This study aims to elucidate the formation mechanism of the goodwill measurement paradox and assess the impact of M&A synergy effects on goodwill measurement.Drawing upon empirical evidence from case studies,such ...This study aims to elucidate the formation mechanism of the goodwill measurement paradox and assess the impact of M&A synergy effects on goodwill measurement.Drawing upon empirical evidence from case studies,such as the Geely-Volvo acquisition,and broader empirical research on listed companies,the study seeks to offer practical guidance for refining industry-specific goodwill measurement standards within the registration system.Based on the"Institutional Environment-Synergy Effect-Goodwill Measurement"analytical framework,this study selects 528 non-same-control M&A samples of A-share listed companies from 2018 to 2023 as the research objects,and uses principal component analysis and a moderated mediation model to empirically test the impact of operational,financial,and management synergy effects on goodwill measurement,as well as the moderating roles of industry heterogeneity and policy changes.The conclusions are as follows:1.The current"difference method"in goodwill measurement shows a significant deviation,with non-synergistic premiums accounting for 21.5%,and reaching as high as 34.2%in technology-intensive industries.2.Operational,financial,and tax synergy effects all have a positive impact on goodwill measurement,with operational synergy being the most significant(coefficient 0.315***),amplifying to 0.471***in technology-intensive industries.Synergy effects are mainly transmitted through M&A premiums,with the mediating effect of operational synergy accounting for 42.8%.3.After the policy strengthening in 2019,the correlation between synergy effects and goodwill measurement increased by 12.5%,but technology-intensive industries still have a high impairment rate of 15.2%,indicating that policies have yet to fully eradicate the disparities in measurement risks among industries.4.This study is the first to quantify the moderating effects of policy changes and industry attributes on goodwill measurement,theoretically unveiling the core of the goodwill measurement paradox,and practically offering crucial guidance for refining relevant regulations,enhancing valuationtion systems,and formulating regulatory policies.展开更多
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. ...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.展开更多
Integrating single atoms and clusters into a unified catalytic system represents a novel strategy for enhancing catalytic performance.Compared to single-atom catalysts,those incorporating both single atoms and cluster...Integrating single atoms and clusters into a unified catalytic system represents a novel strategy for enhancing catalytic performance.Compared to single-atom catalysts,those incorporating both single atoms and clusters exhibit superior catalytic activity.However,the co-construction of these systems and the mechanisms of their catalytic efficacy remain challenging and poorly understood.In this study,we synthesized a Mn–N–C catalyst featuring MnY clusters and Mn single atoms via a straightforward two-step sintering method.Y doping facilitated the formation of Mn clusters and optimized the d-band center of Mn through a unique synergy effect,thereby reducing energy barriers and enhancing the reaction kinetics.Additionally,the electron-donating ability of Y single atoms promoted the formation of unsaturated Mn–N_(₃)coordination structures,resulting in excellent oxygen reduction reaction(ORR)performance.Consequently,the MnY/NC catalyst demonstrated a half-wave potential(E_(₁/₂))of 0.90 V and maintained stability in 0.1 M KOH,outperforming both Mn/NC and Pt/C.This work underscores the potential of rare earth metal doping in transition metals to create stable single-atom and cluster systems,effectively leveraging their synergy effect for superior catalytic performance and validating the concept of the“remote synergy effect”in heterogeneous catalysis.展开更多
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 ...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.展开更多
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 rel...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.展开更多
The synergy of single atoms(SAs)and nanoparticles(NPs)has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR);however,the rationalization of the SAs/NPs proportio...The synergy of single atoms(SAs)and nanoparticles(NPs)has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR);however,the rationalization of the SAs/NPs proportion remains one challenge for the catalyst design.Herein,a Ni2+-loaded porous poly(ionic liquids)(PIL)precursor synthesized through the free radical self-polymerization of the ionic liquid monomer,1-allyl-3-vinylimidazolium chloride,was pyrolyzed to prepare the Ni,N co-doped carbon materials,in which the proportion of Ni SAs and NPs could be facilely modulated by controlling the annealing temperature.The catalyst Ni-NC-1000 with a moderate proportion of Ni SAs and NPs exhibited high efficiency in the electrocatalytic conversion of CO_(2)into CO.Operando Ni K-edge X-ray absorption near-edge structure(XANES)spectra and theoretical calculations were conducted to gain insight into the synergy of Ni SAs and NPs.The charge transfer from Ni NPs to the surrounding carbon layer and then to the Ni SAs resulted in the electron-enriched Ni SAs active sites.In the electroreduction of CO_(2),the coexistence of Ni SAs and NPs strengthened the CO_(2)activation and the affinity towards the key intermediate of*COOH,lowering the free energy for the potential-determining*CO_(2)→*COOH step,and therefore promoted the catalysis efficiency.展开更多
Metal-organic frameworks(MOFs) provide great prospective in the photodegradation of pollutants. Nevertheless, the poor separation and recovery hamper their pilot-or industrial-scare applications because of their micro...Metal-organic frameworks(MOFs) provide great prospective in the photodegradation of pollutants. Nevertheless, the poor separation and recovery hamper their pilot-or industrial-scare applications because of their microcrystalline features. Herein, this challenge can be tackled by integrating Cu-MOFs into an alginate substrate to offer environmentally friendly, sustainable, facile separation, and high-performance MOF-based hydrogel photocatalysis platforms. The CuⅡ-MOF 1 and CuⅠ-MOF 2 were initially synthesized through a direct diffusion and single-crystal to single-crystal(SCSC) transformation method, respectively,and after the immobilization into alginate, more effective pollutant decontamination was achieved via the synergistic effect of the adsorption feature of hydrogel and in situ photodegradation of Cu-MOFs.Specifically, Cu-MOF-alginate composites present an improved and nearly completed Cr(Ⅵ) elimination at a short time of 15–25 min. Additionally, the congo red(CR) decolorization can be effectively enhanced in the presence of Cr(Ⅵ), and 1-alginate showed superior simultaneous decontamination efficiency of CR and Cr(Ⅵ) with 99% and 78%, respectively. Furthermore, Cu-MOF-alginate composites can maintain a high pollutant removal after over 10 continuous cycles(95% for Cr(Ⅵ) after 14 runs, and 90% for CR after 10runs). Moreover, the Cr(Ⅵ)/CR degradation mechanism for Cu-MOF-alginate composite was investigated.展开更多
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 effe...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.展开更多
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 ...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.展开更多
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 condensati...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.展开更多
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 ...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.展开更多
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 react...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.展开更多
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 speci...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.展开更多
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...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.展开更多
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...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.展开更多
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 ...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%.展开更多
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 wate...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].展开更多
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 inter...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.展开更多
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 t...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.展开更多
Defect engineering represents a potent strategy for the modification of electronic properties by introducing atomic vacancies in photocatalysts.However,the synergistic enhancement attributable to different types of at...Defect engineering represents a potent strategy for the modification of electronic properties by introducing atomic vacancies in photocatalysts.However,the synergistic enhancement attributable to different types of atomic vacancies within a heterojunction,as well as their underlying mechanisms,remains sparsely studied.Here,the flexible g-C_(3)N_(4)materials with varying nitrogen vacancies were prepared via a facile calcination method under different atmospheric conditions and then composited with CeO_(2)nanocubes to construct Z-scheme heterojunction.It was observed that CeO_(2)has abundant O vacancies,and the g-C_(3)N_(4)form tertiary nitrogen defects at the center of the heptazine units under an NH3 atmosphere treatment.The resulting enhancement in the interfacial built-in electric field,coupled with the synergistic effect of O and N vacancies within the Z-scheme heterojunction,has been demonstrated to significantly enhance charge transfer efficiency.This results in an optimized photoactivity with a H_(2)O_(2)generation rate of 2.01 mmol g^(-1)h^(-1).This work opens an avenue for constructing and optimizing the heterogeneous photocatalysts by defect engineering technology,and provides deep insight to understand the nature of vacancy engineering in designing effective catalysts for solar energy conversion.展开更多
文摘This study aims to elucidate the formation mechanism of the goodwill measurement paradox and assess the impact of M&A synergy effects on goodwill measurement.Drawing upon empirical evidence from case studies,such as the Geely-Volvo acquisition,and broader empirical research on listed companies,the study seeks to offer practical guidance for refining industry-specific goodwill measurement standards within the registration system.Based on the"Institutional Environment-Synergy Effect-Goodwill Measurement"analytical framework,this study selects 528 non-same-control M&A samples of A-share listed companies from 2018 to 2023 as the research objects,and uses principal component analysis and a moderated mediation model to empirically test the impact of operational,financial,and management synergy effects on goodwill measurement,as well as the moderating roles of industry heterogeneity and policy changes.The conclusions are as follows:1.The current"difference method"in goodwill measurement shows a significant deviation,with non-synergistic premiums accounting for 21.5%,and reaching as high as 34.2%in technology-intensive industries.2.Operational,financial,and tax synergy effects all have a positive impact on goodwill measurement,with operational synergy being the most significant(coefficient 0.315***),amplifying to 0.471***in technology-intensive industries.Synergy effects are mainly transmitted through M&A premiums,with the mediating effect of operational synergy accounting for 42.8%.3.After the policy strengthening in 2019,the correlation between synergy effects and goodwill measurement increased by 12.5%,but technology-intensive industries still have a high impairment rate of 15.2%,indicating that policies have yet to fully eradicate the disparities in measurement risks among industries.4.This study is the first to quantify the moderating effects of policy changes and industry attributes on goodwill measurement,theoretically unveiling the core of the goodwill measurement paradox,and practically offering crucial guidance for refining relevant regulations,enhancing valuationtion systems,and formulating regulatory policies.
基金supported by the 973 Program (No. 2014CB643503)the National Natural Science Foundation of China (Nos. 51625304, 51461165301)
文摘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.
基金supported by the National Natural Science Foundation of China(Youth Program,No.22309209)the Key Research and Development Program of Hunan Province(Grant No.2023GK2015)+3 种基金the Leading Telant in Science and Technological Innovation Program of Hunan Province,China(No.2022RC3049)the Tianshan Innovation Team Program of Xinjiang,China(No.2024D14001)the Natural Science Foundation of Hunan Province China(Grant No.2023JJ40709)This project was also supported by the State Key Laboratory of Powder Metallurgy,Central South University.
文摘Integrating single atoms and clusters into a unified catalytic system represents a novel strategy for enhancing catalytic performance.Compared to single-atom catalysts,those incorporating both single atoms and clusters exhibit superior catalytic activity.However,the co-construction of these systems and the mechanisms of their catalytic efficacy remain challenging and poorly understood.In this study,we synthesized a Mn–N–C catalyst featuring MnY clusters and Mn single atoms via a straightforward two-step sintering method.Y doping facilitated the formation of Mn clusters and optimized the d-band center of Mn through a unique synergy effect,thereby reducing energy barriers and enhancing the reaction kinetics.Additionally,the electron-donating ability of Y single atoms promoted the formation of unsaturated Mn–N_(₃)coordination structures,resulting in excellent oxygen reduction reaction(ORR)performance.Consequently,the MnY/NC catalyst demonstrated a half-wave potential(E_(₁/₂))of 0.90 V and maintained stability in 0.1 M KOH,outperforming both Mn/NC and Pt/C.This work underscores the potential of rare earth metal doping in transition metals to create stable single-atom and cluster systems,effectively leveraging their synergy effect for superior catalytic performance and validating the concept of the“remote synergy effect”in heterogeneous catalysis.
基金supported by the National Key R&D Program of China(2017YFA0700102)the National Natural Science Foundation of China(21573222,91545202,21802124,91945302 and 91845103)+6 种基金Dalian National Laboratory for Clean Energy(DNL180404)Dalian Institute of Chemical Physics(DICP DMTO201702)Dalian Outstanding Young Scientist Foundation(2017RJ03)Liaoning Revitalization Talents Program(XLYC1907099)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17020200)the financial support from CAS Youth Innovation Promotion(2015145)the financial support from the China Postdoctoral Science Foundation(2018M630307 and 2019T120220)。
文摘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.
基金supported by the National Key R&D Program of China (No.2017YFE0300406)National Natural Science Foundation of China (Nos. 11 975 272, 12 075 276, 11 375 234, 11 805 133 and 12 005 258).
文摘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.
基金National Natural Science Foundation of China(grants 22072065,22178162,and 22222806)Distinguished Youth Foundation of Jiangsu Province(grant BK20220053)Six talent peaks project in Jiangsu Province(grant JNHB-035)。
文摘The synergy of single atoms(SAs)and nanoparticles(NPs)has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR);however,the rationalization of the SAs/NPs proportion remains one challenge for the catalyst design.Herein,a Ni2+-loaded porous poly(ionic liquids)(PIL)precursor synthesized through the free radical self-polymerization of the ionic liquid monomer,1-allyl-3-vinylimidazolium chloride,was pyrolyzed to prepare the Ni,N co-doped carbon materials,in which the proportion of Ni SAs and NPs could be facilely modulated by controlling the annealing temperature.The catalyst Ni-NC-1000 with a moderate proportion of Ni SAs and NPs exhibited high efficiency in the electrocatalytic conversion of CO_(2)into CO.Operando Ni K-edge X-ray absorption near-edge structure(XANES)spectra and theoretical calculations were conducted to gain insight into the synergy of Ni SAs and NPs.The charge transfer from Ni NPs to the surrounding carbon layer and then to the Ni SAs resulted in the electron-enriched Ni SAs active sites.In the electroreduction of CO_(2),the coexistence of Ni SAs and NPs strengthened the CO_(2)activation and the affinity towards the key intermediate of*COOH,lowering the free energy for the potential-determining*CO_(2)→*COOH step,and therefore promoted the catalysis efficiency.
基金supported by the National Natural Science Foundation of China(Nos.22077099,22171223 and 22307102)the Innovation Capability Support Program of Shaanxi(Nos.2023-CX-TD-75 and 2022KJXX-32)+5 种基金the Technology Innovation Leading Program of Shaanxi(Nos.2023KXJ-209 and 2024QCYKXJ-142)the Natural Science Basic Research Program of Shaanxi(Nos.2023-JC-YB-141 and 2022JQ-151)the Key Research and Development Program of Shaanxi(No.2024GH-ZDXM-22)Young Talent Fund of Association for Science and Technology in Shaanxi,China(No.SWYY202206)the Shaanxi Fundamental Science Research Project for Chemistry&Biology(Nos.22JHZ010 and 22JHQ080)the Yan’an City Science and Technology Project(No.2022SLZDCY-002).
文摘Metal-organic frameworks(MOFs) provide great prospective in the photodegradation of pollutants. Nevertheless, the poor separation and recovery hamper their pilot-or industrial-scare applications because of their microcrystalline features. Herein, this challenge can be tackled by integrating Cu-MOFs into an alginate substrate to offer environmentally friendly, sustainable, facile separation, and high-performance MOF-based hydrogel photocatalysis platforms. The CuⅡ-MOF 1 and CuⅠ-MOF 2 were initially synthesized through a direct diffusion and single-crystal to single-crystal(SCSC) transformation method, respectively,and after the immobilization into alginate, more effective pollutant decontamination was achieved via the synergistic effect of the adsorption feature of hydrogel and in situ photodegradation of Cu-MOFs.Specifically, Cu-MOF-alginate composites present an improved and nearly completed Cr(Ⅵ) elimination at a short time of 15–25 min. Additionally, the congo red(CR) decolorization can be effectively enhanced in the presence of Cr(Ⅵ), and 1-alginate showed superior simultaneous decontamination efficiency of CR and Cr(Ⅵ) with 99% and 78%, respectively. Furthermore, Cu-MOF-alginate composites can maintain a high pollutant removal after over 10 continuous cycles(95% for Cr(Ⅵ) after 14 runs, and 90% for CR after 10runs). Moreover, the Cr(Ⅵ)/CR degradation mechanism for Cu-MOF-alginate composite was investigated.
基金supported by the National Natural Science Foundation of China(22078228)。
文摘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.
基金financially supported by the Key Program for International S&T Cooperation Projects of China(No.2017YFE0124300)National Natural Science Foundation of China(No.52171205,51971002 and 52171197)+1 种基金Scientific Research Foundation of Anhui Provincial Education Department(Nos.KJ2020ZD26,KJ2021A0360)Anhui Provincial Natural Science Foundation for Excellent Youth Scholars(No.2108085Y16).
文摘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.
文摘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.
文摘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.
基金the financial support from the Natural Science Foundation of Shandong Province(Nos.ZR2021QE096,ZR2021MB101,ZR2021ME113 and ZR2021ME177)。
文摘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.
文摘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.
基金supported by the National Natural Science Foundation of China (NSFC, Nos. 21901222, U1904215 and 21671170)Lvyangjinfeng Talent Program of Yangzhou+2 种基金the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)Program for Young Changjiang Scholars of the Ministry of Education,China (No. Q2018270)Natural Science Foundation of Jiangsu Province (No. BK20200044)。
文摘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.
基金National Natural Science Foundation of China,No.42371213Third Xinjiang Scientific Expedition Program,No.2021xjkk0900。
文摘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.
基金Funded by the Natural Science Foundation of Hubei Province (No.2007ABA028)
文摘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%.
基金financially supported by the Natural Science Foundation of Jiangxi Province of China (20192BAB213001)the Foundation of Jiangxi Educational Committee (GJJ180406)+2 种基金the Research Foundation for Advanced Talents of East China University of Technology (DHBK2018043)the National Natural Science Foundation of China (2187104721661001)。
文摘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].
基金supported by CREST project(Catalyst Design of Gold Clusters through Junction Effect with Metal oxides,Carbons,and Polymers)sponsored by Japan Science and Technology Agency(JST)~~
文摘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.
基金supported by National Natural Science Foundation of China(nos 12075037 and 22206013)。
文摘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.
基金financially supported by the Shaanxi Provin-cial Natural Science Basic Research Program(No.2023-JC-YB-457)the National Natural Science Foundation of China(Nos.52025061 and 52106270)+3 种基金the China Postdoctoral Science Foun-dation(No.2020M683472)the China Fundamental Research Funds for the Central Universitiessupported by the Zhuhai Innovation and Entrepreneurship Team Project(No.2120004000225)the Project of Shaanxi Provincial Science and Technology Innovation Team(No.2023-CX-TD-25).
文摘Defect engineering represents a potent strategy for the modification of electronic properties by introducing atomic vacancies in photocatalysts.However,the synergistic enhancement attributable to different types of atomic vacancies within a heterojunction,as well as their underlying mechanisms,remains sparsely studied.Here,the flexible g-C_(3)N_(4)materials with varying nitrogen vacancies were prepared via a facile calcination method under different atmospheric conditions and then composited with CeO_(2)nanocubes to construct Z-scheme heterojunction.It was observed that CeO_(2)has abundant O vacancies,and the g-C_(3)N_(4)form tertiary nitrogen defects at the center of the heptazine units under an NH3 atmosphere treatment.The resulting enhancement in the interfacial built-in electric field,coupled with the synergistic effect of O and N vacancies within the Z-scheme heterojunction,has been demonstrated to significantly enhance charge transfer efficiency.This results in an optimized photoactivity with a H_(2)O_(2)generation rate of 2.01 mmol g^(-1)h^(-1).This work opens an avenue for constructing and optimizing the heterogeneous photocatalysts by defect engineering technology,and provides deep insight to understand the nature of vacancy engineering in designing effective catalysts for solar energy conversion.
