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A SnOS/GNS nanocomposite consisting of a single phase nanocrystal (3–5 nm) improves the kinetics of the electrochemical reactions of lithium-ion batteries.

The electrocatalytic reduction of nitrobenzene to aniline normally faces high overpotential and poor selectivity because of its six-electron redox nature. Herein, a Ag nanoparticles/laser-induced-graphene (LIG) heterointerface was fabricated on polyimide films and employed as an electrode material for an efficient nitrobenzene reduction reaction (NBRR) via a one-step laser direct writing technology. The first-principles calculations reveal that Ag/LIG shows the lowest activation barriers for the NBRR, which could be attributed to the optimum adsorption of the H atom realized by the appropriate interaction between Ag/LIG heterointerfaces and nitrobenzene. As a result, the overpotential of the NBRR is reduced by 217 mV after silver loading, and Ag/LIG shows a high aniline selectivity of 93%. Furthermore, an electrochemical reduction of nitrobenzene in tandem with an electrochemical oxidative polymerization of aniline was designed to serve as an alternative method to remove nitrobenzene from the aqueous solution. This strategy highlights the significance of heterointerfaces for efficient electrocatalysts, which may stimulate the development of novel electrocatalysts to boost the electrocatalytic activity.

Olefin epoxidation is an essential transformation and arouses great interest among the scientific community for the key role of epoxide in the chemical industry.

Iron difluoride (FeF2) is considered a high-capacity cathode material for lithium-ion batteries. However, its specific capacity and stability are limited by the poor electrochemical kinetics of conversion reactions. Herein, the conversion reaction is confined in a localized nanosized space by encapsulating FeF2 nanoparticles in polymer gelatin. The FeF2 nanocrystal-coated polyvinylidene fluoride-based layer (defined as FeF2@100%G-40%P) was synthesized by glucose-assisted in-situ gelatinization to construct an artificial cathode solid electrolyte interphase via a solvothermal process. Thanks to the improved kinetics of the localized conversion reaction, the obtained FeF2@100%G-40%P electrodes show good cyclic stability (313 mA h g−1 after 150 cycles at 100 mA g−1, corresponding to a retention of 80%) and a high rate performance (186.6 mA h g−1 at 500 mA g−1).

Adsorptive separation of propylene/propane (C 3 H 6 /C 3 H 8 ) mixture is highly desired for its potential energy saving on replacing currently deployed and energy-intensive cryogenic distillation technique. Realizing efficient C 3 H 6 /C 3 H 8 separation in the emerging hydrogen-bonded organic frameworks (HOFs) is very challenging and has been rarely reported due to the lack of functional sites for preferential gas binding. By virtue of crystal engineering, we herein report a rare example of functionalized HOF (termed as HOF-16 ) with free -COOH sites for the efficient separation of C 3 H 6 /C 3 H 8 mixtures. Under ambient conditions, HOF-16 shows a significant C 3 H 6 /C 3 H 8 uptake difference (by 76%) and selectivity (5.4) in contrast to those of other carboxylic acid-based HOFs. Modeling studies indicate that free -COOH groups together with the suitable pore confinement facilitate the recognition and high-density packing of gas molecules. The separation performance of HOF-16 has also been validated by breakthrough experiments. HOF-16 is stable in harsh condition including strong acidity and water.

Broad absorption spectra with efficient generation and separation of available charge carriers are indispensable requirements for promising semiconductor-based photocatalysts to achieve the ultimate goal of solar-to-fuel conversion. Here, Cu3−xSnS4 (x = 0−0.8) with copper vacancies have been prepared and fabricated via solvothermal process. The obtained copper vacancy materials have extended light absorption from ultraviolet to near-infrared-II region for its significant plasmonic effects. Time-resolved photoluminescence shows that the vacancies can simultaneously optimize charge carrier dynamics to boost the generation of long-lived active electrons for photocatalytic reduction. Density functional theory calculations and electrochemical characterizations further revealed that copper vacancies in Cu3−xSnS4 tend to enhance hydrogen’s adsorption energy with an obvious decrease in its H2 evolution reaction (HER) overpotential. Furthermore, without any loadings, the H2 production rate was measured to be 9.5 mmol·h−1·g−1. The apparent quantum yield was measured to be 27% for wavelength λ > 380 nm. The solar energy conversion efficiency was measured to be 6.5% under visible-near infrared (vis-NIR) (λ > 420 nm).

Photocatalysis is considered a remarkable green method in the catalytic degradation of wastewater; however, the collection and loading of the powdered catalyst is still a problem. The traditional coating methods are usually unstable for the (photo-)degradation of organic binders. Herein, monolithic structures based on 2D–2D interactions instead of traditional 0D–0D and 1D–1D interactions were designed and constructed, realizing an interlocked structure with 3D active carbon fiber networks via the self-assembly of Bi2O2CO3 nanosheets (B-ACF) during the hydrothermal process. The loaded catalyst was further modified via an I-doping improvement strategy (4B-ACF-I), which exhibited 8 times the catalytic activity as compared to the intrinsic Bi2O2CO3. Thanks to the 3D monolithic and interlocked structure of loaded catalysts, B-ACF-I photocatalysts could be reused without any loss of catalytic activity during the cycling stability test. The expanded experiment and the removal of Cr(VI) under visible light prove that our improvement strategy can be considered even in actual wastewater treatment.

The NaTi2(PO4)3 (NTP) anode materials exhibit high Na+ diffusion dynamics; carbon-based materials can effectively improve its limited electronic conductivity. However, the low Na+ diffusion of NTP/C composite materials from inhomogeneous carbon mixing or uncontrollable carbon coating cannot keep up with fast electron transfer, leading to undesirable electrochemical performances. Herein, a uniform and controllable carbon layer is designed on the self-supported-coated NTP nanorod arrays with binder-free (NTP@C NR) to improve Na+ and electron kinetics simultaneously. As a result, the NTP@C NR electrodes possess initial coulombic efficiency (ICE = 97%), good rate capabilities (89.1 mA h g-1 at 100 C), and stability with ≈78.4% of capacity retention rate at even 30 C over 1200 cycles. The sodium-ion capacitors with NTP@C NR as an anode and commercially activated carbon as a cathode exhibit ∼9180.0 W kg-1 of power density at 10 A g-1 and super high retention of ≈94.5% at 1 A g-1 over 7000 cycles. This work will help balance transport kinetics between the ion and electron for materials applied in storage devices.

As a large trading nation, China competes with importing countries’ domestic and third‐country markets but also creates growth opportunities for exporters. Most studies on China trade shocks or “China shocks” focuse on the impacts of import competition on developed economies. The present paper complements research on China shocks by exploring the other side of the trade exposure to China – China as the largest importer, rather than as an exporter. We analyze the effects of export expansion into China on the local labor markets of the exporting developing countries for the years 1992 to 2018. Using detailed export and employment data, we estimate employment pattern variations in manufacturing industries with exports from other developing countries as instruments for export exposure. We find that the increase in trade exposure to China in the world economy has caused extensive job gains in manufacturing industries in developing countries that were exporters. On average, our estimations show that this trade exposure created approximately 1.5 million additional jobs from 1992 to 2018, which made an important contribution to manufacturing industries in developing countries. Our empirical analysis also shows that trade had stabilizing effects on employment in the countries in our sample generally.

Electrocatalytic N2 reduction to ammonia is a fascinating alternative to Haber-Bosch process and also considered as an energy storage method. This work, Fe doped MoS2/carbon cloth (CC) has been studied on the electro-catalysis fix nitrogen indicating the doped Fe can indeed enhance the MoS2 material ability. Compared with MoS2/CC, Fe-Mo-S-3/CC not only increases 10 times in the rate of production ammonia, but also 5 times in Faraday efficiency.

PEDOT PSS has been studied as a silicon-based binder due to its inherent superior electricity and electrochemical stability. However, it cannot effectively alleviate the huge volume changes of silicon during lithiation/delithiation due to its linear structure, resulting in poor cycling stability. Ion-cross-linking is a usual method to cross-link linear polymers into 3D structures. In this paper, multivalent cations of the 5th period and Group 2 cross-linked PEDOT:PSS were applied as silicon anode binders and studied systematically. It was found that the variation trend of viscosity and conductivity of PEDOT:PSS after cross-linking was consistent with that of ionic potential and softness parameters of multivalent cations. The mesostructure of a binder after cross-linking is influenced by the solubility product constant of sulfites or hydroxides of cations and the growth characteristics of crystals. An Sn4+-cross-linked binder displayed increased viscosity and electrical conductivity and higher reduced modulus and hardness due to its positive softness parameter and higher ion potential. The Si electrode with the Sn4+-cross-linked binder showed improved cycling stability (1876.4 mAh g-1 compared with 1068.4 mAh g-1 of the electrode with the pure PEDOT:PSS binder after 100 cycles) and superior rate capability (∼800 mAh g-1 at an ultrahigh current density of 8.0 A g-1).

The separation of C2H2/CO2 is particularly challenging owing to their similarities in physical properties and molecular sizes. Reported here is a mixed metal-organic framework (M'MOF), [Fe(pyz)Ni(CN)4] (FeNi-M'MOF, pyz=pyrazine), with multiple functional sites and compact one-dimensional channels of about 4.0 angstrom for C2H2/CO2 separation. This MOF shows not only a remarkable volumetric C2H2 uptake of 133 cm3 cm-3, but also an excellent C2H2/CO2 selectivity of 24 under ambient conditions, resulting in the second highest C2H2-capture amount of 4.54 mol L-1, thus outperforming most previous benchmark materials. The separation performance of this material is driven by π-π stacking and multiple intermolecular interactions between C2H2 molecules and the binding sites of FeNi-M'MOF. This material can be facilely synthesized at room temperature and is water stable, highlighting FeNi-M'MOF as a promising material for C2H2/CO2 separation.

In this work, grain boundary (GB) potential barrier ( Δφ GB), dopant density (Pnet), and filled trap state density (PGB,trap) were manipulated at the nanoscale by exposing the fabricated perovskite films to various relative humidity (RH) environments. Spatial mapping of surface potential in the perovskite film revealed higher positive potential at GBs than inside the grains. The average Δφ GB, Pnet, and PGB,trap in the perovskite films decreased from 0% RH to 25% RH exposure, but increased when the RH increased to 35% RH and 45% RH. This clearly indicated that perovskite solar cells fabricated at 25% RH led to the lowest average GB potential, smallest dopant density, and least filled trap states density. This is consistent with the highest photovoltaic efficiency of 18.16% at 25% RH among the different relative humidities from 0% to 45% RH.

The gram-scale selective oxidation of biomass-based chemicals, in particular 5-hydroxymethylfurfural (HMF), into value-added 2,5-diformylfuran (DFF) has a high application potential but suffers from high cost, low selectivity, and harsh reaction conditions. Besides, the electrooxidation strategy requires the usage of expensive electrodes and struggles with low selectivity and efficiency, which restricts its further scaled-up application. In this regard, a continuous-flow system was developed through redox mediator I

Solar steam generation has great potential in alleviating freshwater crises, particularly in regions with accessible seawater and abundant insolation. Inexpensive, efficient, and eco-friendly photothermal materials are desired to fabricate sunlight-driven evaporation devices. Here, we have designed an economical strategy to fabricate a high-performance wood-based solar steam generation device. In current study, 3D-hierarchical Cu

Lithium-sulfur (Li-S) batteries, as a prospective energy storage system, are still plagued by many problems that prevent them from their application, especially the low content of sulfur in the cathode. Herein, a cathode material with S up to 93 wt % is designed via a hollow donor-π-acceptor heterosystem, which combines catalytic sites, adsorption sites, and good conductivity together. Following this guidance, a hollow porous carbon sphere is prepared with CoO particles and single V atoms decorated on it (Co/V-HPCS), providing ultrahigh volumetric space for sulfur. Even the electrode made of sulfur-loaded Co/V-HPCS (Co/V-HPCS@S) has a high content of 90 wt % (sulfur content in the electrode is ∼83.5 wt %), and the cathode exhibits an excellent discharge capacity of 575.2 mAh g-1 under 0.2C after 100 cycles. With careful analysis by means of a high-resolution transmission electron microscope (HRTEM), the catalytic amounts of CoO particles and single V atoms loaded on the carbon shell are confirmed, which endows the material with outstanding catalytic ability to transfer sulfur and excellent adsorption of polysulfides. This concept of the cathode material increases the possibility of advanced long-life Li-S batteries with high tap density and high energy density.

SnO2 is widely used for ethanol-sensing applications due to its excellent physicochemical properties, low toxicity and high sensitivity. However it is a challenge to construct 3D-hierarchical structures with sub 5 nm primary grain particle, which is the optimized size for ethanol sensor. Herein, genetic tri-level hierarchical SnO2 microstructures are synthesised by the genetic conversion of 3D hierarchical SnS2 flowers assembled by ultrathin nanosheets. The SnS2 nanosheets are morphology genetic converted to porous nanosheets with sub 5 nm SnO2 nanoparticles during the calcination process. When used for the detection of ethanol, the sensor exhibits a high sensitivity of 0.5 ppm (Ra/Rg = 6.8) and excellent gas-sensing response (Ra/Rg = 183 to 100 ppm) with short response/recovery time (12 s/11 s). The excellent gas sensing performance is much better than that of the previous reported SnO2-based sensors. The highly sensitivity is attributed to the large surface area derived from the recrystallization and volume changes, which offers more active sites during the morphology genetic conversion from SnS2 to SnO2. Furthermore, the flower-like 3D structure enhances the stability of the materials and is beneficial for the mass diffusion dynamics of ethanol.

Aqueous polysulfide/iodide redox flow batteries (RFBs) are an attractive candidate for scalable energy storage with highly soluble active materials, which show great potential to reduce RFB cost. However, their energy efficiency is usually limited by poor kinetics reversibility and electrochemical activity of the redox reaction of polysulfide couples on the graphite felt electrode, which hinder its further practical applications. Here, Cu2XGeS4 (X = Fe, Co, Ni, Cd, Mn) nanocrystals are successfully synthesized through the hot injection method, and then uniformly coated onto the surface of graphite felt as electrodes. These electrodes can successfully suppress the water splitting side reactions, especially the hydrogen evolution reaction. The ones with Cu2CoGeS4 nanocrystals can significantly boost electrocatalytic activities of S2−/Sx2− redox reactions for the proper adsorbability of polysulfide, which inturn improve the charge transfer process and selectively facilitate the electro-conversion reactions of polysulfides. Furthermore, the polysulfide/iodide flow battery with GF–Cu2CoGeS4 generates a high energy efficiency of 77.2% at 20 mA cm−2, a power density of 40.7 mW cm−2 and a stable energy efficiency retention of 92% after approximately 250 continuous cycles.

The modulation of electron density is an effective option for efficient alternative electrocatalysts. Here, p-n junctions are constructed in 3D free-standing FeNi-LDH/CoP/carbon cloth (CC) electrode (LDH=layered double hydroxide). The positively charged FeNi-LDH in the space-charge region can significantly boost oxygen evolution reaction. Therefore, the j at 1.485 V (vs. RHE) of FeNi-LDH/CoP/CC achieves ca. 10-fold and ca. 100-fold increases compared to those of FeNi-LDH/CC and CoP/CC, respectively. Density functional theory calculation reveals OH- has a stronger trend to adsorb on the surface of FeNi-LDH side in the p-n junction compared to individual FeNi-LDH further verifying the synergistic effect in the p-n junction. Additionally, it represents excellent activity toward water splitting. The utilization of heterojunctions would open up an entirely new possibility to purposefully regulate the electronic structure of active sites and promote their catalytic activities.

Metal–organic-frameworks are good photocatalyst candidates due to their high surface area and semiconductor behavior, however the direct application of single-component MOFs is limited by their poor electronic conductivity and high combination rate of the photogenerated charge carriers. Meanwhile, silver phosphate (Ag3PO4) is a new emerging promising visible light photocatalyst but suffers from low stability. A promising strategy to overcome the shortcomings is to construct the nanocomposite photocatalysts. Herein, we report a rare example of a novel visible light active Ag3PO4/Fe-MIL-88-NH2 nanocomposite material. The resulting nanocomposite material shows improved RhB photodegradation catalytic efficiency than individual MOF and Ag3PO4 single components. Moreover, the Ag3PO4/Fe-MIL-88-NH2 nanocomposite material demonstrates good stability. The mechanism of the photocatalytic RhB degradation was investigated by introducing different scavengers to compete for the possible reactive species involved in the degradation process. The present study highlighted the very promise of constructing the Ag3PO4/MOF nanocomposite materials for efficient organic pollutants degradation in waste water.

If counter electrodes (CEs) could also contribute to light harvesting in dye-sensitized solar cells (DSSCs), then the power conversion efficiency (PCE) of DSSCs would be further boosted without changing the device structure. Nearly monodispersed Ag2 Se nanocrystals with a bandgap of 1.62 eV (∼765 nm) were synthesized via a one-pot process, and Ag2 Se CEs were fabricated by using a spin-coating and annealing process. Incident photon-to-current conversion efficiency and photocurrent spectra indicated that Ag2 Se CEs can generate the electricity by harvesting more visible light, which could not be absorbed by dye-sensitized photoanodes. Thus, compared to Pt CE (7.57 %), the DSSC based on Ag2 Se CE exerted a higher PCE of 8.06 %. The development of photovoltaic CEs may offer an alternative way to promote the performance and competitiveness of DSSCs.

It's still challenge and urgent to develop highly efficient and robust catalyst for the large-scale preparation of low-cost dye-sensitize solar cells (DSSCs). We presented here the successful synthesis of ternary CuFeSe2 nanocubes through a facile hot-injection method for utilization as counter electrode (CE) catalyst in DSSCs for the first time. Due to their reasonable charge-transfer ability, excellent electrocatalytic activity and the fast reduction reaction kinetics for the I−/I3− redox couples, the resultant DSSC with CuFeSe2 achieved an impressive power conversion efficiency of 8.05% under AM1.5G illumination (100 mW cm−2), comparable with that of standard Pt electrode based device (7.73%). Additionally, the CuFeSe2 CE exhibited better corrosion resistance in the iodine electrolyte than Pt CE. The easy fabrication process, cost-effectiveness, good electrocatalytic performance as well as excellent chemical stability help the CuFeSe2 nanocubes stand out as an alternative CE electrocatalyst in DSSC.

SnO

Silicon is a low price and high capacity anode material for lithium-ion batteries. The yolk-shell structure can effectively accommodate Si expansion to improve stability. However, the limited rate performance of Si anodes can’t meet people’s growing demand for high power density. Herein, the phosphorus-doped yolk-shell Si@C materials (P-doped Si@C) were prepared through carbon coating on P-doped Si/SiOx matrix to obtain high power and stable devices. Therefore, the as-prepared P-doped Si@C electrodes delivered a rapid increase in Coulombic efficiency from 74.4% to 99.6% after only 6 cycles, high capacity retention of ∼ 95% over 800 cycles at 4 A·g−1, and great rate capability (510 mAh·g−1 at 35 A·g−1). As a result, P-doped Si@C anodes paired with commercial activated carbon and LiFePO4 cathode to assemble lithium-ion capacitor (high power density of ∼ 61,080 W·kg−1 at 20 A·g−1) and lithium-ion full cell (good rate performance with 68.3 mAh·g−1 at 5 C), respectively. This work can provide an effective way to further improve power density and stability for energy storage devices.

Highlights γ-Glycidoxypropyl trimethoxysilane (GOPS) was incorporated in Si/PEDOT:PSS electrodes to construct a flexible and conductive artificial solid-electrolyte interphase (SEI). XPS Ar+ etching depth analysis proved that the addition of GOPS is conducive to forming a more stable SEI. A full battery assembled with NCM 523 cathode delivers a high energy density of 520 Wh kg-1, offering good stability. Electronic supplementary material The online version of this article (10.1007/s40820-020-00564-5) contains supplementary material, which is available to authorized users., Huge volume changes of Si during lithiation/delithiation lead to regeneration of solid-electrolyte interphase (SEI) and consume electrolyte. In this article, γ-glycidoxypropyl trimethoxysilane (GOPS) was incorporated in Si/PEDOT:PSS electrodes to construct a flexible and conductive artificial SEI, effectively suppressing the consumption of electrolyte. The optimized electrode can maintain 1000 mAh g−1 for nearly 800 cycles under limited electrolyte compared with 40 cycles of the electrodes without GOPS. Also, the optimized electrode exhibits excellent rate capability. The use of GOPS greatly improves the interface compatibility between Si and PEDOT:PSS. XPS Ar+ etching depth analysis proved that the addition of GOPS is conducive to forming a more stable SEI. A full battery assembled with NCM 523 cathode delivers a high energy density of 520 Wh kg−1, offering good stability. Electronic supplementary material The online version of this article (10.1007/s40820-020-00564-5) contains supplementary material, which is available to authorized users.

This study replicates Ahn, Khandelwal, and Wei’s (2011) model of intermediary trade. The study produces two main results. First, the authors are able to reproduce empirical evidence for AKW’s three main predictions for Chinese exports. This is impressive because much of the data for their replication are independently sourced. However, when the authors subject their model to additional tests, they find that the evidence is not robust. Using more recently available data to test AKW′s first prediction, the authors estimate coefficients that are wrong-signed and significant. When they re-analyze the evidence supporting the second and third predictions, they find that the full sample results mask significant heterogeneity across Chinese regions. In many cases, key coefficients are insignificant. In a few cases, they are wrong-signed and significant. Finally, using multiple versions of a key variable measuring the number of required import documents by country, the authors discover that the results are not robust across versions.

The NaTi

ObjectData on the characteristics and related factors of fungal empyema thoracis (FET) are limited. Our aim is to investigate the clinical characteristics and related factors of FET.MethodsWe conducted a retrospective study of patients with positive culture from pleural effusion who were admitted to the First Affiliated Hospital of Soochow University between January 2007 and January 2018. The clinical and laboratory characteristics of all study participants were collected. Logistic regression models were used to assess the related factors of FET.ResultsThere were 30 patients diagnosed with FET. The median age of patients with FET was 62.7 years old and 24 (80.0%) were male. The most frequent pathogens of FET were Candida albicans (55.9%). Diabetes mellitus (23.3% vs. 7.9%, P = 0.019) and upper gastrointestinal tract perforation or rupture (20.0% vs. 2.1%, P