomposition heat could increase to 1409.6 J g−1, respectively. The apparent activation energy of AP decomposition decreased from 209.6 kJ mol−1 (pure AP) to 104.5 kJ mol−1 (AP mixed with MZC). The excellent catalytic performance of MZC might be due to the synergistic effect of MXene nanosheets and ZnCo2O4 nanoparticles. It could be foreseen that MZC would be an excellent material for optimizing AP decomposition and would supply an idea for the development of new catalyst materials.

High-entropy alloys (HEAs), which are defined as near-equimolar alloys of five or more elements, are attracting ever increasing attention because of the unique properties in a variety of applicatio...

Mesoporous ZrO2/SBA-15 materials were prepared for the first time by a one-step method using ZrO2 as zirconium source and their uranium (U(VI)) adsorption behavior were studied. The influence of ZrO2 content on the structure, morphology and hydrothermal stability of the obtained ZrO2/SBA-15 was investigated. It was found that the structural order of ZrO2/SBA-15 decreased with increasing ZrO2 content. The hydrothermal stability of SBA-15 was improved by loading of ZrO2. Furthermore, the effects of pH, initial U(VI) concentration, contact time, temperature and ZrO2 content on the U(VI) adsorption capacity were studied. The results demonstrated that the U(VI) adsorption capacity decreased with increasing ZrO2 content and temperature. The adsorption process was found to be well fitted to the Langmuir and pseudo-second-order model. The calculated maximum adsorption capacities were 326 and 294 mg·g−1 for 0.4ZrO2/SBA-15 and 0.8ZrO2/SBA-15 samples at 283 K, respectively. Furthermore, the analysis of thermodynamic parameters (ΔG, ΔH, and ΔS) revealed that the process of U(VI) adsorption onto ZrO2/SBA-15 was feasible, spontaneous and exothermic.

Photocatalytic degradation of organic pollutants has become a hot research topic because of its low energy consumption and environmental-friendly characteristics. Bismuth oxide (Bi2O3) nanocrystals with a bandgap ranging from 2.0 eV to 2.8 eV have attracted increasing attention due to high activity of photodegradation of organic pollutants by utilizing visible light. Though several methods have been developed to prepare Bi2O3-based semiconductor materials over recent years, it is still difficult to prepare highly active Bi2O3 catalysts in large scale with a simple method. Therefore, developing simple and feasible methods for the preparation of Bi2O3 nanocrystals in large scale is important for the potential applications in industrial wastewater treatment. In this work, we successfully prepared porous Bi2O3 in large scale via etching commercial BiSn powders, followed by thermal treatment with air. The acquired porous Bi2O3 exhibited excellent activity and stability in photocatalytic degradation of methylene blue. Further investigation of the mechanism witnessed that the suitable band structure of porous Bi2O3 allowed the generation of reactive oxygen species, such as O2−· and ·OH, which effectively degraded MB.

Photosensitizers with charge-separated excited states are commonly introduced into photocatalytic systems to accomplish photon-to-electron transformation. Unfortunately, the photosensitizers in cur...

It is a challenge to fabricate three-dimensional carbon aerogels based on natural renewable resources with stability, flexibility, and versatility. Here, an ultralight, elastic, and hydrophobic mul...

As a promising candidate for CO2 electroreduction, metal chalcogenides suffer from limited carrier density, which hampers the electron transport of electrocatalysts and activation of CO2. Herein, we have modified In2S3 nanosheets by in situ forming metallic In nanoparticles for enhanced CO2 electroreduction. The In-In2S3 hybrid nanosheets exhibited a remarkable geometrical current density of 70.3 mA cm-2 at -1.1 V vs. RHE, with 62.1 mA cm-2 for the carbonaceous product. The faradaic efficiency of the In-In2S3 hybrid nanosheets for the carbonaceous product reached 90% at -1.0 V vs. RHE, including 76% for formate production and 14% for CO production. The mechanistic study revealed that the improved performance by forming In nanoparticles on In2S3 nanosheets originated from the increased carrier density of the electrocatalysts and the decreased work function, which benefited the CO2 activation.

High-entropy alloys (HEAs) have exhibited large potential to serve as excellent heterogeneous catalysts in a variety of reactions. Although several synthetic procedures have been reported, developing novel routes to facilely prepare HEA-based catalysts is still urgently desired, especially for large-scale preparation. Herein, we successfully prepared porous HEAs by directly etching low-cost, accessible, and commercial HEA powders in an acid aqueous solution at room temperature. Porous HEA CrMnFeCoNi (CMFCN-4) was synthesized from commercial CrMnFeCoNi powder (the Cantor alloy). Surprisingly, the contents of metallic elements in CMFCN-4 were all maintained at ca. 20% due to a kinetically controlled etching process. In the hydrogenation of p-nitrophenol, porous CMFCN-4 exhibited remarkable catalytic activity by converting >90% of p-nitrophenol into p-aminophenol within 30 min at 25 °C. The activation energy for CMFCN-4 was as low as 31.8 kJ mol−1, even comparable to that for noble-metal based catalysts. Moreover, CMFCN-4 also revealed excellent catalytic stability by preserving nearly 100% of the initial catalytic activity after five successive reaction rounds. Derived from porous structures, the high surface area and exposed high-index facets with terraces contributed to the excellent catalytic performance of CMFCN-4. This work not only provides a highly active and stable HEA-based catalyst, but also opens up a new avenue to the facile and large-scale synthesis of porous HEAs by directly etching commercial HEA powders.

Highlights A surface oxygen-injection strategy is proposed to synergistically modulate the electronic structure of the SnS2 nanosheets, thereby regulating the oxophilicity of the catalyst surface.The surface oxygen doping facilitates the CO2 activation and enhances the affinity for HCOO* species.The oxygen-injection SnS2 nanosheets exhibit a remarkable Faradaic efficiency of 91.6% for carbonaceous products with a current density of 24.1 mA cm−2 at -0.9 V vs RHE. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00703-6., Surface chemistry modification represents a promising strategy to tailor the adsorption and activation of reaction intermediates for enhancing activity. Herein, we designed a surface oxygen-injection strategy to tune the electronic structure of SnS2 nanosheets, which showed effectively enhanced electrocatalytic activity and selectivity of CO2 reduction to formate and syngas (CO and H2). The oxygen-injection SnS2 nanosheets exhibit a remarkable Faradaic efficiency of 91.6% for carbonaceous products with a current density of 24.1 mA cm−2 at −0.9 V vs RHE, including 83.2% for formate production and 16.5% for syngas with the CO/H2 ratio of 1:1. By operando X-ray absorption spectroscopy, we unravel the in situ surface oxygen doping into the matrix during reaction, thereby optimizing the Sn local electronic states. Operando synchrotron radiation infrared spectroscopy along with theoretical calculations further reveals that the surface oxygen doping facilitated the CO2 activation and enhanced the affinity for HCOO* species. This result demonstrates the potential strategy of surface oxygen injection for the rational design of advanced catalysts for CO2 electroreduction. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00703-6.

In order to protect environment and save uranium resources, it was necessary to find a highly efficient adsorbent for uranium recovery from wastewater. In this work, we used a freeze-drying-calcination method to synthesize HAP aerogel to effectively remove uranium. Compared with commercially available nano-hydroxyapatite, HAP aerogel presented better adsorption performance. This was because the as-prepared HAP aerogel presented continuous porous structure, which could provide more active sites for the adsorption to uranium. The uranium removal efficiency of HAP aerogel arrived 99.4% within 10 min and the maximum adsorption capacity was up to 2087.6 mg g−1 at pH = 4.0 and 298 K. In addition, the immobilization of uranium on HAP aerogel was chemisorption, which was probably due to adsorption, dissolution-precipitation and ions exchange. These results indicated that the as-prepared HAP aerogel could be widely used as a high efficiency and potential adsorbent for the treatment of uranium-containing wastewater in the future.

A novel nanospherical hydrous titanium oxide adsorbent (hydrous titanium oxide-immobilized bovine serum albumin nanospheres, HTO-BSA-NSs) was prepared by immobilizing HTOs with a manipulated molecular mass and number of active sites for uranium on the surface of BSA-NSs. The adsorption performances of HTO-BSA-NSs were investigated in spiked natural seawater with extra 8 ppm uranium. The results demonstrated that HTO-BSA-NSs are capable of uranium capture from a complex aqueous matrix with a low uranium concentration. Meanwhile, the microbial stability of HTO-BSA-NSs in sterilized natural seawater with Marinobacter sp. was investigated and observed through an optical microscope and TEM, revealing that the wrapped HTOs could protect the BSA-NSs from the decomposition of microorganisms, and the structure and functional groups of HTO-BSA-NSs remain stable compared with the BSA-NSs. In addition, the uranium adsorption mechanism of HTO-BSA-NSs is mainly recognized as dehydrated complexation, which was concluded from characterization analysis, adsorption model fitting, and theoretical calculations based on density functional theory. The remarkable uranium adsorption performance and microbial stability of HTO-BSA-NSs indicated that they have the potential to be a low-cost and environmentally friendly adsorbent for uranium extraction from complex environments such as seawater or uranium-containing industrial wastewater.

This research investigated the emission and evolution characteristics of fuel-N during the O2/H2O combustion process of a typical bituminous coal (Shenhua). To avoid the catalytic interference of alkali metal salts, the demineralized coal obtained from the raw coal sample was employed for the investigation in this research. The effects of reaction temperature (Tr) and H2O concentration, which were two vital factors affecting coal combustion characteristics, on the emission characteristics of fuel-N during the combustion process were also taken into consideration. Isothermal combustion tests performed under different O2/H2O conditions (Tr: 1073 and 1473 K; O2: 30%; H2O: 0, 3.5, 8.5, 15, 20, and 30 vol %) indicated that relatively high concentrations of N2O, HCN, and NH3 were measured in the O2/H2O combustion of the coal sample. With the increase of Tr and H2O concentration, more fuel-N would be released in the devolatilization/volatile oxidation stage of the reaction. The X-ray photoelectron spectroscopy r...

Uranium is important in the nuclear fuel cycle as both as an energy source and as radioactive waste. Herein, activated carbon (AC) prepared from waste cigarette filters by convenient carbonization and functionalization was chosen as the raw materials for radionuclides adsorption. Batch adsorption experiments showed that AC presented comparable UO22+ adsorption capacity (106 mg g−1) and very outstanding selectivity. The adsorption process accorded with Langmuir model and the pseudo-second-order kinetics model well. This work combines the waste cigarette filters with the radioactive nuclear treatment materials, which may provide a new strategy for the future treatment of waste cigarette butts.

Zircon ceramics (ZrSiO4) are promising candidates for actinide immobilization. Here, a series of Zr1-xNdxSiO4-x/2 (x = 0, 0.02, 0.20, and 1.0) ceramics are prepared to study the effects of phase evolution and acidity on the chemical durability of ZrSiO4-based nuclear waste forms. The results show that the chemical stability of the single-phase ZrSiO4 sample is better than that of the biphasic Zr0.8Nd0.2SiO3.9 sample due to the existence of a secondary highly soluble phase (Nd2Si2O7), which increases the contact area with leachate. The normalized release rates of both zirconium (Zr) and neodymium (Nd) in the Zr1-xNdxSiO4-x/2 ceramic waste forms increase with increasing Nd loading and acid concentration. LRZr in ZrSiO4 ceramics and LRNd in Zr0.98Nd0.02SiO3.99 ceramics are the lowest, while LRZr and LRNd reach the highest values in the Zr0.8Nd0.2SiO3.9 and Nd2Si2O7 ceramics, respectively. The normalized release rates of Zr are lower than those of Nd due to the difference in the energies of their bonds with oxygen atoms. Moreover, the changes in the surfaces of the leached ceramics are consistent with their leaching results.

Carbon aerogels with biomimetic structures have shown excellent physicochemical properties and brought great potential applications to a wide range of fields. The utilization of renewable resources as the carbon precursors offers a low-cost and scalable way to fabricate biomimetic carbon aerogels with intriguing properties such as ultralight weight, superelasticity, and high conductivity. Inspired by the unique hierarchical mineral bridge structure of Thalia dealbata stem, we fabricated an ultralight, superelastic, highly conductive carbon aerogel (KGA) by using konjac glucomannan and graphene oxide as the carbon precursors. The unique mineral-bridged layered structure not only endows the carbon aerogel with a low density of 4.2 mg cm–3 but also a high electrical conductivity (12.9 S m–1). In addition, the carbon aerogel also exhibits a superelastic property of 80% maximal strain and no obvious degradation after 1000 cycles of compression. We demonstrated that this Thalia dealbata inspired carbon aerogel ...

Amorphous calcium carbonate/chitosan (ACC/CS) nanocomposite films containing Mg-ACC (0–100 wt%) are prepared by simple natural evaporation-induced assembly. The influence of Mg-ACC content on the mechanical properties as well as cross-section of ACC-CS nanocomposite films were systematically investigated. The nanocomposite films exhibit an excellent mechanical property at Mg-ACC contents of 80 wt% compared to ordinary calcium carbonate/chitosan composites. With content of Mg-ACC increasing, the mechanical properties of ACC-CS nanocomposite films were further increased, reaching a maximum when the content of Mg-ACC to 80 wt%. Strength and Young's modulus of the 80 wt% ACC-CS nanocomposite film reach 121.67 MPa and 31.96 GPa, respectively, which is 2.3 and 5.1 times higher than that of the pure CS film. After undergoing Mg-ACC crystal transformation when the Mg-ACC content is greater than 80 wt%, the smooth structure was transformed into crystal-like agglomerates, which deteriorates mechanical properties. Furthermore, the as-prepared nanocomposite films show excellent hydrophobicity and high biocompatibilities for boosting the growth of Cell-293T. In addition, we also proposed a physical model for the dispersion of Mg-ACC in CS matrix, which could better explain the enhancement of the mechanical properties of nanocomposite films. The above results provide a comprehensive understanding of the development of high-performance bionic nanocomposites loaded with high nanofillers.

The reduction of U(VI) to U(IV) in wastewater by semiconductor photocatalysis has become a new highly efficient and low-cost method for U(VI) removal. However, due to the weak absorption of visible light led by wide band gap and low carrier utilization rate resulted from the severe electron-holes recombination, the photoreduction performance of U(VI) is limited. Herein, the Ti vacancies and doped Fe atoms were simultaneously introduced into TiO2 nanosheet (labeled as 4%Fe-Ti1−xO2) as a highly active and stable catalysis for U(VI) photoreduction. Without adding any hole sacrifice agent, 4%Fe-Ti1−xO2 nanosheets achieved 99.7% removal efficiency for U(VI) within 120 min. And the 92.1% removal efficiency of U(VI) via 4%Fe-Ti1−xO2 nanosheets was still maintained after 5 cycles. Moreover, 4%Fe-Ti1−xO2 exhibited dramatic removal rate, 81.6% U(VI) in the solution was removed in 10 min. Further study on the mechanism showed that simultaneously introducing the Ti vacancies and doped Fe atoms in 4%Fe-Ti1−xO2 nanosheets improved the visible light utilization and decreased the recombination of photogenerated electron-hole pairs, contributing to the highly efficiency removal of U(VI).

Manganese dioxide-loaded mesoporous SBA-15 silica (MnO2/SBA-15) composites with short pore length were aprepared for the first time by simply immersing SBA-15 into a KMnO4 and MnCl2 mixed solution. Adsorption of Sr2+ from aqueous solution by using the MnO2/SBA-15 was investigated by varying the pH, contact time, initial Sr2+ concentration, MnO2 content and temperature. The adsorption process was rapid during the first 40 min and reached equilibrium in 120 min. The Sr2+ adsorption capacity increased with increasing pH, MnO2 content and temperature, and the adsorption capacity of SBA-15 was significantly improved by the loading of MnO2. Moreover, the experimental adsorption data were analyzed using different equilibrium isotherm, kinetic and thermodynamic models. The results showed that the isotherm data were well-described by the Langmuir model. The maximum Sr2+ adsorption capacity was determined to be 75.1 mg g−1 at 283 K based on the Langmuir model. The analyzed kinetic data indicated that the Sr2+ adsorption process was well fitted by the pseudo-second order model. Furthermore, the thermodynamic parameters of adsorption were also determined from the equilibrium constant values obtained at different temperatures. The results suggested that the adsorption process was spontaneous and endothermic, and the overall mechanism of Sr2+ adsorption was a combination of physical and chemical processes.

How to efficiently treat radioactive uranium-containing nuclear wastewater is one of the significant challenges to ensure the safety of nuclear technology and to avoid environmental pollution. Here we firstly prepare the metal-free 2D/2D C3N5/GO nanosheets, and customize a type-II heterojunction based on the band bending theory to achieve enhanced uranium extraction capacity via synergistic adsorption photoreduction engineering. The structure of C3N5 is explained by electron energy loss spectroscopy and synchrotron-based near-edge X-ray absorption fine structure. And C3N5 with larger π-conjugated structure expands the light response range to 747 nm, which is about 1.67 times that of C3N4. Further, we also use density functional theory to prove the existence of alternating energy levels so that photogenerated electrons could be continuously injected into the surface of GO to ensure the effective separation of electron-hole pairs and increase the material activity. The results show that the removal ratio of uranium by 2D/2D C3N5/GO heterojunction is achieved as high as 96.1% even at a low uranium concentration of 10 ppm, and reached 93.4% after exposure to gamma-ray. This work will lay a foundation for customizing the energy band structure of nonmetal-based 2D/2D nanohybrids and enriching uranium-containing wastewater through adsorption photoreduction engineering in the future.

Uranium is a critical resource in the nuclear fuel cycle and also a global environmental pollutant with dual effects of radioactivity and chemical toxicity. To ensure the sustainability of environment while meeting future energy needs, reducing soluble U(VI) to relatively immovable U(IV) through photocatalytic technology is an effective strategy to achieve these goals. Here we firstly reported a novel C3N5/reduced graphene oxide (C3N5/RGO) aerogel photocatalyst with 3D macroscopic morphology, and further proved that it is formed form a microscopic 2D/2D nanosheet Mott Schottky heterostructure. The macroscopic 3D morphology of C3N5/RGO aerogel was effective in avoiding the rate-determination step in the uranium enrichment process and the secondary pollution of the environment caused by nanomaterials. The microscopic 2D/2D Mott Schottky heterojunction effectively reduced the electron/hole recombination on the semiconductor surface, thus improving the photocatalytic quantum efficiency. Notably, the U(VI) removal ratio of 3D C3N5/RGO aerogel reached up to 94.9% in the wastewater containing organic matter systems, and it was barely affected by the impurity ions (The content is reached 10 times) and the nuclear radiation (Up to 200 KGy). It is believed that 3D C3N5/RGO aerogel provides a viable solution to treating the wastewater with nuclear radioactivity.

Fuel-rich/lean combustion is considered as a novel combustion technology due to its enhanced ignition performance and low NOx emissions. To further improve the poor performance of large-proportion semicoke and bituminous coal blended combustion and reduce NOx emissions, under a bias concentration ratio (BCR) of 2:1, an addition of bluff bodies at the fuel-rich side is proposed to numerically and experimentally investigate the turbulence-chemistry interaction behaviours of the fuel-rich/lean combustion regime in a 0.3 kW pilot-scale bias combustion furnace for various bluff body blockage ratios (BR = 0%, 11% and 21%). The results show that, increasing the blockage ratio evidently shortens the ignition delay time and burnout time of bituminous coal and semicoke, and the promotive effect of triangular bluff-body (BR = 21%) is greater. The turbulent Damkohler number Dat maximums decrease from 194 to 113 with increasing BR, denoting the regime is traditional combustion mode controlled by mixing. On the fuel-rich side, a local homogeneous MILD combustion zone (Dat

Artificial nacre-like konjac glucomannan-Montmorillonite (KGM-MTM) composite films with ‘brick and mortar’ microstructures have been fabricated based on using KGM-MTM hybrid nanosheets as building blocks. In the designed fabrication procedure, we assembled hybrid building blocks with a thin layer of KGM coating on the MTM nanosheets to form KGM-MTM composite film via vacuum filtration. The nacre-like microstructures enhanced the light transmission performance and mechanical properties (Tensile strength: 116 MPa) of KGM-MTM composite films. Additionally, Ag nanoparticles (Ag NPs) can be incorporated into the layered structures of KGM-MTM composite films via an in situ reduced method. It was found that KGM-MTM-Ag composite films significantly suppress bacterial growth, which makes them potentially applicable as antimicrobial films in the biomedical field.

Heteroatom doped carbon originated from natural and renewable biomass has recently attracted tremendous attention related to electrode material of supercapacitors. Herein, we reported a practical and facile strategy to synthesize Mn-doped N-containing carbon materials based on collagen waste obtained from leather processing for supercapacitors, and this method was applicable to most metals. Mn-doped N-containing carbon was fabricated primarily by chelating metal ions with bayberry tannin immobilized collagen fiber, followed by a carbonization treatment. The as-prepared Mn-doped N-containing carbon material exhibited a high specific capacitance (272.62 F g−1 at the current density of 1.0 A g−1), high rate capability (72.21% capacitance retention with increasing current density from 1 to 20 A g−1), and after 6000 cycles remained 81.4%. Especially, it showed favorable thermal stability under extreme conditions (264.9 F g−1 and 262.65 F g−1 at 60 °C and 0 °C water bath under the current density of 1 A g−1, respectively). The results indicated that Mn-doped N-containing carbon was a practically potential electrode material for supercapacitors.

The highly efficient separation of radionuclides by the adsorbent with favorable ability is a compelling need with the development of the nuclear industry. In this paper, we chose fungus hypha as the skeleton, coated with a layer of two-dimensional graphene oxide sheets, and pyrolyzed as a fungal hyphae/graphene oxide aerogel for the application in uranium ions (U(VI)) removal. The macroscopically light fungus hypha and the reduced graphene oxide aerogel had a three-dimensional structure with an excellent capability on U(VI) removal (288.42 mg/g), attributed to its large specific surface area (894 m2/g) and abundant functional groups. In addition, the material also had a good recyclability through filtration and freeze-drying, respectively. We expected that the low cost and environmental-friendly aerogel would give some dominance in the field of the environment.

As an effective way to obtain solar energy and separate the soluble contaminants from water, solar-driven interfacial evaporation is used in desalination, wastewater treatment, electricity generation, and domestic water heating system. Herein, we demonstrate a monolithic sponge with three-dimensional porous structure as the solar-energy evaporator, which is composed of hydrophilic polymer (Konjac Glucomannan, KGM) and solar absorbent (reduced graphene oxide, rGO). Under one sun irradiation, the sponge achieves a rapid evaporation rate (1.60 kg m−2 h−1) and high interfacial water evaporation efficiency (92 %) due to its good absorption, photothermal, thermal insulation, and fast water transport properties. Meanwhile, the concentrations of radioactive elements (strontium, cesium, and uranium) in wastewater dropped from grams to micrograms after purification, even under radiation and acidic conditions. Additionally, the durability and repeatability of the sponge also have been verified. The results showed that solar-driven interfacial evaporation can effectively treat radioactive wastewater and enrich various radionuclides in a more energy-saving manner.

SiO2@TiO2 yolk@shell hollow nanospheres (STNSs) is considered as an outstanding photocatalyst due to its tunable structure and composition. Based on this point, we present an unprecedentedly excellent photocatalytic property of STNSs toward tannic acid via a Fe-N co-doped strategy. Their morphologies, compositions, structure and properties are characterized. The Fe-N co-doped STNSs formed good hollow yolk@shell structure. The results show that the energy gap of the composites can be downgraded to 2.82 eV (pure TiO2 = 3.2 eV). Photocatalytic degradation of tannic acid (TA, 30 mg L−1) under visible light (380 nm OH and O2− with a strong oxidizing property. Therefore this approach works is much desired for radioactive organic wastewater photocatalytic degradation.

In this paper, a biological assembly method was used to fix carbon nanotubes (CNTs) onto fungal hyphae (FH) to prepare sphere FH/CNTs composite as a versatile adsorbent for water pollution control. Physico-chemical characterization results showed that FH/CNTs composites had a wire stacking surface morphology, showed a typical diffraction peak of CNTs, was rich in functional groups, and was negatively charged under pH 3 to 10. Adsorptions of uranium (U(VI)), anionic (Congo red (CR)) and cationic (methyl violet (MV)) dyes under various conditions were investigated to elucidate their adsorption performances and mechanisms. Results showed that the composites could efficiently remove U(VI)), CR and MV from solutions. For example, the maximum adsorption amounts of FH/CNTs composites for U(VI), CR and MV reached 187.26, 43.99 and 20.89 mg/g, respectively. The adsorption process was fitted better by pseudo-second order model, while both of Langmuir and Freunlich models were well fitted to the adsorption isotherms for these pollutants. Moreover, the composites could be easily separated after adsorption and efficiently reused. Thus FH was an efficient platform for the assembly of CNTs, and the as-prepared FH/CNTs composites had the potential application in water pollution control.

We have demonstrated there is a significant intermolecular interaction between GO and KGM that results from hydrogen bonding and physical cross-linking by studying the rheological properties of a graphene oxide/konjac glucomannan (GO/KGM) solution. When the addition of GO was 5%, the storage modulus (G') and loss modulus (G″) were only improved by 0.25%. However, G' and G″ were improved by approximately 90% and 73.4%, respectively, when the GO content was increased to 7.5%. The moduli also displayed a relationship between the power function and concentration. Furthermore, the formation mechanism of GO/KGM was investigated by Raman, FT-IR, XPS and SEM. The results suggested that hydrogen bonding and physical crosslinking are generated from the abundant carboxy and hydroxyl groups of graphene oxide and the hydroxyl groups of konjac glucomannan.

Cotton carbon aerogel was prepared and used as a new water-insoluble adsorbent to remove strontium from aqueous solution. A comprehensive study on adsorption of strontium by cotton carbon aerogel was conducted regarding the effects of initial pH, temperature, initial strontium concentration, and contact time. The adsorbent was characterized by SEM. The results of regression analysis indicated that the adsorption process largely depends on the pH and temperature. The optimum pH range for adsorption process is 5–7. The maximum removal efficiency of strontium from aqueous solution was 60.16%. Moreover, cotton carbon aerogel adsorbent has good reusability before the fifth reuse.

A novel layered Zr-Al-La tri-metal composite (AZL) was fabricated via co-precipitation method for fluoride removal. The as-prepared adsorbent was characterized by various technologies, and its adsorption behaviors to fluoride were thoroughly carried out to investigate the fluoride removal performance. The results showed that the layered structure existed and the AZL exhibited the maximum adsorption capacity of 90.48 mg g-1 at 308 K and pH 3.0 from the Langmuir isotherm model. The adsorption kinetics was well fitted by the pseudo-second-order equation, and the adsorption isotherms were well described by the Langmuir equation. Adsorption thermodynamics result was indicative of endothermic reaction in the process of adsorption of AZL to fluoride. The as-prepared AZL composite has excellent fluoride removal performance for the practical ground water and satisfies the permissible limit of fluoride in drinking water recommended by Chinese Standard. In addition, based on the characterization, the adsorption mechanism of fluoride on AZL was proposed, including electrostatic interaction between the protonated surface of AZL and fluoride, as well as ion-exchange by hydroxyl group and fluoride.

This paper exhibits a rapid one-step hydrothermal method to prepare three different morphologies (spininess, columnar, lamelliform) of MnO2 covered on the surface of carbon spheres (CS@MnO2) by the control of KMnO4 concentration and hydrothermal temperature. All these CS@MnO2 composites were applied in supercapacitor electrode material, and the superior electrochemical performance of CS@MnO2 indicates that the combination of CS and MnO2 has a synergy effect on the enhancement of electrochemical performance. Among these samples, it is worth noting that the columnar morphology of CS@MnO2 exhibited the best performance achieving the max capacitance 178 F g−1 as the supercapacitor electrode material.

In this work, the efficient extraction of uranium in solution using Al2O3–SiO2-T was reported. Kinetics and isotherm models indicated that the removal process of uranium on Al2O3–SiO2-T accorded with pseudo-second-order kinetic model and Langmuir isotherm model, which showed that the adsorption process was a uniform mono-layer chemical behavior. The maximum adsorption capacity of Al2O3–SiO2-T reached 738.7 mg g−1, which was higher than AlNaO6Si2 (349.8 mg g−1) and Al2O3–SiO2-NT (453.1 mg g−1), indicating that the addition of template could effectively improve the adsorption performance of Al2O3–SiO2 to uranium. Even after five cycles of adsorption–desorption, the removal percentage of uranium on Al2O3–SiO2-T remained 96%. Besides, the extraction efficiency of uranium on Al2O3–SiO2-T was 72.5% in simulated seawater, which suggested that the Al2O3–SiO2-T was expected to be used for uranium extraction from seawater. Further, the interaction mechanism between Al2O3–SiO2-T and uranium species was studied. The results showed that the electrostatic interaction and complexation played key roles in the adsorption process of Al2O3–SiO2-T to uranium.

In this study, porous Al2O3-SiO2 composite materials were successfully constructed and applied to remove Th(IV) in aqueous solution. There was a large amount of OH− on the surface of Al2O3-SiO2 composite materials in aqueous solution, which would effectively capture positively charged Th(IV) to form a complex. The maximum adsorption capacity reached 361.60 mg g−1 and the adsorption percentage was as high as 99.9% in low initial concentration of Th(IV) solution. In addition, it was worth noting that the adsorption efficiency could maintain more than 90% even after 5 cycles. In view of these results, porous Al2O3-SiO2 composite materials should be considered to be an efficient and reusable adsorbent for Th(IV).

Fluorinated graphene (FG) as energetic material has a wide range of application due to its unique light-to-heat conversion, thermal and oxidation properties. The structure of FG, especial the fluorinated degree of FG is a key parameter to achieve those applications. In this study, the effect of the fluorinated degree of FG on the laser ignition of a typical energetic material of 2,4,6,8,10,12-(hexanitrohexaaza) cyclododecane (CL-20) was studied by the density functional theory (DFT) calculations and experimental characterizations. The interaction mechanism between the FG and CL-20 was studied by the simulation through adsorption energy and the electron density difference variations. Simultaneously, graphene materials with different fluorinated degrees were prepared by the hydrothermal method experimentally, the photothermal conversion behavior and laser ignition characteristics of graphene with different degrees of fluoride were characterized. Simulation and experimental results show that CL-20 and graphene with a low degree of fluorination have stronger adsorption energy and lower laser induced ignition delay time than those of the other conditions. This research provides an atomic-scale explanation for the laser induced ignition mechanism of fluorinated graphene in energetic materials.

Hydroxyapatite (HAP) was a highly efficient uranium adsorbent and its adsorption performances were depended on morphology and structure. In order to obtain HAP with better morphology and structure, HAP aerogels were prepared via freeze-drying-calcination method with konjac gum, xanthan gum and chitosan as template in this work. In contrast, HAP aerogel prepared with konjac gum as template (K-HAP) possessed better pore structure and particle distribution, providing more adsorptive sites for the removal of uranium from wastewater. The adsorption efficiency and capacity of uranium on K-HAP were 99.2% and 2070.3 mg g-1, respectively, which were much higher than many absorbents reported (pH = 4, m/V = 0.1 g L-1 and T = 298 K). The immobilization of uranium on HAP aerogel could be explained by the formation of Ca(UO2)2(PO4)2⋅3H2O. Due to the remarkable adsorption performance, K-HAP was supposed to be applied in the practical treatment of uranium-containing wastewater in the future.

Electrolysis of seawater makes full use of this natural resource and continuously turns it into a clean fuel, hydrogen. Electrocatalysts for seawater electrolysis must maintain a steady-state operation without suffering from chloride corrosion. In this study, we report a three-dimensional structure metal phosphide electrocatalyst by depositing cobalt-doped Fe2P (Co-Fe2P) on Ni foam. Density functional theory calculations showed that Co-Fe2P was beneficial for the hydrogen evolution reaction (HER) because of its suitable H* adsorption. Thus, the as-prepared Co-Fe2P acted as an efficient bifunctional electrocatalyst, exhibiting enhanced electrocatalytic properties for both the oxygen evolution reaction (OER) and HER. Moreover, the simulated alkaline seawater was used to determine the optimum potential (1.69 V at 100 mA cm−2) required for seawater splitting using the as-synthesized electrocatalyst. This study proposes a novel material for electrocatalytic application.

Two-dimensional graphene has become one of the most intensively explored carbon allotropes in materials science owing to its attractive features, such as its outstanding physicochemical properties. To advance its practical application, the fabrication of self-assembled 2D graphene sheets into 3D nitrogen-doped graphene aerogels (NGA) with novel functions is becoming essential. Herein, the first attempts to modify graphene with Plectranthus amboinicus (PA), to introduce double nitrogen doping, and to prepare NGA by a natural drying (ND) method are reported. Natural drying was achieved by increasing the pore structure of NDPA-NGA using PA to simultaneously cross-link the graphene sheets and increase the stiffness of the sample. Meanwhile, we used ammonia and urea as double nitrogen sources to achieve an N-doping amount as high as 12.06 atom %. In addition, NDPA-NGA exhibited superelastic properties (with 95% maximal strain and almost no loss after 60 replicates), a high oil absorption capacity, and an excel...

Herein, we harmonized the energy band of defective molybdenum disulfide (MoSx) and reduced graphene oxide (RGO) through manipulating the concentration of S vacancies for efficient U(VI) reduction. The analysis of band structure revealed that the EF and conduction band of MoSx downward shifted with the increase of S vacancies, which lowered the schottky barrier but simultaneous decreased the reducibility of photogenerated electrons. Accordingly, the removal rate of U(VI) under the irradiation of simulated sunlight exhibited a volcanic relationship with the concentration of S vacancies in MoSx/RGO. Specifically, the maximum removal rate reached 91.6% with nearly 83.4% of tetrahydrated uranium (U(IV)) species over MoSx/RGO heterojunction. In addition, the extraction efficiency of MoSx/RGO heterojunction kept steady in 5-cycle test and exhibited less than 4.5% decrease in the presence of non-redox-active competing metal cations.

The novel MnxTi1-xOy composite materials with different mole ratios (Mn to Ti = 3:7, 5:5 and 7:3) were prepared to remove uranium species from wastewater. These composite materials were characterized by various techniques, such as thermogravimetric analysis (TG), X-ray diffraction (XRD), Fourier transformed infrared (FT-IR) and scanning electron microscopy (SEM). It was found that the chitosan in MnxTi1-x-Chi were completely removed after calcination at 650 °C and MnxTi1-xOy composites possessed uniform distribution of the porous structure as well as plentiful hydroxyl-containing groups. Moreover, the as-prepared MnxTi1-xOy composite materials were applied to remove uranium from solution to evaluate the adsorption performance. It was found that the Mn0.5Ti0.5Oy possessed relatively excellent uptake performance for uranium comparing with the Mn0.3Ti0.7Oy and Mn0.7Ti0.3Oy and its maximum uptake capacity and efficiency reach 695.2 mg/g and 98.6% (pH = 4, m/V = 0.1 g/L, T = 298 K), respectively, which were much superior than most of reported materials based on titanium oxide or manganese oxide. Besides, the uranium uptake on Mn0.5Ti0.5Oy was independent on ionic strength and it had considerable reusability, which might be the necessary condition for Mn0.5Ti0.5Oy to be applied in uranium uptake from uranium-containing wastewater. As a candidate adsorbent, Mn0.5Ti0.5Oy possessed a high potentiality to remove uranium from wastewater.

Photoreduction of soluble U(VI) into insoluble U(IV) servers as a novel and efficient approach for U(VI) enrichment, where semiconductors are generally applied as the photocatalysts. Unfortunately, only a part of sunlight is utilized during the photoreduction process, significantly limiting the treatment performance for U(VI). Herein, we successfully constructed highly active and stable photocatalysts for the photo-assisted treatment of U(VI) by depositing Cu80Co5Ni5Cd5In5 nanocrystals on porous ZnO (CCNCI/ZnO) to efficiently expand the response region of sunlight. Impressively, the U(VI) enrichment capacity of CCNCI/ZnO was up to 2405.3 mg/g within 60 min. Moreover, CCNCI/ZnO exhibited excellent stability during photocatalysis due to the enhanced entropy of Cu80Co5Ni5Cd5In5 nanocrystals. Further mechanistic studies indicated that Cu80Co5Ni5Cd5In5 nanocrystals in CCNCI/ZnO generated hot electrons under visible light, followed by the transformation of hot electrons to porous ZnO via the Schottky barrier. Hot carriers efficiently reduced U(VI) over CCNCI/ZnO, contributing to the remarkable performance during U(VI) enrichment.

Three kinds of nano-manganese oxide materials were prepared at different temperature (500, 600 and 700 °C) using chitosan as the template agent. The results showed that there was no sintering and agglomeration in the calcination of nano-manganese oxide at 600 °C, while the manganese oxide material calcined at 700 °C showed pore collapse and agglomeration and the template agent was incompletely removed in the manganese oxide material calcined at 500 °C. The adsorption properties of uranium (VI) on the three manganese oxide materials were investigated. The experimental results showed that the adsorption behavior conformed to the pseudo-second-order kinetics and Langmuir isotherm models, revealing that the adsorption behavior of uranium (VI) on manganese oxide materials was a uniform and monolayer chemical adsorption process. The adsorption capacity of MnO-600 was 635.4 mg/g and the adsorption efficiency was above 90% after five cycles. In conclusion, the novel manganese oxide materials would have a prospect for application in wastewater treatment.

With the continuous increase in the demand for energy storage equipment, it is imperative to develop new electrode materials with high specific capacitance. In this study, yak dung derived carbon materials (N-YD) were prepared by a simple, economical, and effective method, and it was applied as a supercapacitor electrode material. The N-YD-800 material exhibited high nitrogen content, as well as a large number of multipore structures, which were beneficial to improve the capacitance performance. N-YD-800 exhibited an excellent specific capacitance (346.3[Formula: see text]F[Formula: see text]g[Formula: see text] at 1[Formula: see text]A[Formula: see text]g[Formula: see text], good rate performance (56.6% from 0.5[Formula: see text]A[Formula: see text]g[Formula: see text] to 10[Formula: see text]A[Formula: see text]g[Formula: see text], and excellent cycling stability (93.3% after 5000 cycles). This study provided a new method for the treatment of livestock and poultry manure resources, affording a cost-effective, easy-to-use carbon source to solve the problem of nonrenewable energy.

As a safe, reliable, and strongly electromagnetic resistant initiation method, laser initiation shows great promise in military blasting applications. Many obstacles exist when delivering a high-energy laser through optical fibers, directly influencing the energetic explosives under low-initiation conditions. Herein, we developed silver nanoplates as a laser energy absorber to reduce the laser initiation threshold and delay time. During the growth process of the silver seed nanoplates, mechanical disturbance was applied to provoke the nanoplates to develop more internal hotspots. Meanwhile, in ultraviolet visible near-infrared (UV–VIS-NIR) testing, the absorption peak was regulated to 808 nm by tailoring the size of the nanoplates. Results showed that the maximum temperature of the cracking nanoplates could reach 100 °C within 10 s, under the irradiation of an 808 nm diode laser at a power density of 1 W·cm−2. Through their use as a laser energy absorber, the silver nanoplates can effectively reduce the initiation threshold of cyclotrimethy lenetrinitramine (RDX) by 58.33% and reduce the delay time of B/KNO3 by 51.00%. This result provides potential applications for initiation energetic explosives at low laser energy.