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Three-dimensionally macroporous (3DOM) MnSmOx composite oxides were prepared via a hard-template method and utilized as catalytic materials for propane combustion. The modification effect of samarium dopant on both their physicochemical and catalytic properties were systematically investigated by means of characterization techniques and experimental approaches. Characterization results revealed that the increasing addition of samarium into MnOx favored the formation of 3DOM structure, and the doping of samarium induced the crystalline phase transformation of Mn2O3 into Mn3O4, concurrently leading to the remarkable improvement of redox ability and surface oxygen mobility as well as higher abundance of surface labile oxygen species. All above-mentioned properties were demonstrated to be the major determinants for boosting the propane combustion performances of Sm-doped catalysts. Among all, the 3DOM Mn0.85Sm0.15Ox (denoted as M0.85S0.15) exhibited the optimum catalytic activity and good regeneration capacity under humid conditions. Additionally, the comparative in situ DRIFTs analysis over M0.85S0.15 and the bulk counterpart (denoted as B-M0.85S0.15) emphasized the superiority of 3DOM architecture on promoting the surface adsorption and oxidation of propane molecules.

The viability of applying high capacity sulfur cathodes is hindered by the rapid capacity fading, structure degradation, and severe safety problem. Unfortunately, these problems still existed when the lithium-sulfur batteries (LSBs) faced with commercial applications. Consequently, it is urgent to find perfect strategies to modify the properties of LSBs for achieving wide applications. Herein, we present a detailed host material study by immersing sulfur into cobaltous sulfide host materials. Via the material characterization and electrochemical study, some meaningful results were obtained for the sulfur-based cathode during the electrochemical cycles. The electrochemical properties indicated that the as-prepared cobaltous sulfide/S composite cathode exhibited high initial specific capacity and low self-discharge in the LSBs.

α-MoO3 is a promising electrode material for electrocapacitive energy storage. However, it has poor stability in aqueous electrolytes due to dissolution in water. Here, we demonstrate that an α-MoO3 electrode prepared using the electrochemical deposition method is stable over a wide potential window of 2.2 V in a neutral aqueous electrolyte. The improved stability of the α-MoO3 electrode in water is attributable to enhanced electron conductivity, which minimizes the polarization-induced structural collapse, and the dense microstructure of the α-MoO3 film electrode. The widened potential window is related to the electrocatalytic inactivity of the α-MoO3 toward water electrolysis and the high overpotentials of the neutral electrolyte toward H2 and O2 evolution reactions. A symmetric supercapacitor cell fabricated with the electrochemically deposited α-MoO3 electrode delivers a specific energy as high as ∼22 Wh/kg at a specific power of ∼301 W/kg. This work demonstrates that the electrochemical deposition method is a viable approach to fabricating α-MoO3 electrodes for aqueous electrochemical energy storage.

Silica scalant and organic foulant are rapidly deposited onto the surface of a thin-film composite (TFC) reverse osmosis (RO) membrane during the desalination process. The scaling and fouling prope...

Lithium-sulfur batteries are considered to be an ideal high-performance rechargeable lithium battery. However, some problems have seriously hindered the practical application of lithium-sulfur batteries. A simple one-step hydrothermal method has been applied to design nitrogen-doped graphene aerogel (N-GA) with three different nitrogen sources. Subsequently, sulfur was encapsulated in N-GA by chemical deposition method to synthesize sulfur encapsulated in N-GA (N-GA/S) composites. Among them, the N-GA1/S composite with sulfur content reaching 75.5 wt% has a discharge specific capacity of 723.9 mAh g−1 after 100 cycles at 0.7 C, and the capacity retention rate is up to 87.4% while the coulombic efficiency still remains 98%. The outstanding electrochemical performance is owing to the good coating of sulfur by nitrogen-doped graphene aerogel, the improvement of the conductivity of the graphene skeleton by nitrogen doping, and the strong adsorption capacity of the doped nitrogen atom to lithium polysulfide. The graphene skeleton also helps to reduce the volume effect while charging and discharging. Furthermore, the proportion of pyridinic-N in N-GA1/S composites is higher than that in the two other composites, and it has a better adsorption capacity for lithium polysulfide.

This paper presents a review of research progress for biomass-derived hard carbon materials for sodium-ion storage. It provides an in-depth analysis of hard carbon anode materials obtained from biomass with the aim of identifying an optimal structure performance relationship. Different sodium-ion storage mechanisms in hard carbon and models proposed in the literature are discussed and compared. Hard carbon property – performance correlations are analysed based on recent published data. This paper also provides insight into the common methods for preparing hard carbon from biomass, as well as effect of preparation conditions on the physical properties of hard carbon materials. Observed structural changes are directly correlated with preparation parameters and biomass precursor used. In most cases, biomass derived hard carbon materials thermally treated between 1200 °C and 1400 °C have been identified as providing ideal structural properties for improving sodium-ion storage performance in battery cells. However, certain drawbacks including poor cycling stability and low initial coulombic efficiency still hinder the wider applications of hard carbon for sodium-ion batteries. To that end, methods for addressing the negative performance characteristics are provided, including the requirement for novel characterization techniques and advanced material engineering.

Metal–organic frameworks (MOFs) are a novel category of crystalline porous materials, which have become preferred heterogeneous catalysts for many reactions. MOFs are widely used in catalysis because of a combination of many advantages, such as large pore dimensions and surface area, abundant active sites, and possibility to be designed and modified after synthesis. As an important branch of the MOF family, lanthanide metal–organic frameworks (Ln-MOFs)—comprising a variety of multitopic organic ligands and Ln3+ ions/clusters—are a very fascinating MOF materials with complex and diverse topologies. As the functional metal center of MOFs, lanthanide metal ions have a higher coordination number and abundant coordination geometries compared with transition metal ions, which establishes the potential application of Ln-MOFs in the field of catalysis. In addition, Ln-MOFs have the same characteristics as MOFs, including structural diversity and tailorability, high surface area, and high thermal and chemical stability; therefore, Ln-MOFs and their derivatives are suitable for heterogeneous catalysis under various conditions. In this review, an overview of the recent developments achieved in Ln-MOF catalysis, including heterogeneous organic catalysis and photocatalysis over Ln-MOFs and their derivative materials, is provided.

The electrochemical reduction of carbon dioxide (CO2RR) requires access to ample gaseous CO2 and liquid water to fuel reactions at high current densities for industrial-scale applications. Substantial improvement of the CO2RR rate has largely arisen from positioning the catalyst close to gas–liquid interfaces, such as in gas-diffusion electrodes. These requirements add complexity to an electrode design that no longer consists of only a catalyst but also a microporous and nanoporous network of gas–liquid–solid interfaces of the electrode. In this three-dimensional structure, electrode wettability plays a pivotal role in the CO2RR because the affinity of the electrode surface by water impacts the observed electrode reactivity, product selectivity, and long-term stability. All these performance metrics are critical in an industrial electrochemical process. This review provides an in-depth analysis of electrode wettability's role in achieving an efficient, selective, and stable CO2RR performance. We first discuss the underlying mechanisms of electrode wetting phenomena and the foreseen ideal wetting conditions for the CO2RR. Then we summarize recent advances in improving cathode performance by altering the wettability of the catalyst layer of gas-diffusion electrodes. We conclude the review by discussing the current challenges and opportunities to develop efficient and selective cathodes for CO2RR at industrially relevant rates. The insights generated from this review could also benefit the advancement of other critical electrochemical processes that involve multiple complex flows in porous electrodes, such as electrochemical reduction of carbon monoxide, oxygen, and nitrogen.

Owing to the high energy density and rich resource, Li–S batteries are now considered as a promising direction in energy storage. Nevertheless, the electrochemical properties of sulfur host materials have been limited by the large volume changes during cycles, the dissolution of polysulfides in an electrolyte, and the insulating properties of lithium polysulfides. Based on the above conclusions, a novel cathode material of graphene nanosheet@spherical ordered mesoporous carbon/sulfur nanocomposite (GNs@s-OMC/S) where s-OMC/S was wrapped by GNs has been synthesized in this article and delivers superior cycle stability. According to the tests, GNs@s-OMC/S provides a capacity of 1159 mAh g−1 at a 0.4 C discharge rate. In addition, even at a high rate of 4 C, the discharge capacity of GNs@s-OMC/S can also remain 767 mAh g−1, representing a fantastic rate performance and high specific capacity. It can be ensured that the narrow channels provided by s-OMC and the graphene entrapment with high conductivity enhance the electrochemical performance of the cathode.

Micro-structured optical film is one of the micro-optical elements and has a great market demand. This article studies the microstructured optical film formed by UV imprinting: The influence of embossing pressure on microstructure replication accuracy was explored. The larger the pressure, the better the material filling. When the pressure is 5N, the microstructure replication is complete; The relationship between the radiation intensity and warpage deformation was explored, and the decrease in the intensity of the UV light source can effectively reduce the warpage deformation; The influence of the material formula on the optical properties of the product was explored. When the oligomer content was 55%, the film had a high light transmittance. At the same time, the prepared film was subjected to an apparent inspection with good microstructure replication accuracy.Microstructured optical elements are widely used in optical fields such as semiconductors, lasers, beam shaping [1-2] and solar energy [3-5] due to their unique advantages such as small size and high performance. As a key component in many industries, it has a high market demand rate. However, the microstructure forming process is complicated, the manufacturing cost is high, and the accuracy is difficult to guarantee, which has restricted its development. With the advancement of science and technology and the increase in market demand, more and more researchers and enterprises have put their eyes on the research of preparing micro-structured optical elements.At present, the commonly used microstructures are mainly icrolens array [6-8], and the processing methods include micro-imprinting [9-10], etching [11], electron beam direct writing, and micro-injection [12], etc. This article studies the UV-curing embossing process in micro-embossing. This processing method has the advantages of fast molding, high efficiency, and environmental protection. And this process is conducive to mass production and has a broad market application prospect.In this paper, the forming process and material formulation of microstructured optical film prepared by light-cured micro-imprinting were investigated, and the microstructure morphology of the preparation was analyzed apparently.

M–Nb–O compounds are regarded as advanced anode materials of lithium-ion batteries owing to their large capacities, high safety and fast Li+ transport. However, challenges remain in the exploitation of new M–Nb–O compounds with low strains to enable superior cyclability. Here, we exploit V3Nb17O50 as a low-strain M–Nb–O anode compound, and V3Nb17O50 micron-sized particles (V3Nb17O50-MP) and submicron-sized rods (V3Nb17O50-SR) are demonstrated. V3Nb17O50 owns an open and robust shear ReO3 crystal structure, which is constructed by 3 ​× ​3 ​× ​∞ (V,Nb)O6 octahedron-blocks linked by VO4 tetrahedra. The resulting A–B–A layered structure with a large interlayer spacing enables the superior Li+ diffusivity and significant intercalation-pseudocapacitive behavior in V3Nb17O50. The maximum unit-cell volume expansion of V3Nb17O50 discharged to 0.8 ​V is only 3.46% (the smallest value among the known M–Nb–O anode compounds with shear ReO3 structures), leading to the excellent cyclability of V3Nb17O50-MP/V3Nb17O50-SR with 90.0/91.8% capacity retention over 2000 cycles at 10C. V3Nb17O50-MP/V3Nb17O50-SR further exhibits a safe operating potential of 1.736/1.724 ​V, large reversible capacity of 207/254 ​mA ​h g−1 at 0.1C, and high rate performance with 68/123 ​mA ​h g−1 at 10C. A LiMn2O4//V3Nb17O50-SR full cell also exhibits comprehensively good electrochemical properties, including excellent cyclability with 85.7% capacity retention over 500 cycles at 5C. Therefore, V3Nb17O50 can be a very promising anode compound for stable, safe, large-capacity and fast-charging Li+ storage.

Crystal morphology has a significant effect on the properties and applications of energetic materials (EMs). Here, we have combined the single-crystal X-ray diffraction (SCXRD) and rotation imaging...

Potassium‐ion storage is being explored by researchers for its advantages in forming graphite‐based intercalation compounds, with cost‐effective production compared to lithium‐ion systems. However, its poor performance in graphite‐based platforms, owing to the volume expansion required for intercalation, has demanded alternative materials for reversible potassiation. Herein, we demonstrate a simple one‐step pyrolysis approach to develop an amorphous hard carbon material from commercial cellulose for high‐performance potassium‐ion batteries (KIB). The larger interlayer spacing (~0.4 nm) alongside the electronegative oxygen functional groups promotes potassium‐ion storage. High capacity, good rate and long cycling performance with lower‐volume expansion could be credited to the amorphous carbon that possesses turbostratic nanodomains. Further, oxygen functional groups on the carbon material are identified in our experimental studies, and density functional theory simulations indicate that these are likely to enhance the potassium ion capacity of the materials.

A series of chitosan (CS)-coated metal–organic-framework (MOF) nanoparticles, which combined excellent chemical stability, thermal stability, and recyclability, were synthesized by an in situ growt...

Three-dimensionally macroporous (3DM) MnZrOx catalysts were fabricated to reveal the structure and Zr-doping effects on both physicochemical properties and propane combustion behaviors. The increasing addition of zirconium is favorable for the formation of 3DM structure and amorphous Mn-Zr solid solution, leading to tunable physicochemical properties. The significant activity improvement after zirconium addition was originally attributable to the superior redox ability, higher oxygen mobility and more abundant oxygen vacancy. The excellent catalytic activity, cycling stability and water resistant ability over 3DM Mn0.6Zr0.4Ox make it a promising material for hydrocarbons elimination. The comparative TPSR, in situ DRIFTs and kinetics study over 3DM and bulk catalysts emphasize the advantageous function of 3DM architecture on promoting propane adsorption, oxidation and lattice oxygen mobility.

Hollow perovskite oxide La0·5Sr0·5MnO3 nanospheres are synthesized by using carbon spheres as template in the presence of citric acid. Among the samples investigated in this work, the one obtained at a sintering temperature of 700 °C exhibits the highest catalytic activity in the oxygen reduction reaction (ORR) in an alkaline electrolyte. The electrochemical measurement data shows that the sample has a positive onset potential (0.860 V) and a high limiting current density (6.48 mA cm−2). Furthermore, the catalyst shows a high selectivity towards methanol and a better stability than a commercial Pt/C catalyst. The hollow La0·5Sr0·5MnO3 nanoshperes described in this manuscript hold a great promise for applications in metal-air batteries and alkaline fuel cells.

Sodium-ion batteries are a promising alternative to lithium-ion batteries. In particular, organic sodium-ion batteries employing environmentally friendly organic materials as electrodes are gaining increasing research interest for developing secondary batteries as a result of the ease of processing, low cost, and flexibility of the organic electrode materials. Triquinoxalinylene (TQA) is a very promising organic electrode material for sodium-ion batteries. However, the poor cycling stability of TQA is impeding its adoption as an electrode material. In this work, we investigated the sodium-ion storage mechanism in TQA and the decay in capacity using both experimental and computational means. A strategy for improving the cycling stability is proposed, and it is demonstrated that the retention of capacity can be significantly improved from 31 to 85%.

Highlights Cobalt sulphide nanoparticles are encapsulated in nitrogen-rich carbon cages via a simple and scalable method.Insight into sodium storage mechanism is systematically studied via in situ TEM and XRD techniques.The sodium-ion capacitor device achieved high energy densities of 101.4 and 45.8 Wh kg−1 at power densities of 200 and 10,000 W kg−1, respectively, holding promise for practical applications. Electronic supplementary material The online version of this article (10.1007/s40820-020-0391-9) contains supplementary material, which is available to authorized users., Conversion-type anode materials with a high charge storage capability generally suffer from large volume expansion, poor electron conductivity, and sluggish metal ion transport kinetics. The electrode material described in this paper, namely cobalt sulphide nanoparticles encapsulated in carbon cages (Co9S8@NC), can circumvent these problems. This electrode material exhibited a reversible sodium-ion storage capacity of 705 mAh g−1 at 100 mA g−1 with an extraordinary rate capability and good cycling stability. Mechanistic study using the in situ transmission electron microscope technique revealed that the volumetric expansion of the Co9S8 nanoparticles is buffered by the carbon cages, enabling a stable electrode–electrolyte interface. In addition, the carbon shell with high-content doped nitrogen significantly enhances the electron conductivity of the Co9S8@NC electrode material and provides doping-induced active sites to accommodate sodium ions. By integrating the Co9S8@NC as negative electrode with a cellulose-derived porous hard carbon/graphene oxide composite as positive electrode and 1 M NaPF6 in diglyme as the electrolyte, the sodium-ion capacitor full cell can achieve energy densities of 101.4 and 45.8 Wh kg−1 at power densities of 200 and 10,000 W kg−1, respectively. Electronic supplementary material The online version of this article (10.1007/s40820-020-0391-9) contains supplementary material, which is available to authorized users.

Sodium-sulfur batteries (NaSBs) have emerged as a promising energy storage technology for large-scale stationary applications such as smart electrical grids due to their exceptionally high energy density and cost-effectiveness. However, one of the challenging problems impeding their practical applications is the sulfur shuttle effect by which the active redox intermediates are gradually dissolved in electrolytes. In this work, we have employed first-principles density functional theory (DFT) calculations to unravel the suppression of the shuttle effect in NaSBs with a two-dimensional (2D) As2S3 monolayer as the anchoring material. We show that semiconducting As2S3 is a suitable anchoring layer to inhibit the dissolution of the polysulfide intermediates in common electrolytes because of its stronger chemical binding with sodium polysulfides than with the electrolytes. The immense adsorption is attributed to the electron donation from the unfilled S-3p states of the polysulfides to As2S3. These mechanisms increase the carrier population and consequently improve the electrical conductivity of As2S3. Hence, the use of As2S3 can both reduce the shuttle effect and enhance the cathode electron conductivity to enable improved cycling stability and coulombic efficiency of the battery.

The oxygen reduction reaction (ORR) is one of the most important electrochemical reactions in energy conversion and storage technologies, such as fuel cells and metal–air batteries. However, the sluggish kinetics of the ORR is a key factor limiting the performance of these energy storage and conversion devices. Perovskite oxides are a promising family of electrocatalysts for the ORR because of their unique physical and chemical properties, such as variable crystal structure and non-stoichiometric chemistry. Studies have shown that the catalytic properties of perovskite oxides in the ORR are largely related to oxygen vacancies, which alter their electronic and crystal structures and surface chemistry. This review summarizes recent research advances on understanding the role of oxygen vacancies of the ABO3 perovskite oxides in catalyzing the ORR. With a brief introduction of perovskite oxides, approaches to creating oxygen vacancies in the ABO3 perovskite oxides and the role of oxygen vacancies in improving their catalytic performance for the ORR are discussed. Research perspectives in this important area are highlighted.

The removal of radioiodine from the exhaust gas streams produced in spent fuel reprocessing plants is of paramount importance for the nuclear fuel cycle's security. Here, millimeter-sized poly(vinylidene fluoride) (PVDF) composites containing zirconium-based metal–organic frameworks, MOF-808, were synthesized by a facile phase inversion method to adsorb the volatile iodine. MOF-808@PVDF composites have inherited the crystallinity and pore accessibility of MOF-808, as well as its outstanding iodine capture performance. The MOF-808@PVDF composite beads containing 70 wt% MOFs, exhibited ultrahigh iodine adsorption capacity, 1.42 g g−1 at 80 °C, much higher than other millimeter-sized adsorbents reported in the literature. Raman mapping suggests that the negative iodine ions were formed at the early stage of iodine adsorption, while the close-packed iodine molecules were subsequently trapped in the frames. Using dynamic adsorption, the influences of iodine concentration, operating temperature and humidity were analyzed to evaluate its application potential in industrial conditions. The iodine adsorption capacity could reach 1.36 g g−1 at 80 °C, 100 °C and 120 °C in flow gas. And the elevated temperature (120 °C) is beneficial to accelerating the mass transfer of iodine vapor, as well as slightly inhibiting the competitive adsorption of water molecules under humidity. Besides, only one-third of the loaded iodine was released in nitrogen purging after saturated adsorption. The remaining majority was trapped firmly by the beads due to their strong interactions with the frameworks. This work highlights the millimeter-sized MOF-808@polymer composite beads with ultrahigh iodine adsorption capacity, providing experimental references for their application in radioiodine removal from hot and moist streams.

In this study, we prepared a Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) cathode layer for proton-conducting solid oxide fuel cells using microwave sintering. Unlike traditional sintering, which is carried out at 1000 °C for a few hours, the microwave sintering method allows the BSCF cathode layer to adhere well with the electrolyte layer after sintering at 900 °C for 10 min. This strategy helps the cathode layer maintain a microstructure favourable for cathode reactions and mitigate the potential diffusion of elements between it and the BaZr0.1Ce0.7Y0.2O3-δ electrolyte, leading to improved cell resistance. The cell with the BSCF cathode layer sintered by the microwave method has a power output of 0.96 W cm-2 at 700 °C, while the power output for the cell with a conventionally sintered cathode is 0.33 W cm-2.

CeO2 nanocubes with (100) surface orientation are successfully synthesized and found to facilitate the sinterability of CeO2 material. The CeO2 nanocubes show a much-improved sinterability relative to CeO2 nanoparticles prepared by the conventional citric-nitrate method. The nanocubes can be successfully sintered at a relatively low temperature of 1200 °C without using any sintering aids. In contrast, a pellet using conventional CeO2 nano-powder obtained from the conventional citric-nitrate method can be densified only after sintering at 1400 °C, which is 200 °C higher than that for the CeO2 nanocube sintering, although the starting particle size of both CeO2 samples is similar. Density functional theory indicates that the surface energy of the (100) plane is significantly higher than that of the (111) plane, which is the more typical surface presentation of conventional CeO2 particles. This high surface energy allows fast growth of the CeO2 nanocubes during sintering, contributing to their improved sinterability.

The graphite felt (GF) was modified through the concentrated sulfuric acid, potassium permanganate and ammonia activation with the aim of improving the specific surface area, hydrophilicity and the electrocatalytic activity for the electrogeneration of hydrogen peroxide and its application in the electro-Fenton (EF). The modified graphite felt (M-GF) was characterized by contact angle, scanning electron microscope, X-ray photoelectron spectroscopy, Raman spectrum, cyclic voltammetry and electrochemical impedance spectroscopy. The surface physic-chemical characteristics and morphology of the M-GF were considerably changed after the modification. The current efficiency for H 2 O 2 generation was explored at an optimized current density of 10 mA cm −2 and the value of H 2 O 2 generation for the M-GF was 478.6 mg L −1 , while the GF was 276.5 mg L −1 after 360 min of electrolysis. Finally, the M-GF was used for the mineralization of aniline (100 mg L −1 ), reaching a mineralization percentage of 97% with EF process. The M-GF demonstrated good stability as the aniline mineralization percentage was above 90% after 10 cycles’ degradation, indicating that the M-GF is a promising cathode material for improving the degradation and mineralization of others organic pollutants by the EF process.

This paper presents a novel method based on AC impedance for monitoring the curing process of epoxy resin. Effects of DMP-30 and temperature on the reaction rate and curing degree were investigated here. Experimental results showed that DMP-30 has significant influence on reaction rate of the curing system, and the resin system, containing 1.5 wt% DMP-30 can be cured completely in the shortest time at 80 °C. Impedance analysis showed that the curing degree increased obviously with increasing temperature, while the curing time got shortened sharply. DSC technique was also employed here to verify the effectivity of impedance analysis of curing degree, and a good agreement between AC impedance and DSC was observed, especially at higher temperature, demonstrating the great potential application of AC impedance in field of cure monitoring.

There is a growing demand for high-rate rechargeable batteries for powering electric vehicles and portable electronics. Here, we demonstrate a strategy for improving electrode performance by controlling the formation of solid electrolyte interphase (SEI). A composite electrode consisting of hard carbon (HC) and carbon nanotubes (CNTs) was used to study the formation of the SEI at different charging rates in an electrolyte consisting of 1 M NaClO4 in a mixed solvent with ethylene carbonate (EC) and propylene carbonate (PC), as well as fluoroethylene carbonate (FEC) additive. The half-cell method was used to form the SEI at different charging rates (e.g., 1, 10, and 100 A/g). Symmetric capacitor cells were employed to study ion transport properties through the SEI. It was found that the SEI is a primary factor responsible for limiting the capacity of the composite anode material in conventional ester-based electrolytes. The electrode with the SEI formed at 100 A/g exhibited the lowest impedance and delivered nearly twice the capacity of the electrode with the SEI formed at 1 A/g. This significant difference is due to a thin SEI formed at the fast charging rate, as has been observed with ether-based electrolytes. An identical decay rate (0.11 mA h/g per cycle) was observed on the electrodes with SEIs formed at different charging rates in an ester electrolyte. No chemical difference among the three SEI layers was found. However, morphological differences of the SEI layers were observed. This difference is believed to account for the different electrochemical behaviors of the electrodes. This work shows that high charging rates can result in the formation of an optimal SEI layer, contradicting the widely accepted practice of using low charging rates during the SEI formation in alkali-ion batteries.

High performance protective coatings applied under heavy duty condition will lengthen the structure’s service life, decrease maintenance times, economic and human life loss. Here, high protective performance coatings were prepared by dispersing polyaniline (PANI) nanowires into epoxy modified furfural-acetone (EMFA) resin matrix and then cured with phenalkamine. The protective performance of coatings was investigated by immersion experiments in 12% NaCl solution at 90 °C and Electrochemical Impedance Spectroscopy (EIS) measurements. The coating containing 1.0% PANI nanowires showed high impedance (>1010 ohm·cm2) after 80 days immersion, exhibiting great protective performance. X-ray photoelectron spectroscopy (XPS) surveys verified the formation of passive layer (Fe2O3/Fe3O4) on steel surface beneath the coating with 1.0% PANI. The bending test suggested that both the pure EMFA coating and the EMFA/PANI coating showed excellent flexibility of 2 mm. Here, measurement of water absorption, adhesion strength, pencil hardness and impact resistance were conducted to evaluate coatings performance.

This work investigates the performance of amine functionalised 2D/3D sorbents for CO2 capture. The 2D/3D structures were based on a combination of flake-like reduced graphene-silica oxide (G-Si) aerogel and rod-like mesoporous silica SBA-15. The G-Si aerogel formed mainly silica microporous structures which enveloped graphene sheets. The SBA-15 displayed the classical rod-like mesoporous features with high pore volume. The addition of G-Si aerogel to SBA-15 for the amine functionalised samples significantly reduced the combined total surface area and pore volume. Interestingly, the CO2 sorption capacity increased and peaked for samples containing G-Si aerogel/SBA-15 at 1:20 mass ratio (4.7 wt%), though declining thereafter. This counterintuitive effect of increasing CO2 sorption capacity but decreasing surface area and pore volume was attributed to the special morphological features of the 2D/3D sorbent assembly. At these optimal conditions, the flake-like G-Si aerogel was well intercalated with the rod-like SBA-15. As a result, the inter-particle space formed between the flake-like and rod-like assembly accommodated TEPA which facilitate the mass transfer and reaction between the amine groups and CO2. These special 2D/3D morphological features delivered high CO2 sorption capacity of 6.02 mmol g−1. The 2D/3D sorbents were also very stable under sorption and desorption cycles whilst heat of sorption were up to 22% lower than the analogue 3D SBA-15/TEPA sorbent.

In this work, we have firstly achieved the construction of bismuth oxyiodide (Bi5O7I)/reduced graphene oxide (rGO)/ZnO Z-scheme photoelectrochemical (PEC) system without backward reactions through loading large-area ZnO quantum dots (QDs)/rGO films on Bi5O7I nanosheets. Single-crystal porous Bi5O7I nanosheets with numerous oxygen vacancies (OVs) were firstly fabricated through the calcination of BiOI in reductive glycols. The single-crystal facilitates charge transport, nanoporous structure promotes light absorption and OVs improves charge separation efficiency. As a result, single-crystal porous Bi5O7I nanosheets with OVs exhibited higher PEC performance than other morphologies reported before. Moreover, The PEC activity of Bi5O7I can be further enhanced through loading large-area ZnO QDs/rGO films to construct a pure Z-scheme charge transfer system, which not only achieves efficient separation of electron-hole pairs but also retains its excellent redox ability. To the best of our knowledge, the photocurrent density of Bi5O7I/rGO/ZnO heterostructures is the highest among Bi5O7I-based samples. For comparison, an opposite Z-scheme model has also been built up by replacing Bi5O7I with WO3, in which the photocurrent density decreased conversely. Therefore, it can be known that a pure Z-scheme system without backward reactions can be successfully prepared through loading ZnO QDs/rGO films on photoelectrodes.

Polyamide (PA) thin film composite membranes consisting of a PA film (skin layer) formed via interfacial polymerization (IP) on a porous support are state of the art reverse osmosis (RO) membranes. The skin layer is thought to provide most resistance for transport and be responsible for separation. An ideal skin layer should be very thin with sufficient selectivity. However, it is challenging to obtain such a kind of skin layer. Herein, a novel concept of confining skin layer growth to reduce the resistance of skin layer significantly without sacrificing the selectivity of skin layer was proposed. The skin layer growth can be confined by a barrier, which can hinder the diffusion of aqueous phase monomers toward the organic phase during IP. Zeolitic imidazolate framework-8 (ZIF-8) particles were used as barriers in this work. By controlling the confinement, the skin layer thickness was reduced, meanwhile the sufficient selectivity of skin layer was maintained. Then, the flux was improved dramatically from 49.8 ± 1.1 L m−2 h−1 to 76.2 ± 3.4 L m−2 h−1 (by 53.0%), meanwhile a high rejection (99.06 ± 0.20%) was retained. Besides, the confinement led to a surface with lower roughness. The comparison of utilizing the barriers (ZIF-8 particles) and shortening the reaction time was also done. The results showed that (1) utilizing the barriers and shortening the reaction time share similarities and (2) utilizing the barriers is superior to shortening reaction time. The performance of membrane fabricated via the concept of confining the skin layer growth exceeds that of many previously reported membranes. This work might inspire the development of high performance membranes fabricated by IP with great potential for applications in molecular separations.

Efficient capture of benzoylurea insecticide (BU) residue in food is a vital procedure for food safe monitoring. Herein, a core-shell structured magnetic fluorinated covalent organic framework with good magnetic responsiveness and abundant fluorine affinity sites was successfully synthesized, suitable for magnetic solid-phase extraction (MSPE) of BUs. Using a room-temperature synthesis strategy, the magnetic fluorinated covalent organic framework was fabricated by in situ polymerization of 1,3,5-tris(4-aminophenyl) triazine (TAPT) and 2,3,5,6-tetrafluoroterephthaldehyde (TFTA) on the surface of carboxylated Fe3O4 nanoparticles. The competitive adsorption experiment and molecular simulation verified that this magnetic fluorinated covalent organic framework possesses favorable adsorption affinity for BUs. This magnetic fluorinated covalent organic framework could be easily regenerated and reused at least eight times with no reduction of enrichment performance. Combining this magnetic fluorinated covalent organic framework-based MSPE with high-performance liquid chromatography-tandem mass spectrometry, a novel sensitive method for the analysis of BUs was developed. In yellow wine and fruit juice samples, good linear correlations were obtained for BUs in the range of 10-2000 and 20-4000 ng·L-1, respectively. The limit of quantitation of the BUs ranged from 1.4 to 13.3 ng·L-1 in the two beverage matrices. Desirable precision was achieved, with intraday and interday relative standard deviations lower than 11%.

There has been rapidly growing interest in developing fast-charging batteries for electric vehicles. The solid electrolyte interphase (SEI) layer formed at the graphite/electrolyte interface plays an important role in determining the lithiation rate of lithium-ion batteries (LIBs). In this work, we investigated lithium-ion transport behavior in thin-film graphite electrodes with different graphite particle sizes and morphologies for understanding the role of the SEI layer in fast charging LIBs. We varied the properties of the SEI by changing the current rate during the SEI formation. We observed that forming the SEI layer at a much higher current density than is traditionally used leads to a substantial reduction in electrode impedance and a corresponding increase in ion diffusivity. This enables thin-film graphite electrodes to be charged at current rates as high as 12 C (i.e., about 5 min charging time), demonstrating that graphite is not necessarily prevented from fast charging. By comparing the SEI layers formed at different current densities, we observed that lithium-ion diffusivity across the SEI layer formed on a 23 μm commercial graphite at a current density currently used in the industry (e.g., 0.1 C) is approximately 8.9 × 10-10 cm2/s.

The osmotic/activity coefficients are one of the most fundamental and important properties of electrolyte solutions. There is currently no reliable means of predicting them from first principles without relying on extensive fitting to experimental measure- ments. The alkali hydroxide aqueous electrolytes are a particularly important class of solutions due to the crucial role they play in a vast range of applications. Here, for the first time we predict the osmotic/activity coefficients of these solutions without any fitting using a previously developed continuum solvent model of ion–ion interactions with no modifications. The feasibility of making these predictions with first princi- ples molecular simulation is also assessed. This demonstrates the reliability of this continuum solvent model and provides a plausible pathway to the fast and accurate prediction of these important properties for a wide range of electrolyte solutions.

We report a class of pKa-directed, precise incorporation of phosphonate ligands into a zirconium-based metal–organic framework (Zr-MOF), MOF-808, via ligand exchange. By replacing of formate ligand...

In this work, the effects of support surface pore structures (including surface pore size, surface pore density and surface porosity) on the performance of thin film composite (TFC) gas separation membrane over a wide pressure range (from 0.3 to 2.0 MPa) were studied. To fulfill it, the polysulfone (PSf) supports with different surface pore structures were prepared. Two kinds of wide-accepted polymeric membrane materials, i.e., polyvinylamine (PVAm) and Pebax 1657 copolymer, were used as skin layer materials. We pointed out for the first time that the support surface average pore size and pore density could affect the chain mobility of polymer of skin layer at the support surface pore entrance, then, can affect the TFC membrane performance. Besides, we also discussed the effects of support on the TFC membrane performance when the feed pressure changes for the first time. This work can provide guidance for choosing a suitable support for TFC gas separation membrane.

This work investigates the one-pot facile synthesis of novel 2D/3D assemblies containing graphene silica (templated) aerogel sorbents for CO2 capture, a greenhouse gas of major global concern. In t...

Membrane separation process is one of the most promising methods for post-combustion CO2 capture from coal-fired power plant. In this paper, a multicomponent gas separation process using spiral-wound membrane modules is explored to optimize its membrane area and energy consumption. Firstly, the parametric analysis is conducted for the single-stage membrane process to study the impact of the feed gas CO2 concentration, feed pressure and selectivity on the permeate gas flow rate, permeate gas CO2 concentration and membrane area. Secondly, a feasible procedure that maintains product purity and recovery is applied to discuss the impact of the membrane selectivity, permeance and the feed pressure on the two-stage membrane process. Based on the analysis and conclusions in the single-stage membrane process, the trade-off between membrane area and energy consumption has been analyzed in detail. By varying the selectivity and the feed pressure, the impact of these two parameters on the membrane area and energy consumption is discussed, finding that the combination of low selectivity in the first stage and high selectivity in the second stage has much smaller membrane area and slightly higher energy consumption than that of high selectivity in both stages. Moderate feed pressure, varying from 0.55 MPa to 0.65 MPa, is found to provide relatively low CO2 capture energy consumption. Techno-economic analysis is conducted to further validate the above strategy. To minimize the CO2 capture cost, high CO2 permeance and moderate selectivity is desirable for the first stage, while high selectivity and moderate CO2 permeance should be maintained for the second stage. The membrane developed for the flue gas CO2 capture do not have to simultaneously enhance the CO2/N2 selectivity and CO2 permeance. Even considering the uncertainties related to economic parameters, the optimum feed pressure that provides the minimum CO2 capture cost only varies from 0.69 MPa to 0.83 MPa.

Hollow porous nanoparticles were proposed to transform the skin layer structure for enhancing the performance of reverse osmosis (RO) membrane in this work. Amino-modified hollow mesoporous silica nanospheres (AHMSS) with a size from 110 to 130 nm were successfully prepared via the hard template method. AHMSS were added in the organic phase and then incorporated into the RO membrane skin layer after the interfacial polymerization process. The hydrophilicity of RO membrane was improved by AHMSS. The performance evaluation results showed that AHMSS improved the RO membrane flux (improved by 41.5%) with rejection decreasing slightly. Amino-modified mesoporous silica nanospheres without hollow cores were also prepared and incorporated into the RO membrane skin layer to investigate the effects of the hollow cores of AHMSS on the membrane performance. The results showed that the hollow cores of AHMSS contributed to the improvement of membrane performance. This work demonstrates that AHMSS have huge potential in preparing RO membranes with both high flux and high rejection.

Three-dimensional porous SnO2/rGO hollow spheres with abundant internal void space were designed to resolve the volume expansion problem of SnO2-based anode materials for sodium-ion batteries. The unique hollow spheres with a porous wall of SnO2 decorated GO sheets were realized by a facile spray drying method. Nanosized SnO2 particles, which uniformly anchored on graphene sheets, in situ formed at the hydrolysis stage. Ethanol was used as porosity tuning agent to achieve template free pore-forming. The hollow spheres of porous SnO2/rGO composite show superior sodium storage performance with large specific capacity, remarkable cycling stability and excellent rate capability. The as-prepared SnO2/rGO composite delivered a high initial discharge capacity of 821.6 mA h g−1 at 200 mA g−1, and even after 1500 charge/discharge cycles a discharge capacity of 204 mA h g−1 still can be obtained. The SnO2/rGO composite achieved a capacity of 213.1 mA h g−1 at 500 mA g−1 after 500 cycles. And maintained an enhanced rate capability of 231 mA h g−1 at 2000 mA g−1. The excellent cyclability and high-rate capability of the composite can be ascribed to its unique hollow/porous architecture and the synergistic effect between SnO2 nanoparticles and the conductive matrix of rGOs.

In the present work, perovskite oxides XReO3 (X = Rb, Cs, Tl) have been reported using density functional theory (DFT) for structural, electronic, mechanical, elastic, and thermodynamic properties. Structural optimization has been carried out using local density approximation (LDA) and generalized gradient approximation (GGA) in the scheme of Perdew, Burke, and Ernzerhof. Electronic properties have been calculated using GGA, and all the three materials were found to have metallic nature. From the elastic constants, all the three compounds were found mechanically stable in cubic structure. Poisson’s ratio (ν), Cauchy’s pressure (C 12–C 44) and Pugh ratio (B/G) present the ductile nature of RbReO3 and TlReO3, whereas CsReO3 was found to establish a brittle nature. These compounds were found to have an elastically anisotropic nature. The calculated melting temperatures were found to be 2851 ± 300, 2814 ± 300, and 2924 ± 300 K, respectively, for XReO3 (X = Rb, Cs, Tl). Using quasi-harmonic Debye approximation, we have calculated the pressure- and temperature-dependent variation in cell volume, bulk modulus, Debye temperature, and specific heat capacity.

This paper describes the syntheses and electrochemical properties of a new niobate compound, aluminum niobate (AlNb11O29), for Li+ storage. AlNb11O29-microsized particles and nanowires were synthesized based on the solid-state reaction and solvothermal methods, respectively. In situ X-ray diffraction results confirmed the intercalating mechanism of Li+ in AlNb11O29 and revealed its high structural stability against cycling. The AlNb11O29 nanowires with a novel bamboo-like morphology afforded a large interfacial area and short charge transport pathways, thus leading to the observed excellent electrochemical properties, including high reversible Li+-storage capacity (266 mA h g-1), safe operating potential (around 1.68 V), and high initial Coulombic efficiency (93.3%) at 0.1 C. At a very high rate (10 C), the AlNb11O29 nanowires still exhibited a capacity as high as 192 mA h g-1, indicating their good rate capability. In addition, at 10 C, 96.3% capacity was retained over 500 cycles, indicating superior cycling stability. A full cell fabricated with AlNb11O29 nanowires as the anode and LiNi0.5Mn1.5O4 microparticles as the cathode delivered a high energy density of 390 W h kg-1 at 0.1 C. This work suggests that the AlNb11O29 nanowires hold a great promise for the development of high-performance lithium-ion batteries for large-scale energy-storage applications.

The microwave sintering method is found to have advantages over the conventional thermal treatment method for preparing BaZr0.1Ce0.7Y0.2O3-δ powder. Comparing with the conventional thermal treatment, the microwave sintering method allows the solid material to be self-heated, enabling the formation of pure phase BaZr0.1Ce0.7Y0.2O3-δ powder at a relatively low temperature (900 °C) with a short dwell time of 1 h, while the same pure phase can only be formed at 1000 °C in an electric furnace. Importantly, the grain size for the microwave prepared BaZr0.1Ce0.7Y0.2O3-δ powder is much smaller than that of the conventionally thermal treated BaZr0.1Ce0.7Y0.2O3-δ powder. The small powder grain size is found to be beneficial for the densification and grain growth of the resultant electrolyte membrane during the electrolyte sintering procedure. A fuel cell fabricated using this electrolyte membrane with a conductivity of 7 × 10−3 S cm−1 delivers a power output of 791 mW cm−2 at 700 °C.

Here, a facile and low cost strategy combining co-solvent-optimized interfacial polymerization (CSO-IP) and protective coating-controlled chlorination (PCC-chlorination) for reverse osmosis membranes with high flux-rejection combinations is reported. CSO-IP, which provides a high performance membrane for the following chlorination, is the same as the conventional IP except adding a co-solvent in the organic phase. PCC-chlorination, which improves further the flux meanwhile retaining the high rejection, is the same as the conventional chlorination except adopting a protective coating. The coating preparation is fairly short and needs no complex chemistry. Due to the accelerated diffusion of aqueous phase monomer by the co-solvent, the membrane obtained by CSO-IP possessed a skin layer with thin and dense active layers. Besides, CSO-IP made membrane surface rougher. These endowed the membrane with a high performance (brackish water desalination testing conditions). Because of the heterogeneity of coating structure, some regions of membrane were attacked by chlorine and the others were protected during PCC-chlorination. Then, PCC-chlorination improved the flux further to 82.5 L m−2 h−1 meanwhile maintaining the high rejection (99.02%). This exceeds the performance of many previously reported membranes.

In this work, amorphous nickel–cobalt–manganese hydroxide (NiCoMn–OH) was hydrothermally synthesized using a mixed solvent strategy and used as positive electrode materials for supercapacitor-battery hybrid energy storage system. The experimental results show that the mixed solvent is indispensable to form the amorphous phase of NiCoMn–OH, which exhibits significantly improved electrochemical activity and rate capability in comparison with the crystalline counterpart because of more grain boundaries and ion diffusion channels in the former phase. A strong synergy between the transition metal ions in the amorphous NiCoMn–OH is found to significantly contribute to the electrochemical activity, rate capability and cycling stability. In addition to battery behavior, the amorphous NiCoMn–OH exhibits pseudocapacitive behavior, which contributes approximately 40% to the total energy storage capacity. The pseudocapacitive property significantly enhances the rate performance. The robust synthesis method described in this paper was also used to fabricate the NiCoMn–OH porous network on Ni foam, which shows a specific capacity close to its theoretical value, indicating a complete utilization of the electroactive material. Furthermore, a supercapacitor-battery hybrid cell fabricated with the amorphous NiCoMn–OH as the positive electrode and reduced graphene oxide (RGO) as the negative electrode exhibits both high-energy and high-power performances with a specific energy of 42.8 Wh kg–1 at a specific power of 749 W kg–1 or a specific energy of 19.9 Wh kg–1 at a specific power of 20.9 kW kg–1.