Synergy of inside doped metals–Outside coated graphene to enhance hydrogen storage in magnesium-based alloys

Grain growth of magnesium(Mg)and its hydride is one of the main reasons for kinetic and capacity degradation during the hydrogen absorption and desorption cycles.To solve this problem,herein we propose a novel method involving synergistic effect of inside embedded metals and outside coated graphene to limit the growth of Mg and its hydride grains.The graphene coated Mg-Y-Al alloys were selected as a model system for demonstrating this positive effect where the Mg_(91)Y_(3)Al_(6)alloy was first prepared by rapidly solidified method and then high-pressure milled with 5 wt%graphene upon 5 MPa hydrogen gas for obtaining in-situ formed YAl_(2)and YH_(3)embedded in the MgH_(2)matrix with graphene shell(denoted as MgH_(2)-Y-Al@GR).In comparison to pure MgH_(2),the obtained MgH_(2)-Y-Al@GR composites deliver much better kinetics and more stable cyclic performance.For instance,the MgH_(2)-Y-Al@GR can release about 6.1 wt%H_(2)within 30 min at 300℃ but pure MgH_(2)only desorbs∼1.5 wt%H_(2).The activation energy for desorption of MgH_(2)-Y-Al@GR samples is calculated to be 75.3±9.1 kJ/mol that is much lower than approximately 160 kJ/mol for pure MgH_(2).Moreover,its capacity retention is promoted from∼57%of pure MgH_(2)to∼84%after 50th cycles without obvious particle agglomeration and grain growth.The synergistic effect of outside graphene coating with inside embedded metals which could provide a huge number of active sites for catalysis as well as inhibit the grain growth of Mg and its hydride is believed to be responsible for these.

Synergy effects on Sn-Cu alloy catalyst for efficient CO2 electroreduction to formate with high mass activity

To acquire the synergy effects between Sn and Cu for the jointly high Faradaic efficiency and current density,we develop a novel strategy to design the Sn-Cu alloy catalyst via a decorated co-electrodeposition method for CO2 electroreduction to formate.The Sn-Cu alloy shows high formate Faradaic efficiency of 82.3%±2.1% and total C1 products Faradaic efficiency of 90.0%±2.7% at^-1.14 V vs.reversible hydrogen electrode(RHE).The current density and mass activity of formate reach as high as(79.0±0.4)mA cm^-2 and(1490.6±7.5)m A mg^-1 at^-1.14 V vs.RHE.Theoretical calculations suggest that Sn-Cu alloy can obtain high Faradaic efficiency for CO2 electroreduction by suppressing the competitive hydrogen evolution reaction and that the formate formation follows the path of CO2→HCOO*→HCOOH.The stepped(211)surface of Sn-Cu alloy is beneficial towards selective formate production.

Assessing the synergy effect of additive and matrix on single-crystal growth: Morphological revolution resulted from gel-mediated enhancement on CIT-calcite interaction

It is well known that in biomineralization, the inorganic solids crystallized in the presence of organic phases, which are generally recognized as additives and matrix, leading to the crystal morphology modification. However, the synergy effects of both soluble additive and insoluble matrix on regulating the morphology of synthetic single-crystals are less studied. Here, we examine the morphological revolution of calcite single crystals induced by the additive, citrate（CIT）, or/and the matrix, agarose gel network. The agarose gel matrix is inert to the crystal morphology in the sense that the agarose gelgrown calcite crystals maintain in characteristic rhombohedra. In contrast, CIT additives are active in crystal morphology modification and crystals begin to exhibit curved rough surfaces when grown in solution with the concentration of CIT coated Au nanoparticles（[CIT-Au NPs]） of more than 2.25 mg/mL.Interestingly, once agarose gel and CIT-Au NPs are simultaneously introduced, the curved morphological feature emerges at a much lower [CIT-Au NPs] of around 0.2 mg/mL. Increasing the gel concentrations further reduce the [CIT-Au NPs] needed to trigger calcite morphological modification, suggesting that the gel networks reduce the CIT diffusion and thereby enhance the kinetic effects of CIT on crystallization. As such, this work may have implications for understanding the mechanism of hierarchical biominerals construction and provide rational strategy to control single-crystal morphologies.

Relativistic effect on synergy of electron cyclotron and lower hybrid waves on EAST

In recent experiments on EAST,the electron temperature at the center can be raised to 9.7 ke V by injecting electron cyclotron(EC)and lower hybrid(LH)waves simultaneously.With such strong core electron heating,the relativistic effect could play an important role in the interactions between the plasma and waves.In order to explore the relativistic effect on synergy between the EC and LH waves on EAST,ray-tracing/Fokker-Planck simulations are conducted to investigate electron heating for a typical discharge with a center electron temperature of 9.7 ke V.It is found that the relativistic effect can cause the EC wave to deposit its power deeper in the plasma core,where the synergy between the EC and LH waves occurs and enhances the absorption of the LH waves.As a result,a high center electron temperature can be achieved.

Efficient simultaneous removal of diesel particulate matter and hydrocarbons from diesel exhaust gas at low temperatures over Cu–CeO_(2)/Al_(2)O_(3) coupling with dielectric barrier discharge plasma

Diesel particulate matter(DPM)and hydrocarbons(HCs)emitted from diesel engines have a negative affect on air quality and human health.Catalysts for oxidative removal of DPM and HCs are currently used universally but their low removal efficiency at low temperatures is a problem.In this study,Cu-doped CeO_(2) loaded on Al_(2)O_(3) coupled with plasma was used to enhance low-temperature oxidation of DPM and HCs.Removals of DPM and HCs at 200℃ using the catalyst were as high as 90%with plasma but below 30%without plasma.Operando plasma diffuse reflectance infrared Fourier transform spectroscopy coupled with mass spectrometry was conducted to reveal the functional mechanism of the oxygen species in the DPM oxidation process.It was found that Cu-CeO_(2) can promote the formation of adsorbed oxygen(M^(+)-O_(2)^(-))and terminal oxygen(M=O),which can react with DPM to form carbonates that are easily converted to gaseous CO_(2).Our results provide a practical plasma catalysis technology to obtain simultaneous removals of DPM and HCs at low temperatures.M+O-2Diesel particulate matter(DPM)and hydrocarbons(HCs)emitted from diesel engines have a negative affect on air quality and human health.Catalysts for oxidative removal of DPM and HCs are currently used universally but their low removal efficiency at low temperatures is a problem.In this study,Cu-doped CeO_(2) loaded on Al_(2)O_(3) coupled with plasma was used to enhance low-temperature oxidation of DPM and HCs.Removals of DPM and HCs at 200°C using the catalyst were as high as 90%with plasma but below 30%without plasma.Operando plasma diffuse reflectance infrared Fourier transform spectroscopy coupled with mass spectrometry was conducted to reveal the functional mechanism of the oxygen species in the DPM oxidation process.It was found that Cu–CeO_(2) can promote the formation of adsorbed oxygen(–)and terminal oxygen(M=O),which can react with DPM to form carbonates that are easily converted to gaseous CO_(2).Our results provide a practical plasma catalysis technology to obtain simultaneous removals of DPM and HCs at low temperatures.

CoB and BN composites enabling integrated adsorption/catalysis to polysulfides for inhibiting shuttle-effect in Li-S batteries

Lithium-sulfur(Li-S)batteries are hampered by the infamous shuttle effect and slow redox kinetics,resulting in rapid capacity decay.Herein,a bifunctional catalysis CoB/BN@rGO with integrated structure and synergy effect between adsorption and catalysis is proposed to solve the above problems.The integrated CoB and BN are simultaneously and uniformly introduced on the rGO substrate through a one-step calcination strategy,applied to modify the cathode side of PP separator.The transition metal borides can catalyze the conversion of lithium polysulfides(Li_(2)Sn,n≥4),whereas the bond of B-S is too weak to absorb LPS.Thus BN introduced can effectively restrict the diffusion of polysulfides via strong chemisorption with LiSnLi+…N,while the rGO substrate ensures smooth electron transfer for redox reaction.Therefore,through the integrated adsorption/catalysis,the shuttle effect is suppressed,the kinetics of redox reaction is enhanced,and the capacity decay is reduced.Using CoB/BN@rGO modified PP separator,the Li-S batteries with high initial capacity(1450 mAh g^(-1)at 0.35 mA cm^(-2))and long-cycle stability(700 cycles at 1.74 mA cm^(-2)with a decay rate of 0.032%per cycle)are achieved.This work provides a novel insight for the preparation of bifunctional catalysis with integrated structure for long-life Li-S batteries.

One-pot synthesis of mesosilica/nano covalent organic polymer composites and their synergistic effect in photocatalysis

Organic-inorganic hybrid materials provide a desirable platform for the development of novel functional materials.Here,we report the one-pot synthesis of mesoporous hybrid nanospheres by the in-situ sol-gel condensation of tetraethoxysilane around surfactant micelle-confined nano covalent organic polymer(nanoCOP)colloids.The hybrid nanospheres containing nanoCOPs uniformly distributed in the mesosilica network,inherited the visible light responsive properties of the nanoCOPs.The turnover frequency of the hybrid nanospheres is almost 12 times that of its corresponding bulk COP counterpart for the photocatalytic reductive dehalogenation of a-bromoacetophenone,which is attributed to activation of the Hantzsch ester reductant by the hydroxyl group.The existence of a volcano relationship between the activity and nano COP/mesosilica ratio confirmed the synergistic effect between nano COP and mesosilica.Our preliminary results suggest that hybridization of semiconductors and reactant-activating materials is an efficient strategy for enhancing the activity of a catalyst for photocatalysis.

Dual metal atom catalysts:Advantages in electrocatalytic reactions

The dual-metal-atom catalysts(DACs)have aroused much attention as they possess the advantages of single-atom and metal alloy catalysts.And the DACs have exhibited enhanced performance in various electrocatalytic reactions,such as hydrogen/oxygen evolution and oxygen/carbon dioxide/nitrogen reduction.In this review,we mainly overview the latest understanding of the advantages of DACs for these reactions.This review will start with the familiar characterization methods for DACs,then the primary synthesis strategies for DACs will be discussed.Emphasis is given to the advantages of DACs in catalytic reactions,including the adsorption and activation,electronic structure regulation,breaking scaling relations,reducing energy barriers,cascading and coupling,synergy effect,and providing mechanism research platforms.Finally,personal perspectives and challenges for the further development of DACs are briefly discussed.

Fabrication of Pd-based metal-acid-alkali multifunctional catalysts for one-pot synthesis of MIBK

The one-pot synthesis of methyl isobutyl ketone（MIBK） from acetone using multifunctional catalysts is an important sustainable organic synthesis method with high atom and energy efficiency.Herein. we report a series of Pd supported on mixed metal oxide（MMO） catalysts with controllable acidic/basic/metallic sites on the surface. We study the relationship between the nature, synergy,and proximity of active sites and the catalytic performance of the multifunctional catalyst in the tandem reaction, in detail. In the existence of Lewis acid and base sites, the catalysts with medium-strength acidic/basic sites show preferred activity and/or MIBK selectivity. For multifunctional catalysts, the catalytic properties are more than just a collection of active sites, and the Pd/Mg_3Al-MMO catalyst possessing 0.1% Pd loading and ~0.4 acid/base molar ratio exhibits the optimal 42.1% acetone conversion and 37.2% MIBK yield, which is among the best reported so far for this tandem reaction under similar conditions. Moreover, the proximity test indicates that the intimate distance between acidic/basic/metallic sites can greatly shorten the diffusion time of the intermediate species from each active site, leading to an enhancement in the catalytic performance.

Development of gold catalysts supported by unreducible materials:Design and promotions

Gold catalysis had been considered a highly efficient candidate for heterogeneous catalysis.It is well established that reducible-material-supported Au NPs are more reactive than the unreducible materials,unless specific modifications are carried out.However,unreducible materials such as carbon materials,silica,and alumina have particular advantages,including the easily controlled surface property,adjustable microscopic structure,earth-abundant reserves,and facile industrial manufacture.New strategies,influences,and mechanisms of modification to enhance the catalytic performance and thermal stability of unreducible-material-supported gold catalysts are among the most attractive research topics in gold catalysis.However,to the best of our knowledge,reports and reviews focused on unreducible-material-supported gold catalysts are lacking.Herein,the above concept will be thoroughly discussed regarding several typical unreducible supports,including the commonly used silica,alumina,carbon materials,and hydroxyapatite.The currently prevailing modification strategies will be summarized in detail from the aspects of theoretical conceptualization and practical methodology,including the ingenious synthesis method for catalyst with a specific structure,the currently prosperous electrostatic adsorption,colloid immobilization,and the applicative thermal gaseous treatment.The influences of physical and chemical modifications on the surface chemistry,electronic structure,interaction/synergy between Au-support/promoter,catalyst morphology and water precipitation will be also summarized.It is assumed that the review will shed light on significant studies on unreducible support in gold catalysis with the purpose of catalytic promotion and the promotion of the potential industrial demands in advance.Furthermore,the review will provide new insights into unreducible supports that can be potentially applied in gold catalysis.

Electrical Resistance Behavior of Vinylester Composites Filled with Glass-carbon Hybrid Fibers

Vinylester （bismethacryloxy derivative with glass-carbon hybrid fibers （CF-GF） weight fraction of a bisphenol-A type EP resin, VE） composites of 50%, were prepared by the compress molding method. The distribution of carbon fiber in the hybrids was observed by stereomicroscope. The electrical resistance behavior of the composites filled with different carbon fiber （CF） weight contents （0.5% to 20%） was studied. The experimental results show that the electrical resistance behaviors of CF-GF/VE composites are different with those of CF/VE composites because carbon fibers＇ conducting networks are broken by the glass fibers in the CF-GF/VE composites. The carbon fibers distribute uniformly in the networks of glass fibers （GF） like single silk and form the semi-continuous conducting networks. Composite filled with GF-CF hybrid has a higher percolation threshold than that filled with pure CF. At that time, the resistivity of CF-GF/VE composites varies little with the temperature increasing. The temperature coefficient of resistivity in GF-CF/VE composite is less than 317 ppm and the variation of the resistivity after ten thermal cycles from 20℃ to 240 ℃is less than 1.96%.

Carambola-like metal-organic frameworks for high-performance electrocatalytic oxygen evolution reaction

Hydrogen production by electrocatalytic water splitting promises a green and sustainable technology to address serious energy crisis and environmental pollution [1]. As well known, the process of electrocatalytic water splitting is composed of two half reaction, i.e. oxygen evolution reaction (OER) at the anode and hydrogen evolution reaction (HER) at the cathode [2].

An examination of active sites on Au-Ag bimetallic catalysts based on CO oxidation over Au/Ag_2O and a comparison to Ag-contaminated Au powder

There are two theories regarding the origin of the remarkable synergistic effect observed in Au‐Ag bimetallic catalysts when applied to various oxidative reactions. One is based on the importance of the contact interfaces between AgOx regions and the surface of the bulk Au as active working sites, while the other holds that charge transfer from Ag to Au in a surface Au‐Ag alloy causes the catalytic activity. One key point in examining these theories and determining the origin of the synergy in‐volves determining whether or not Ag exists as an oxide or as a metallic alloy on the Au surface. To confirm that enhanced activity results from contact between Ag2O and Au nanoparticles （NPs）, a comparative study of catalytic CO oxidation over Au/Ag2O and Ag2O was performed in the present work, using a closed recirculation reaction system. A reaction mixture consisting of a stoichiometric composition of CO and O2 （CO/O2=2/1） was supplied to both catalysts and the resulting pressure decrease rates were tracked, from which the amounts of gas consumed as well as the quantity of CO2 produced were determined. The steady state reactions of both Au/Ag2O and Ag2O did not lead to any meaningful difference in the rate of pressure decrease during the oxidation. The pressure decrease over both catalysts was attributed to the reduction of surface lattice O on Ag2O by CO. The results obtained for Au/Ag2O are in good agreement with previous data resulting from the use of Ag‐contaminated Au powder （Ag/Au‐b） having an oxidized surfaces. This finding suggests that the perimeters between AgOx zones and the bulk Au surface may not function as active sites during CO oxidation. A review of previous results obtained with Ag/Au‐b specimens having so‐called steady state surfaces indicates that AgOx species in such materials are reduced to the 0 state to form a Ag‐Au alloy that provides the active sites.

海胆状CoTe-CoP异质结构催化剂在全pH范围内高效析氢

研发长效稳定、pH适应性强的析氢反应(HER)催化剂对实现大规模制氢具有重要意义.界面工程是研发高效HER催化剂的有效策略之一.本文成功构建了海胆状异质结构催化剂CoTe-CoP/NF.CoTe和CoP的协同作用不仅优化了电子结构、暴露了更多的活性位点,而且有效地提高了催化剂的亲水性和疏气性.密度泛函理论计算表明:CoTe与CoP之间的相互作用有效地降低了水的解离能垒,同时增强了对H~*的吸附.这些结果使得CoTe-CoP/NF在整个pH范围内具有优异的HER性能和催化稳定性.在酸性、碱性和中性介质中,CoTe-CoP/NF电极驱动10 mA cm^(-2)的电流密度仅需51、53和75 mV的过电位.总之,本工作为在全pH范围内构建高性能HER催化剂提供了一种界面工程新策略.

Does urban technological innovation and cooperation promote its green development?Evidence from cities in the Beijing-Tianjin-Hebei urban agglomeration,China

The internal technological innovation(IT)and external technological cooperation(ET)of a city are crucial drivers for its green development(GD).Although previous studies have extensively explored the effect of IT on GD,IT,ET and GD have not been integrated into the same framework to explore their relationship.Using panel data of 13 cities in the Beijing-Tianjin-Hebei urban agglomeration,this study revealed the spatio-temporal evolution of GD and analyzed the effects of IT and ET on GD from the perspective of baseline impact,spatial effect and synergy effect.Empirical results demonstrate that the level of urban GD has upgraded and the difference in GD between cities has been narrowed though it decreases from the middle to both ends.IT significantly promotes the growth of GD while ET has an inverted U-shaped effect on GD.Under the influence of spatial spillover,IT has a U-shaped effect on the GD of neighboring cities while the effect of ET on neighboring GD is not significant.Additionally,the interaction between IT and ET has not been effective,leading to an insignificant synergy effect on GD.These findings will provide reference for taking rational advantage of IT and ET to facilitate urban GD.

Measuring drug similarity using drug–drug interactions

Combination therapy is a promising approach to address the challenge of antimicrobial resistance,and computational models have been proposed for predicting drug–drug interactions.Most existing models rely on drug similarity measures based on characteristics such as chemical structure and the mechanism of action.In this study,we focus on the network structure itself and propose a drug similarity measure based on drug–drug interaction networks.We explore the potential applications of this measure by combining it with unsupervised learning and semi-supervised learning approaches.In unsupervised learning,drugs can be grouped based on their interactions,leading to almost monochromatic group–group interactions.In addition,drugs within the same group tend to have similar mechanisms of action(MoA).In semi-supervised learning,the similarity measure can be utilized to construct affinity matrices,enabling the prediction of unknown drug–drug interactions.Our method exceeds existing approaches in terms of performance.Overall,our experiments demonstrate the effectiveness and practicability of the proposed similarity measure.On the one hand,when combined with clustering algorithms,it can be used for functional annotation of compounds with unknown MoA.On the other hand,when combined with semi-supervised graph learning,it enables the prediction of unknown drug–drug interactions.

The Effect of Online Channel Addition on Store Performance:Empirical Evidence from Chinese Chain Retailers

With the rapid development of e-Commerce and takeaway platforms, retailers have gradually developed multi-channel operations. However, limited empirical studies explored the effects of an online channel offered by takeaway platforms on the store performance. Does an online channel addition have a synergy effect or a cannibalization effect on store performance? We empirically investigate these effects by analyzing a large dataset including diverse samples collected from multiple retailers across various regions. The dataset includes 2115 stores across 25 retailers for 10 months that includes two types of retail formats and covers 16 provinces and 21 cities of China. We study the impacts of the newly introduced online channel on the incumbent offline channel and the overall store performance.The empirical results reveal that the online channel addition mainly has a synergy effect. Specifically,for the overall store, it has a positive effect on the sales and product variety, whereas it has a negative effect on the basket size. Surprisingly, an online channel addition also has a positive effect on the offline sales. Our study adds novel values to multi-channel retailing literature by empirically researching the cannibalization and synergy effect of a new type of online channel, offered by takeaway platforms. It can provide insights for retail enterprises who are interested in introducing O2 O model.

The role of bacteria and its derived biomaterials in cancer radiotherapy

Bacteria-mediated anti-tumor therapy has received widespread attention due to its natural tumor-targeting ability and specific immune-activation characteristics.It has made significant progress in breaking the limitations of monotherapy and effectively eradicating tumors,especially when combined with traditional therapy,such as radiotherapy.According to their different biological characteristics,bacteria and their derivatives can not only improve the sensitivity of tumor radiotherapy but also protect normal tissues.Moreover,genetically engineered bacteria and bacteria-based biomaterials have further expanded the scope of their applications in radiotherapy.In this review,we have summarized relevant researches on the application of bacteria and its derivatives in radiotherapy in recent years,expounding that the bacteria,bacterial derivatives and bacteria-based biomaterials can not only directly enhance radiotherapy but also improve the anti-tumor effect by improving the tumor microenvironment(TME)and immune effects.Furthermore,some probiotics can also protect normal tissues and organs such as intestines from radiation via anti-inflammatory,anti-oxidation and apoptosis inhibition.In conclusion,the prospect of bacteria in radiotherapy will be very extensive,but its biological safety and mechanism need to be further evaluated and studied.

Rational design of Prussian blue analogue-derived manganese-iron oxides-based hybrids as high-performance Li-ion-battery anodes

The unique components and architecture of Prussian blue analogous(PBAs) offer great potential for the construction of various functional nanostructures. Herein, we reported the preparation of a series of Mn–Fe oxides-based hybrids using Mn–Fe PBA as a template and an organic carbon source by calcination.The study focuses on revealing the interaction between the microstructure and electrochemical performance of the products obtained at different calcination temperatures. Notably, the as-derived porous Fe–Fe0.33Mn0.67O/C nanocubes(i.e., M600) exhibited the best rate capability and cycle life compared with other samples(~890 m Ah/g at 0.1 A/g, 626.8 m Ah/g after 1000 cycles at 1.0 A/g with a 99% capacity retention). These can be attributed to the fact that the porous structure provides shorter Li+diffusion path and promotes the penetration of electrolyte. Besides, the N-doped C formed by the carbonization of organic ligands can buffer the volume change and prevent the aggregation of Fe_(0.33)Mn_(0.67)O nanoparticles during the discharge/charge cycles. Moreover, the presence of metallic Fe enhances the conductivity and the electrochemical activity, which accelerates the electrochemical reactions. Therefore, reasonable design of microstructure and compositions of functional nanocomposites is the key to obtain ideal electrochemical properties.

Achieving ultrahigh electrocatalytic NH_(3) yield rate on Fe-doped Bi_(2)WO_(6) electrocatalyst

NH_(3),derived from electrocatalytic nitrogen reduction reaction(NRR),is promising to satisfy the need of food production and serve as a carbon-free liquid energy carrier in the near future.Yet major challenges remain in enhancing NH_(3) yield rate and conversion efficiency of available electrocatalysts.This work achieved an ultrahigh electrocatalytic NH_(3)yield rate on the_(0.50)Fe-Bi_(2)W0_(6) catalyst by a facile Fe-doped strategy.Up to 289μg·h^(-1)·mg_(cat)^(-1) of NH_(3) formation rate was obtained at-0.75 V vs.RHE,which was reliably quantized by indophenol blue and ^(1)H NMR methods.The impressive result is an order of magnitude higher than that of the reported Fe-and Bi-based catalysts,even more superior than the result of single atom Ru catalyst.The key of the outstanding NRR behaviors on the_(0.50)Fe-Bi_(2)W0_(6) catalyst is the significant hydrogen evolution reaction(HER)suppression and the synergy between Bi and Fe,which can effectively modulate the electron distribution and accelerate the electron transport.This work endows a new insight to further explore the high-performance electrocatalysts toward NRR.