Chitosan(CTS)was grafted onto the surface of amino‑functionalized silver chloride silicon dioxide(AgCl@SiO_(2)‑NH_(2))cores to obtain AgCl@SiO_(2)/CTS hybrid nanoparticles.The as‑obtained AgCl@SiO_(2)/CTS nanoparticle...Chitosan(CTS)was grafted onto the surface of amino‑functionalized silver chloride silicon dioxide(AgCl@SiO_(2)‑NH_(2))cores to obtain AgCl@SiO_(2)/CTS hybrid nanoparticles.The as‑obtained AgCl@SiO_(2)/CTS nanoparticles were chlorinated by NaClO solution to get AgCl@SiO_(2)/CTS‑based chloramine nano‑hybrid materials,denoted as AgCl@SiO_(2)/CTS‑Cl.A transmission electron microscope was used to observe the morphology of the as‑prepared samples AgCl@SiO_(2)/CTS and AgCl@SiO_(2)/CTS‑Cl.At the same time,an X‑ray diffractometer and an infrared spectroscope were utilized to characterize their crystal and chemical structures.Besides,ζpotentials were measured to elucidate the surface modification of AgCl nanoparticles by—NH_(2),the antibacterial mechanism of AgCl@SiO_(2)/CTS‑Cl was investigated by scanning electron microscopy,and Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were used as the to‑be‑tested strains to evaluate the antimicrobial activity of samples AgCl@SiO_(2)/CTS and AgCl@SiO_(2)/CTS‑Cl.Findings demonstrate that sample AgCl@SiO_(2)/CTS exhibits a chain‑like structure ascribed to the interaction between—NH_(2),and each AgCl@SiO_(2)/CTS hybrid nanoparticle contains several AgCl cores.In the meantime,sample AgCl@SiO_(2)/CTS‑Cl exhibits excellent antibacterial activity against E.coli and S.aureus,which is attributed to the synergistic antibacterial effect of Ag^(+)and Cl^(-).Sample AgCl@SiO_(2)/CTS‑Cl with a dosage of 640.00μg·mL^(-1) could completely kill the two kinds of tested bacteria in 12 h of incubation;it retains a high antibacterial efficiency even after 10 cycles of antibacterial tests.展开更多
Attaining the selective oxidation of isochroman into isochromanone in a molecular oxygen(O_(2))environment without any additives,via a heterogeneous oxidation process,is highly desirable and challenging work.Herein,we...Attaining the selective oxidation of isochroman into isochromanone in a molecular oxygen(O_(2))environment without any additives,via a heterogeneous oxidation process,is highly desirable and challenging work.Herein,we prepare two mixed-addendum polyoxometalate-based coordination polymers of the general formula[H_(x)M_(1-x)(i-PrIm)_(4)][H_(2)N(CH_(3))_(2)]_(4)[HPMo_(8)V_(6)O_(42)](M=Co 1,Ni,2;i-PrIm=1-isopropyl-1H-imidazole).Needing no additives,they can catalyze the selective oxidation of isochroman to isochromanone with O_(2)as an oxidant,with yields of 91.5%(1)and 46.8%(2),respectively.Mechanistic studies indicate that the excellent performance of catalyst 1 is attributed to the synergistic operation of[Co(i-Pr-Im)_(4))]complex and PMo_(8)V_(6)unit,and that the catalytic reaction is a radical pathway involving superoxide radicals.Additionally,the catalyst 1 can be recycled and reused at least four times with uncompromised performance.These results provide fundamental guidelines for designing efficient and multi-site heterogeneous catalysts for the selective oxidation of benzyl C(sp^(3))-H bonds by activating O_(2).展开更多
The synergistic effect of low Gd+Mn additions on the evolution of microstructure and mechanical properties of Mg−xGd−0.8Mn alloy was investigated.Gd addition shows a strong grain refinement effect on the extruded Mg−x...The synergistic effect of low Gd+Mn additions on the evolution of microstructure and mechanical properties of Mg−xGd−0.8Mn alloy was investigated.Gd addition shows a strong grain refinement effect on the extruded Mg−xGd−0.8Mn alloy,and leads to a continuous decrease in the area fraction of basal texture grains and the corresponding maximum density of texture components.However,the maximum density of the basal texture components grows abruptly as Gd content increases to 6 wt.%.When the Gd content is below 6 wt.%,the asymmetry of the tensile and compressive yield of the alloy is negatively correlated to the Gd content due to grain refinement and texture weakening effects.Besides,the contribution of grain refinement to higher alloy yield strength is more significant than that of grain orientation.Compared with the extruded Mg−xGd alloy,the extruded Mg−xGd−0.8Mn alloy shows a lower limit composition point that corresponds to solid solution strengthening and plasticizing effect(2 wt.%and 4 wt.%).Finally,the trend of basal slip and prismatic slip resistance variations of the extruded Mg−xGd−0.8Mn alloys was predicted.展开更多
Electrodeposition of acid copper plating on mild steel substrate is tedious due to the galvanic displacement reaction ofcopper on mild steel.This can be avoided by using a proper complexing agent,because the complexin...Electrodeposition of acid copper plating on mild steel substrate is tedious due to the galvanic displacement reaction ofcopper on mild steel.This can be avoided by using a proper complexing agent,because the complexing agent tuned the potential ofnoble direction to less noble direction by complex formation.In this paper,environment friendly electrodeposition of copper fromnon-cyanide electrolyte using sodium gluconate as complexing agent was investigated in alkaline medium.The effects of additivessuch as1,2,3-benzotriazole,sodium lauryl sulphate,PEG8000and saccharin were studied.These additives are found to reduce thegrain size,grain boundaries and improve surface morphology of the copper deposits.Also they improve the throwing power of thedepositing electrolytes and hardness of deposits.The electrodeposited copper coatings were characterized by X-ray diffractiontechnique.XRD results indicate that the electrodeposited copper shows polycrystalline and face centered cubic structure.The crystalsize was calculated by XRD and AFM analysis.Among these additives studied,the mixture of benzotriazole and sodium laurylsulphate acts as the best additive.A uniform pore-free surface observed under SEM and AFM results reveal the grain refining broughtabout by the additives.展开更多
The major solving ways for the material wear are surface modification and lubrication. Currently, the researches at home and abroad are all limited to the single study of either nano-lubricating oil additive or electr...The major solving ways for the material wear are surface modification and lubrication. Currently, the researches at home and abroad are all limited to the single study of either nano-lubricating oil additive or electroless deposited coating. The surface coating has high hardness and high wear resistance, however, the friction reduction performance of the coating with high hardness is not good, the thickness of the coating is limited, and the coating can not regenerate after wearing. The nano-lubricating additives have good tribological performance and self-repair function, but under heavy load, the self-repair rate to the worn surface with the nano-additives is smaller than the wearing rate of the friction pair. To solve the above problems, the Ni-W-P alloy coating and deposition process with excellent anti-wear, and suitable for industrial application were developed, the optimum bath composition and process can be obtained by studying the influence of the bath composition, temperature and PH value to the deposition rate and the plating solution stability. The tribological properties as well as anti-wear and friction reduction mechanism of wear self-repair nano-ceramic lubricating additives are also studied. The ring-block abrasion testing machine and energy dispersive spectrometer are used to explore the internal relation between the coating and the nano-lubricating oil additives, and the tribology mechanism, to seek the synergetic effect between the two. The test results show that the wear resistance of Ni-W-P alloy coating （with heat treatment and in oil with nano-ceramic additives） has increased hundreds times than 45 steel as the metal substrate in basic oil, the friction reduction performance is improved. This research breaks through the bottleneck of previous separate research of the above-mentioned two methods, and explores the combination use of the two methods in industrial field.展开更多
Background: The radiosensitizing effect of Photofrin II has been demonstrated in vitro and in animal models, even in tumor models known to be highly radioresistant, such as glioblastoma and bladder carcinoma. Radio-ad...Background: The radiosensitizing effect of Photofrin II has been demonstrated in vitro and in animal models, even in tumor models known to be highly radioresistant, such as glioblastoma and bladder carcinoma. Radio-adaptive doses are also known to lead to an augmented cell or tissue reaction. The aim of this study was to investigate potential synergistic or additive effects when combining the two methods in vitro for an improved therapeutic concept in bladder cancer. Material and Methods: RT4 human bladder carcinoma cell line and HCV29 human bladder epithelium cells were seeded and incubated with various concentrations of Photofrin II. The cells were additionally irradiated with ionizing radiation (0.05 Gy/2 Gy/0.05 Gy + 2 Gy). Cells without Photofrin II incubation and irradiation served as controls. The cell survival was evaluated. Results: The survival rate of both cell lines, RT4 and HCV29, did not differ significantly when incubated with a non-toxic concentration of Photofrin II and exposed to a pre-irradiation dose of 0.05 Gy prior to the 2 Gy radiation fraction, compared to cells exposed to Photofrin II plus a 2 Gy ionizing radiation. Conclusion: The combination of both methods did neither demonstrate a synergistic or additive effect nor did it lead to a negative influence of both modulating factors in an in vitro setting.展开更多
Autumn rain in western China(ARWC) is a unique and significant precipitation phenomenon that occurs during the summer-to-winter transition of the atmospheric circulation. Using the fifth generation of global climate a...Autumn rain in western China(ARWC) is a unique and significant precipitation phenomenon that occurs during the summer-to-winter transition of the atmospheric circulation. Using the fifth generation of global climate and weather reanalysis data from the European Centre for Medium-Range Weather Forecasts and CN05.1 grid precipitation data, this study examined the anomalous characteristics and mechanisms of ARWC by combining the synergistic effect of the westerly jet and meridional wind. Over the past 60 years, ARWC has exhibited significant interdecadal and interannual variations, as well as a north-south seesaw pattern. The westerly jet index(meridional wind index) exhibited a negative(positive) correlation with precipitation in the northern autumn rain zone(NARZ), and a positive(negative) correlation with precipitation in the southern autumn rain zone(SARZ). The coupling of a weak meridional southerly wind with a southward westerly jet and a strong meridional southerly wind with a northward westerly jet are the two primary modes that synergistically influence the ARWC. These synergistic effects cause significant atmospheric changes throughout the troposphere. The contrasting circulation structure, temperature advection, vertical motion, and water vapor flux contributed to the opposite precipitation anomalies observed in the NARZ and SARZ. A new comprehensive index that reflects the coupled synergistic effect is proposed to characterize the anomalous changes in ARWC. This study improves the understanding of the anomalous characteristics and mechanisms of ARWC.展开更多
As a key low-carbon energy source,nuclear power plays a vital role in the global transition toward sustainable energy.Photocatalytic uranium extraction from seawater(UES)offers a promising solution to ensure long-term...As a key low-carbon energy source,nuclear power plays a vital role in the global transition toward sustainable energy.Photocatalytic uranium extraction from seawater(UES)offers a promising solution to ensure long-term uranium supply but is challenged by ultra-low uranium concentrations and ion interference.To overcome these issues,we design three diketopyrrolopyrrole-based covalent organic frameworks(COFs)via a synergisticπ-extended lock and carboxyl-functionalized anchor molecular engineering strategy.Among them,TPy-DPP-COF features a covalently lockedπ-conjugated structure that enhances planarity,optimizes energy alignment,and minimizes exciton binding energy,thereby promoting charge transfer and suppressing recombination.Concurrently,carboxyl groups enable uranyl-specific coordination and create local electric fields to facilitate charge separation.These features contribute to the outstanding performance of TPy-DPP-COF,which achieves a high uranium adsorption capacity of 16.33 mg g−1 in natural seawater under irradiation,with only 29.3%capacity loss after 10 cycles,surpassing industrial benchmarks.Density functional theory(DFT)calculations and experimental studies reveal a synergistic photocatalysis-adsorption pathway,with DPP units acting as active sites for uranium reduction.This work highlights a molecular design strategy for developing efficient COF-based photocatalysts for practical marine uranium recovery.展开更多
Binuclear complexes have attracted extensive attention in fields such as catalysis because of their likely bimetallic synergistic effect;however,the mechanism and factors influencing this synergism remain unclear.In t...Binuclear complexes have attracted extensive attention in fields such as catalysis because of their likely bimetallic synergistic effect;however,the mechanism and factors influencing this synergism remain unclear.In this work,six bis-β-ketoimine binuclear titanium complexes4a-4f containing different alkylthio sidearms and configurations were synthesized and characterized by nuclear magnetic resonance hydrogen spectrum(~1H-NMR),nuclear magnetic resonance carbon spectrum(^(13)C-NMR),Fourier transform infrared spectrum(FTIR),and elemental analysis.The intermetallic distances of isomeric complexes 4a,4d,4e and 4f determined through density functional theory(DFT)optimization were in the order 4a<4d<4e<4f and were found to significantly influence the catalytic performance for ethylene(co)polymerization.These complexes could efficiently catalyze ethylene polymerization and ethylene/1-hexene or ethylene/1-octene copolymerization with high activity to produce highmolecular-weight ethylene homo-and co-polymers.Among the three binuclear titanium complexes 4a-4c with similar structures but different lengths of alkylthio sidearms,complex 4a,which contained the shortest methylthio sidearm,exhibited the highest activity for ethylene polymerization and copolymerization with 1-hexene or 1-octene.Additionally,for ethylene/1-hexene or ethylene/1-octene copolymerization,it showed the highest comonomer incorporation compared with propylthio(4b)and octylthio(4c)derivatives because of the smaller steric hindrance of the methyl group in 4a and the more open coordination space for vinyl monomers.Furthermore,among the isomeric complexes 4a,4d,4e and4f,complex 4a with the shortest bimetallic distance also exhibited the highest activity towards ethylene(co)polymerization,and the highest 1-hexene or 1-octene incorporation in comparison with its regioisomeric counterparts 4d,4e and p-phenyl-bridged analog 4f,owing to a more appropriate bimetallic distance that is conducive to a synergistic effect.展开更多
The role of catalysts in enhancing the hydrogen storage kinetics of the Mg/MgH_(2)system is pivotal.However,the exploration of efficient catalysts and the underlying principles of their design remain both a prominent ...The role of catalysts in enhancing the hydrogen storage kinetics of the Mg/MgH_(2)system is pivotal.However,the exploration of efficient catalysts and the underlying principles of their design remain both a prominent focus and a significant challenge in current research.In this study,we present a bimetallic oxide of Bi_(2)Ti_(2)O_(7)hollow sphere as a highly effective catalyst for MgH_(2).As a result,the Bi_(2)Ti_(2)O_(7)-catalyzed Mg/MgH_(2)system lowers the hydrogen desorption initiation temperature to 194.3℃,reduces the peak desorption temperature to 245.6℃,decreases the dehydrogenation activation energy to 82.14 kJ·mol^(−1),and can absorb 5.4 wt.%of hydrogen within 60 s at 200℃,demonstrating outstanding hydrogen ab/desorption kinetics,compared to pure MgH_(2).Additionally,it can maintain a high hydrogen capacity of 5.2 wt.%,even after 50 dehydrogenation cycles,showing good cycle stability.The characterization results show that the high-valent Bi and Ti in Bi_(2)Ti_(2)O_(7)are reduced to their low-valent or even zero-valent metallic states during the dehydrogenation and hydrogenation process,thus establishing an in-situ multivalent and multi-element catalytic environment.Density functional theory calculations further reveal that the synergistic effects between Bi and Ti in the Bi-Ti mixed oxide facilitate the cleavage of Mg-H bonds and lower the kinetic barrier for the dissociation of hydrogen molecules,thereby substantially enhancing the kinetics of the Mg/MgH_(2)system.This study presents a strategic method for developing efficient catalysts for hydrogen storage materials by harnessing the synergistic effects of metal elements.展开更多
The introduction of metal single atoms(SAs)and nanoparticles(NPs)are effective approaches to mod-ify electronic configuration of semiconductors,whereas recognizing the synergistic effects of metal SAs and NPs are stil...The introduction of metal single atoms(SAs)and nanoparticles(NPs)are effective approaches to mod-ify electronic configuration of semiconductors,whereas recognizing the synergistic effects of metal SAs and NPs are still challenging in photocatalytic water purification.Herein,a general strategy is achieved by subsequentially anchoring Fe SAs and Fe NPs in graphitic carbon nitride.The modification of Fe SAs and Fe NPs improves the energy band structure and constructs a gradient charge polarization,directly expanding the optical absorption range and facilitating the efficient separation and transfer of charge car-riers.With the assistance of the gradient charge polarization,pollutants are readily oxidated by h+,which strengthens the continuous reduction of O2 on Fe NPs for pollutant oxidation in water.This work rein-forces the synergistic effect of SAs and NPs on electronic configuration modulation at the atomic level,which exhibits great potential for the construction of an efficient and sustainable water purification sys-tem.展开更多
Bulk metallic glasses(BMGs)are typically characterized by high strength and elasticity.However,they generally demonstrate a deficiency in plastic deformation capability at room temperatures.In this work,Cu_(50-x)Zr_(4...Bulk metallic glasses(BMGs)are typically characterized by high strength and elasticity.However,they generally demonstrate a deficiency in plastic deformation capability at room temperatures.In this work,Cu_(50-x)Zr_(46)Al4Agx(x=0,1,2,3,4)alloys were prepared by arc melting and copper mold casting to investigate their structure,glass-forming ability,and mechanical properties.The results show that the addition of Ag can increase the parameter of DTx and g in Cu_(50)Zr_(46)Al_(4)alloy by 116%and 1.5%respectively,effectively enhancing its thermal stability and glass-forming ability.Compressive fracture tests reveal that the addition of Ag can significantly improve the yield strength,ultimate strength,and plasticity of the Cu_(50)Zr_(46)Al_(4)alloy.Specifically,with the Ag addition of 1 at.%,the alloy’s ultimate strength and plasticity increased by 71.8%and 21 times,respectively.Furthermore,the introduction of Ag can effectively control the free volume content in the Cu_(50)Zr_(46)Al_(4)alloy,thereby tuning the hardness of the material.This work provides valuable insights into improving the mechanical performance of BMGs through micro-alloying approaches.展开更多
The thermal conversion process known as biomass gasification has the potential to produce environmentally friendly fuels such as hydrogen.However,tar generation during the gasification remains an issue,affecting opera...The thermal conversion process known as biomass gasification has the potential to produce environmentally friendly fuels such as hydrogen.However,tar generation during the gasification remains an issue,affecting operational efficiency and environmental health.Biochar has been confirmed as an inexpensive and efficient catalyst for tar removal.The challenge lies in creating a highly reactive biochar which can be applied for different types of biomass with varying properties.This review discusses the factors that affect biochar’s reactivity as a catalyst for tar reforming.Additionally,incorporating biochar into a gasification scenario with raw biomass offers a practical solution by leveraging the synergistic behavior.However,this synergy could be either positive or negative:the positive synergy enhances tar removal while the negative synergy has the opposite effect.The numerous factors affecting the results of gasification are presented in this review.It is concluded that the positive synergistic effect resulted from the balance between the available reactants from biomass and biochar,the optimal gas flowrate and the active sites on the carbon surface.Understanding these interactions is crucial for optimizing biochar performance for tar removal.Ultimately,this research provides insights into biochar’s role in biomass gasification and suggests improvements for future studies to enhance the feasibility of biomass gasification with the assistance of biochar.展开更多
The antioxidant and anti-wrinkle firming effects of a combination of vitamin C(Vc)and black Ganoderma lucidum extract was evaluted.Through the DPPH radical scavenging model and elastase inhibition model,this research ...The antioxidant and anti-wrinkle firming effects of a combination of vitamin C(Vc)and black Ganoderma lucidum extract was evaluted.Through the DPPH radical scavenging model and elastase inhibition model,this research investigates the impact of these substances individually and in combination on antioxidant capabilities and anti-wrinkle firming effects.The results demonstrate that the combination of Vc and black Ganoderma lucidum extract exhibits significant antioxidant abilities at various concentrations,and is more effective than when each is used separately,indicating a synergistic interaction between them.Additionally,the combination also shows significant inhibition of elastase,suggesting potential applications in delaying the aging process of the skin.Furthermore,highperformance liquid chromatography(HPLC)was used to determine if reactions occur among the components of the mixture.The findings reveal that the concentration of Vc in the mixture is very close to the theoretical concentration and relatively stable,suggesting that the components function independently.A quantitative analysis using the Bliss independence model further confirms the synergistic effects of Vc and black Ganoderma lucidum extract at specific ratios,providing a scientific basis for the development of efficacious cosmetic products.展开更多
Organic additives with multiple functional groups have shown great promise in improving the performance and stability of perovskite solar cells.The functional groups can passivate undercoordinated ions to reduce nonra...Organic additives with multiple functional groups have shown great promise in improving the performance and stability of perovskite solar cells.The functional groups can passivate undercoordinated ions to reduce nonradiative recombination losses.However,how these groups synergistically affect the enhancement beyond passivation is still unclear.Specifically,isomeric molecules with different substitution patterns or molecular shapes remain elusive in designing new organic additives.Here,we report two isomeric carbazolyl bisphosphonate additives,2,7-Cz BP and 3,6-Cz BP.The isomerism effect on passivation and charge transport process was studied.The two molecules have similar passivation effects through multiple interactions,e.g.,P=O···Pb,P=O···H–N and N–H···I.2,7-CzBP can further bridge the perovskite crystallites to facilitates charge transport.Power conversion efficiencies(PCEs)of 25.88%and 21.04%were achieved for 0.09 cm^(2)devices and 14 cm^(2)modules after 2,7-Cz BP treatment,respectively.The devices exhibited enhanced operational stability maintaining 95%of initial PCE after 1000 h of continuous maximum power point tracking.This study of isomerism effect hints at the importance of tuning substitution positions and molecular shapes for organic additives,which paves the way for innovation of next-generation multifunctional aromatic additives.展开更多
Electrocatalytic water splitting for hydrogen production is a key approach to tackling the current energy crisis.Among the catalysts,the traditional Pd@C catalysts are remarkable for their efficiency in hydrogen evolu...Electrocatalytic water splitting for hydrogen production is a key approach to tackling the current energy crisis.Among the catalysts,the traditional Pd@C catalysts are remarkable for their efficiency in hydrogen evolution.However,the high cost and scarcity of Pd catalysts,as well as the instability caused by the corrosiveness of carbon-based substrates,hinder their large-scale application.To overcome this challenge,an effective strategy is to construct highly dispersed Pd single atoms to improve palladium utilization and choose more stable materials as supports.In this study,TiO_(2-x)carriers with abundant oxygen vacancies were prepared and loaded with Pd by photoreduction deposition.Adjusting the palladium content resulted in three forms of Pd-loaded TiO_(2-x):nanoparticles(Pd@TiO_(2-x)(6%,10%)),nanoclusters(Pd@TiO_(2-x)(3%))and single atoms(Pd@TiO_(2-x)(1.5%)).The oxygen vacancies improved the stability of the titanium dioxide materials by providing more active hydrogen adsorption sites and increasing the affinity of Pd for active hydrogen.Single atom loading increased the frequency of oxygen holes in the support and the high activity of monatomic Pd promoted the adsorption of active hydrogen and facilitated the formation of active hydrogen intermediates.The synergistic effect of single atoms and oxygen vacancies improved the stability and catalytic activity of the composite material.Pd@TiO_(2-x)(1.5%)showed outstanding performance in hydrogen evolution in an acidic medium with an overpotential of only 24 m V at a current density of 10 m A/cm^(2)and a low Tafel rise of 41.9 m V/dec.This study provides an effective strategy for the development of high-performance hydrogen evolution(HER)catalysts.展开更多
It is challenging to rationally construct synergistic charge-regulation of active sites and a lower energy barrier of the determining step for efficient oxygen reduction reaction(ORR).In this work,a novel catalyst(MnO...It is challenging to rationally construct synergistic charge-regulation of active sites and a lower energy barrier of the determining step for efficient oxygen reduction reaction(ORR).In this work,a novel catalyst(MnO_(2))_(cluster)/Fe,Mn-N-C with Fe-N_(4)O_(1) site coupled by MnO_(2) sub-nanometer clusters was successfully synthesized,which is attributed to the dicyanodiamine-glycine(DCD-Gly)dual-ligand effect.Specifically,the higher electrophilic index and the preferential coordination with Fe of N in DCD,and the chelating coordination of Gly with Mn.Experimental and theoretical calculation results indicate that preferential coordination of Fe with N atoms in DCD generates Fe-N_(4)O_(1) sites with axial oxygen coordination,while the coordination of Mn with Gly generates a large number of MnO_(2) sub-nanometer clusters.DFT calculations showed that axial oxygen altered the reaction-determining step of ORR at the FeN_(4)O_(1) site.Meanwhile,the MnO_(2) sub-nanoclusters further lowered the adsorption energy barriers of the reaction intermediates.This synergistic charge-regulation improved the ORR performance of(MnO_(2))_(cluster)/Fe,Mn-N-C(E_(1/2)=0.90 V).Meanwhile,(MnO_(2))_(cluster/)Fe,Mn-N-C catalyst also exhibits a discharge power density of 201 mW cm~(-2)in Zn-air batteries,which was much higher than the commercial Pt/C+RuO_(2).The strategy of ligand effect-driven construction provided a new idea for the electronic structure modulation of a monatomic catalyst.展开更多
Power cables are important pieces of equipment for energy transmission,but achieving a good balance between flame retardancy and mechanical properties of cable sheaths remains a challenge.In this work,a novel intumesc...Power cables are important pieces of equipment for energy transmission,but achieving a good balance between flame retardancy and mechanical properties of cable sheaths remains a challenge.In this work,a novel intumescent flame retardant(IFR)system containing silicone-containing macromolecular charring agent(Si-MCA)and ammonium polyphosphate(APP)was designed to synergistically improve the flame retardancy and mechanical properties of ethylene-butyl acrylate copolymer(EBA)composites.The optimal mass ratio of APP/Si-MCA was 3/1 in EBA composites(EBA/APP-Si-31),corresponding to the best flame retardancy with 31.2% of limited oxygen index(LOI),V-0 rating in UL-94 vertical burning test,and 76.4%reduction on the peak of heat release rate(PHRR)in cone calorimeter test.The enhancement mechanism was attributed to the synergistic effect of APP/Si-MCA during combustion,including the radical-trapping effect,the dilution effect of non-flammable gases,and the barrier effect of the intumescent char layer.Meanwhile,the tensile results indicated that EBA/APP-Si-31 also exhibited good mechanical properties with the addition of maleic anhydride-grafted polyethylene(PE-g-MA)as the compatibilizer.Thus,the APP/Si-MCA combination is an effective IFRs system for preparing high-performance EBA composites,and it will promote their applications as cable sheath materials.展开更多
Formation of multicomponent ceramics is one of the most promising strategies for enhancing the ablation resistance of ultra-high-temperature carbide ceramics(UHTCCs),while the effects of the elements are the foundatio...Formation of multicomponent ceramics is one of the most promising strategies for enhancing the ablation resistance of ultra-high-temperature carbide ceramics(UHTCCs),while the effects of the elements are the foundation.Here,we reported an elemental synergistic effect by investigating the ablation behavior of three components,including Zr_(1/2)Hf_(1/3)Ti_(1/6)C(ZHTi),Zr_(1/2)Hf_(1/3)Ta_(1/6)C(ZHTa),and Zr_(1/2)Hf_(1/3)Ti_(1/12)Ta_(1/12)C(ZHTT).Results indicate that the Ti-Ta synergistic effect enables ZHTT to exhibit a low recession rate(3.33μm/s)and linear expansion rate(2.00μm/s)of its oxide layer,attributable to enhanced self-healing capability and durable protection.During ablation,outward diffusion of Ti can heal the oxide layer,but results in severe consumption of UHTCCs.Although the low-volatility oxide formed by Ta can reduce the loss rate of the matrix,the negligible outward diffusion of Ta leads to the formation of a porous outer oxide layer.The co-addition of Ti and Ta simultaneously provides effective self-healing and low matrix recession,enabling enhanced ablation resistance of ZHTT.展开更多
Understanding the synergistic effect between ligands at the atomic level to control the catalytic selectivity of catalysts remains a significant challenge due to the complexity of ligand interactions and limitations i...Understanding the synergistic effect between ligands at the atomic level to control the catalytic selectivity of catalysts remains a significant challenge due to the complexity of ligand interactions and limitations in current analytical techniques.Herein,using precisely structured metal nanoclusters as models,we discovered that altering the electronegativity of substituents on donor thiolate ligands can modulate the bond dissociation energy of coordinated phosphine ligands on the clusters.This change leads to the selective dissociation of ligands during the catalytic process,thereby enabling control over catalytic selectivity with an abrupt increase in formate production from~0%to 23%.This work provides crucial insights into understanding ligand interactions on metal nanoparticle surfaces at the atomic level and lays the foundation for designing highly selective catalysts in the future.展开更多
文摘Chitosan(CTS)was grafted onto the surface of amino‑functionalized silver chloride silicon dioxide(AgCl@SiO_(2)‑NH_(2))cores to obtain AgCl@SiO_(2)/CTS hybrid nanoparticles.The as‑obtained AgCl@SiO_(2)/CTS nanoparticles were chlorinated by NaClO solution to get AgCl@SiO_(2)/CTS‑based chloramine nano‑hybrid materials,denoted as AgCl@SiO_(2)/CTS‑Cl.A transmission electron microscope was used to observe the morphology of the as‑prepared samples AgCl@SiO_(2)/CTS and AgCl@SiO_(2)/CTS‑Cl.At the same time,an X‑ray diffractometer and an infrared spectroscope were utilized to characterize their crystal and chemical structures.Besides,ζpotentials were measured to elucidate the surface modification of AgCl nanoparticles by—NH_(2),the antibacterial mechanism of AgCl@SiO_(2)/CTS‑Cl was investigated by scanning electron microscopy,and Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were used as the to‑be‑tested strains to evaluate the antimicrobial activity of samples AgCl@SiO_(2)/CTS and AgCl@SiO_(2)/CTS‑Cl.Findings demonstrate that sample AgCl@SiO_(2)/CTS exhibits a chain‑like structure ascribed to the interaction between—NH_(2),and each AgCl@SiO_(2)/CTS hybrid nanoparticle contains several AgCl cores.In the meantime,sample AgCl@SiO_(2)/CTS‑Cl exhibits excellent antibacterial activity against E.coli and S.aureus,which is attributed to the synergistic antibacterial effect of Ag^(+)and Cl^(-).Sample AgCl@SiO_(2)/CTS‑Cl with a dosage of 640.00μg·mL^(-1) could completely kill the two kinds of tested bacteria in 12 h of incubation;it retains a high antibacterial efficiency even after 10 cycles of antibacterial tests.
基金financially supported by the National Natural Science Foundation of China(Nos.22171122 and 22201123)Liaoning Revitalization Talents Program(No.XLYC 2007130)+1 种基金Fundamental Research Project(No.LJ212410148038)of the Educational Department of Liaoning ProvinceTalent Scientific Research Fund of Liaoning Petrochemical University(No.2016XJJL–019)。
文摘Attaining the selective oxidation of isochroman into isochromanone in a molecular oxygen(O_(2))environment without any additives,via a heterogeneous oxidation process,is highly desirable and challenging work.Herein,we prepare two mixed-addendum polyoxometalate-based coordination polymers of the general formula[H_(x)M_(1-x)(i-PrIm)_(4)][H_(2)N(CH_(3))_(2)]_(4)[HPMo_(8)V_(6)O_(42)](M=Co 1,Ni,2;i-PrIm=1-isopropyl-1H-imidazole).Needing no additives,they can catalyze the selective oxidation of isochroman to isochromanone with O_(2)as an oxidant,with yields of 91.5%(1)and 46.8%(2),respectively.Mechanistic studies indicate that the excellent performance of catalyst 1 is attributed to the synergistic operation of[Co(i-Pr-Im)_(4))]complex and PMo_(8)V_(6)unit,and that the catalytic reaction is a radical pathway involving superoxide radicals.Additionally,the catalyst 1 can be recycled and reused at least four times with uncompromised performance.These results provide fundamental guidelines for designing efficient and multi-site heterogeneous catalysts for the selective oxidation of benzyl C(sp^(3))-H bonds by activating O_(2).
基金National Natural Science Foundation of China(No.U2241231)National Key Research and Development Program of China(No.2021YFB3701100)+1 种基金Scientific Research Project of Jiangxi Provincial Department of Education,China(No.GJJ211038)Doctoral Research Project of Jinggangshan University,China(No.JZB2110)。
文摘The synergistic effect of low Gd+Mn additions on the evolution of microstructure and mechanical properties of Mg−xGd−0.8Mn alloy was investigated.Gd addition shows a strong grain refinement effect on the extruded Mg−xGd−0.8Mn alloy,and leads to a continuous decrease in the area fraction of basal texture grains and the corresponding maximum density of texture components.However,the maximum density of the basal texture components grows abruptly as Gd content increases to 6 wt.%.When the Gd content is below 6 wt.%,the asymmetry of the tensile and compressive yield of the alloy is negatively correlated to the Gd content due to grain refinement and texture weakening effects.Besides,the contribution of grain refinement to higher alloy yield strength is more significant than that of grain orientation.Compared with the extruded Mg−xGd alloy,the extruded Mg−xGd−0.8Mn alloy shows a lower limit composition point that corresponds to solid solution strengthening and plasticizing effect(2 wt.%and 4 wt.%).Finally,the trend of basal slip and prismatic slip resistance variations of the extruded Mg−xGd−0.8Mn alloys was predicted.
文摘Electrodeposition of acid copper plating on mild steel substrate is tedious due to the galvanic displacement reaction ofcopper on mild steel.This can be avoided by using a proper complexing agent,because the complexing agent tuned the potential ofnoble direction to less noble direction by complex formation.In this paper,environment friendly electrodeposition of copper fromnon-cyanide electrolyte using sodium gluconate as complexing agent was investigated in alkaline medium.The effects of additivessuch as1,2,3-benzotriazole,sodium lauryl sulphate,PEG8000and saccharin were studied.These additives are found to reduce thegrain size,grain boundaries and improve surface morphology of the copper deposits.Also they improve the throwing power of thedepositing electrolytes and hardness of deposits.The electrodeposited copper coatings were characterized by X-ray diffractiontechnique.XRD results indicate that the electrodeposited copper shows polycrystalline and face centered cubic structure.The crystalsize was calculated by XRD and AFM analysis.Among these additives studied,the mixture of benzotriazole and sodium laurylsulphate acts as the best additive.A uniform pore-free surface observed under SEM and AFM results reveal the grain refining broughtabout by the additives.
文摘The major solving ways for the material wear are surface modification and lubrication. Currently, the researches at home and abroad are all limited to the single study of either nano-lubricating oil additive or electroless deposited coating. The surface coating has high hardness and high wear resistance, however, the friction reduction performance of the coating with high hardness is not good, the thickness of the coating is limited, and the coating can not regenerate after wearing. The nano-lubricating additives have good tribological performance and self-repair function, but under heavy load, the self-repair rate to the worn surface with the nano-additives is smaller than the wearing rate of the friction pair. To solve the above problems, the Ni-W-P alloy coating and deposition process with excellent anti-wear, and suitable for industrial application were developed, the optimum bath composition and process can be obtained by studying the influence of the bath composition, temperature and PH value to the deposition rate and the plating solution stability. The tribological properties as well as anti-wear and friction reduction mechanism of wear self-repair nano-ceramic lubricating additives are also studied. The ring-block abrasion testing machine and energy dispersive spectrometer are used to explore the internal relation between the coating and the nano-lubricating oil additives, and the tribology mechanism, to seek the synergetic effect between the two. The test results show that the wear resistance of Ni-W-P alloy coating （with heat treatment and in oil with nano-ceramic additives） has increased hundreds times than 45 steel as the metal substrate in basic oil, the friction reduction performance is improved. This research breaks through the bottleneck of previous separate research of the above-mentioned two methods, and explores the combination use of the two methods in industrial field.
文摘Background: The radiosensitizing effect of Photofrin II has been demonstrated in vitro and in animal models, even in tumor models known to be highly radioresistant, such as glioblastoma and bladder carcinoma. Radio-adaptive doses are also known to lead to an augmented cell or tissue reaction. The aim of this study was to investigate potential synergistic or additive effects when combining the two methods in vitro for an improved therapeutic concept in bladder cancer. Material and Methods: RT4 human bladder carcinoma cell line and HCV29 human bladder epithelium cells were seeded and incubated with various concentrations of Photofrin II. The cells were additionally irradiated with ionizing radiation (0.05 Gy/2 Gy/0.05 Gy + 2 Gy). Cells without Photofrin II incubation and irradiation served as controls. The cell survival was evaluated. Results: The survival rate of both cell lines, RT4 and HCV29, did not differ significantly when incubated with a non-toxic concentration of Photofrin II and exposed to a pre-irradiation dose of 0.05 Gy prior to the 2 Gy radiation fraction, compared to cells exposed to Photofrin II plus a 2 Gy ionizing radiation. Conclusion: The combination of both methods did neither demonstrate a synergistic or additive effect nor did it lead to a negative influence of both modulating factors in an in vitro setting.
基金National Natural Science Foundation of China(42030611)Second Tibetan Plateau Scientific Expedition and Research (STEP) Program (2019QZKK0103)。
文摘Autumn rain in western China(ARWC) is a unique and significant precipitation phenomenon that occurs during the summer-to-winter transition of the atmospheric circulation. Using the fifth generation of global climate and weather reanalysis data from the European Centre for Medium-Range Weather Forecasts and CN05.1 grid precipitation data, this study examined the anomalous characteristics and mechanisms of ARWC by combining the synergistic effect of the westerly jet and meridional wind. Over the past 60 years, ARWC has exhibited significant interdecadal and interannual variations, as well as a north-south seesaw pattern. The westerly jet index(meridional wind index) exhibited a negative(positive) correlation with precipitation in the northern autumn rain zone(NARZ), and a positive(negative) correlation with precipitation in the southern autumn rain zone(SARZ). The coupling of a weak meridional southerly wind with a southward westerly jet and a strong meridional southerly wind with a northward westerly jet are the two primary modes that synergistically influence the ARWC. These synergistic effects cause significant atmospheric changes throughout the troposphere. The contrasting circulation structure, temperature advection, vertical motion, and water vapor flux contributed to the opposite precipitation anomalies observed in the NARZ and SARZ. A new comprehensive index that reflects the coupled synergistic effect is proposed to characterize the anomalous changes in ARWC. This study improves the understanding of the anomalous characteristics and mechanisms of ARWC.
基金the Young Elite Scientists Sponsorship Program by JXAST(2024QT11)the National Natural Science Foundation of China(22465001,22309003)the Jiangxi Provincial Natural Science Foundation(20232BAB203042,20242BAB22002).
文摘As a key low-carbon energy source,nuclear power plays a vital role in the global transition toward sustainable energy.Photocatalytic uranium extraction from seawater(UES)offers a promising solution to ensure long-term uranium supply but is challenged by ultra-low uranium concentrations and ion interference.To overcome these issues,we design three diketopyrrolopyrrole-based covalent organic frameworks(COFs)via a synergisticπ-extended lock and carboxyl-functionalized anchor molecular engineering strategy.Among them,TPy-DPP-COF features a covalently lockedπ-conjugated structure that enhances planarity,optimizes energy alignment,and minimizes exciton binding energy,thereby promoting charge transfer and suppressing recombination.Concurrently,carboxyl groups enable uranyl-specific coordination and create local electric fields to facilitate charge separation.These features contribute to the outstanding performance of TPy-DPP-COF,which achieves a high uranium adsorption capacity of 16.33 mg g−1 in natural seawater under irradiation,with only 29.3%capacity loss after 10 cycles,surpassing industrial benchmarks.Density functional theory(DFT)calculations and experimental studies reveal a synergistic photocatalysis-adsorption pathway,with DPP units acting as active sites for uranium reduction.This work highlights a molecular design strategy for developing efficient COF-based photocatalysts for practical marine uranium recovery.
基金financially supported by the National Natural Science Foundation of China(No.21172269)the Fundamental Research Funds for the Central Universities,SouthCentral Minzu University(No.CZH24005)。
文摘Binuclear complexes have attracted extensive attention in fields such as catalysis because of their likely bimetallic synergistic effect;however,the mechanism and factors influencing this synergism remain unclear.In this work,six bis-β-ketoimine binuclear titanium complexes4a-4f containing different alkylthio sidearms and configurations were synthesized and characterized by nuclear magnetic resonance hydrogen spectrum(~1H-NMR),nuclear magnetic resonance carbon spectrum(^(13)C-NMR),Fourier transform infrared spectrum(FTIR),and elemental analysis.The intermetallic distances of isomeric complexes 4a,4d,4e and 4f determined through density functional theory(DFT)optimization were in the order 4a<4d<4e<4f and were found to significantly influence the catalytic performance for ethylene(co)polymerization.These complexes could efficiently catalyze ethylene polymerization and ethylene/1-hexene or ethylene/1-octene copolymerization with high activity to produce highmolecular-weight ethylene homo-and co-polymers.Among the three binuclear titanium complexes 4a-4c with similar structures but different lengths of alkylthio sidearms,complex 4a,which contained the shortest methylthio sidearm,exhibited the highest activity for ethylene polymerization and copolymerization with 1-hexene or 1-octene.Additionally,for ethylene/1-hexene or ethylene/1-octene copolymerization,it showed the highest comonomer incorporation compared with propylthio(4b)and octylthio(4c)derivatives because of the smaller steric hindrance of the methyl group in 4a and the more open coordination space for vinyl monomers.Furthermore,among the isomeric complexes 4a,4d,4e and4f,complex 4a with the shortest bimetallic distance also exhibited the highest activity towards ethylene(co)polymerization,and the highest 1-hexene or 1-octene incorporation in comparison with its regioisomeric counterparts 4d,4e and p-phenyl-bridged analog 4f,owing to a more appropriate bimetallic distance that is conducive to a synergistic effect.
基金supported by the National Key Research and Development Program of China(No.2024YFB4007204,2022YFB4004301)the National Natural Science Founda-tion of China(Grant Nos.52477220,52301287,22005353)+2 种基金the Two-chain Integration Key Project of Shaanxi Province(2021LLRH-09)the Key Research and Development Program of Shaanxi Province(No.2024CY2-GJHX-44,2024CY2-GJHX-53,2024GX-ZDCYL-04-06)the Key Industrial Chain Technology Research Program of Xi’an city(23LL-RHZDZX0017).
文摘The role of catalysts in enhancing the hydrogen storage kinetics of the Mg/MgH_(2)system is pivotal.However,the exploration of efficient catalysts and the underlying principles of their design remain both a prominent focus and a significant challenge in current research.In this study,we present a bimetallic oxide of Bi_(2)Ti_(2)O_(7)hollow sphere as a highly effective catalyst for MgH_(2).As a result,the Bi_(2)Ti_(2)O_(7)-catalyzed Mg/MgH_(2)system lowers the hydrogen desorption initiation temperature to 194.3℃,reduces the peak desorption temperature to 245.6℃,decreases the dehydrogenation activation energy to 82.14 kJ·mol^(−1),and can absorb 5.4 wt.%of hydrogen within 60 s at 200℃,demonstrating outstanding hydrogen ab/desorption kinetics,compared to pure MgH_(2).Additionally,it can maintain a high hydrogen capacity of 5.2 wt.%,even after 50 dehydrogenation cycles,showing good cycle stability.The characterization results show that the high-valent Bi and Ti in Bi_(2)Ti_(2)O_(7)are reduced to their low-valent or even zero-valent metallic states during the dehydrogenation and hydrogenation process,thus establishing an in-situ multivalent and multi-element catalytic environment.Density functional theory calculations further reveal that the synergistic effects between Bi and Ti in the Bi-Ti mixed oxide facilitate the cleavage of Mg-H bonds and lower the kinetic barrier for the dissociation of hydrogen molecules,thereby substantially enhancing the kinetics of the Mg/MgH_(2)system.This study presents a strategic method for developing efficient catalysts for hydrogen storage materials by harnessing the synergistic effects of metal elements.
基金the National Natural Science Foundation of China(Nos.52100032 and 52350005)the Basic and Applied Basic Research Project of Guangzhou(Nos.2024A04J3679, 2024A03J0088)+2 种基金the Introduced Innovative Research and Development Team Project under the“The Pearl River Talent Recruitment Program”of Guangdong Province(No.2019ZT08L387)the Special Basic Research Fund for Central Public Research Institutes of China(No.PMzx703-202204-152)the Research Fund Program of Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology(No.2023B1212060016).
文摘The introduction of metal single atoms(SAs)and nanoparticles(NPs)are effective approaches to mod-ify electronic configuration of semiconductors,whereas recognizing the synergistic effects of metal SAs and NPs are still challenging in photocatalytic water purification.Herein,a general strategy is achieved by subsequentially anchoring Fe SAs and Fe NPs in graphitic carbon nitride.The modification of Fe SAs and Fe NPs improves the energy band structure and constructs a gradient charge polarization,directly expanding the optical absorption range and facilitating the efficient separation and transfer of charge car-riers.With the assistance of the gradient charge polarization,pollutants are readily oxidated by h+,which strengthens the continuous reduction of O2 on Fe NPs for pollutant oxidation in water.This work rein-forces the synergistic effect of SAs and NPs on electronic configuration modulation at the atomic level,which exhibits great potential for the construction of an efficient and sustainable water purification sys-tem.
基金supported by the National Natural Science Foun-dation of China(Grant Nos.12404228 and 52371148)the Science and Technology Research Program of Chongqing Ed-ucation Commission of China(Grant No.KJQN202200510).
文摘Bulk metallic glasses(BMGs)are typically characterized by high strength and elasticity.However,they generally demonstrate a deficiency in plastic deformation capability at room temperatures.In this work,Cu_(50-x)Zr_(46)Al4Agx(x=0,1,2,3,4)alloys were prepared by arc melting and copper mold casting to investigate their structure,glass-forming ability,and mechanical properties.The results show that the addition of Ag can increase the parameter of DTx and g in Cu_(50)Zr_(46)Al_(4)alloy by 116%and 1.5%respectively,effectively enhancing its thermal stability and glass-forming ability.Compressive fracture tests reveal that the addition of Ag can significantly improve the yield strength,ultimate strength,and plasticity of the Cu_(50)Zr_(46)Al_(4)alloy.Specifically,with the Ag addition of 1 at.%,the alloy’s ultimate strength and plasticity increased by 71.8%and 21 times,respectively.Furthermore,the introduction of Ag can effectively control the free volume content in the Cu_(50)Zr_(46)Al_(4)alloy,thereby tuning the hardness of the material.This work provides valuable insights into improving the mechanical performance of BMGs through micro-alloying approaches.
基金supported by JST Grant Number JPMJPF2104,Japan.Az Zahra and Alahakoon gratefully acknowledge MEXT of Japan for the scholarship.
文摘The thermal conversion process known as biomass gasification has the potential to produce environmentally friendly fuels such as hydrogen.However,tar generation during the gasification remains an issue,affecting operational efficiency and environmental health.Biochar has been confirmed as an inexpensive and efficient catalyst for tar removal.The challenge lies in creating a highly reactive biochar which can be applied for different types of biomass with varying properties.This review discusses the factors that affect biochar’s reactivity as a catalyst for tar reforming.Additionally,incorporating biochar into a gasification scenario with raw biomass offers a practical solution by leveraging the synergistic behavior.However,this synergy could be either positive or negative:the positive synergy enhances tar removal while the negative synergy has the opposite effect.The numerous factors affecting the results of gasification are presented in this review.It is concluded that the positive synergistic effect resulted from the balance between the available reactants from biomass and biochar,the optimal gas flowrate and the active sites on the carbon surface.Understanding these interactions is crucial for optimizing biochar performance for tar removal.Ultimately,this research provides insights into biochar’s role in biomass gasification and suggests improvements for future studies to enhance the feasibility of biomass gasification with the assistance of biochar.
文摘The antioxidant and anti-wrinkle firming effects of a combination of vitamin C(Vc)and black Ganoderma lucidum extract was evaluted.Through the DPPH radical scavenging model and elastase inhibition model,this research investigates the impact of these substances individually and in combination on antioxidant capabilities and anti-wrinkle firming effects.The results demonstrate that the combination of Vc and black Ganoderma lucidum extract exhibits significant antioxidant abilities at various concentrations,and is more effective than when each is used separately,indicating a synergistic interaction between them.Additionally,the combination also shows significant inhibition of elastase,suggesting potential applications in delaying the aging process of the skin.Furthermore,highperformance liquid chromatography(HPLC)was used to determine if reactions occur among the components of the mixture.The findings reveal that the concentration of Vc in the mixture is very close to the theoretical concentration and relatively stable,suggesting that the components function independently.A quantitative analysis using the Bliss independence model further confirms the synergistic effects of Vc and black Ganoderma lucidum extract at specific ratios,providing a scientific basis for the development of efficacious cosmetic products.
基金financially supported by the National Science Foundation of China(62474142)Natural Science Foundation of Shandong Province(No.ZR2024YQ070)。
文摘Organic additives with multiple functional groups have shown great promise in improving the performance and stability of perovskite solar cells.The functional groups can passivate undercoordinated ions to reduce nonradiative recombination losses.However,how these groups synergistically affect the enhancement beyond passivation is still unclear.Specifically,isomeric molecules with different substitution patterns or molecular shapes remain elusive in designing new organic additives.Here,we report two isomeric carbazolyl bisphosphonate additives,2,7-Cz BP and 3,6-Cz BP.The isomerism effect on passivation and charge transport process was studied.The two molecules have similar passivation effects through multiple interactions,e.g.,P=O···Pb,P=O···H–N and N–H···I.2,7-CzBP can further bridge the perovskite crystallites to facilitates charge transport.Power conversion efficiencies(PCEs)of 25.88%and 21.04%were achieved for 0.09 cm^(2)devices and 14 cm^(2)modules after 2,7-Cz BP treatment,respectively.The devices exhibited enhanced operational stability maintaining 95%of initial PCE after 1000 h of continuous maximum power point tracking.This study of isomerism effect hints at the importance of tuning substitution positions and molecular shapes for organic additives,which paves the way for innovation of next-generation multifunctional aromatic additives.
基金supported by the Key Project of Tianjin Natural Science Foundation(No.23JCZDJC00570)Special Funding of China Postdoctoral Science Foundation(No.2023T160268)+3 种基金China Postdoctoral Science Foundation(No.2023M741362)the National natural science foundation of China(Nos.22276209 and 21822608)Research Center for Eco-Environmental Science(No.RCEES-TDZ-2021-7)the support from the Youth Innovation Promotion Association of CAS(No.Y2021019)。
文摘Electrocatalytic water splitting for hydrogen production is a key approach to tackling the current energy crisis.Among the catalysts,the traditional Pd@C catalysts are remarkable for their efficiency in hydrogen evolution.However,the high cost and scarcity of Pd catalysts,as well as the instability caused by the corrosiveness of carbon-based substrates,hinder their large-scale application.To overcome this challenge,an effective strategy is to construct highly dispersed Pd single atoms to improve palladium utilization and choose more stable materials as supports.In this study,TiO_(2-x)carriers with abundant oxygen vacancies were prepared and loaded with Pd by photoreduction deposition.Adjusting the palladium content resulted in three forms of Pd-loaded TiO_(2-x):nanoparticles(Pd@TiO_(2-x)(6%,10%)),nanoclusters(Pd@TiO_(2-x)(3%))and single atoms(Pd@TiO_(2-x)(1.5%)).The oxygen vacancies improved the stability of the titanium dioxide materials by providing more active hydrogen adsorption sites and increasing the affinity of Pd for active hydrogen.Single atom loading increased the frequency of oxygen holes in the support and the high activity of monatomic Pd promoted the adsorption of active hydrogen and facilitated the formation of active hydrogen intermediates.The synergistic effect of single atoms and oxygen vacancies improved the stability and catalytic activity of the composite material.Pd@TiO_(2-x)(1.5%)showed outstanding performance in hydrogen evolution in an acidic medium with an overpotential of only 24 m V at a current density of 10 m A/cm^(2)and a low Tafel rise of 41.9 m V/dec.This study provides an effective strategy for the development of high-performance hydrogen evolution(HER)catalysts.
基金financially supported by the Major Science and Technology Projects in Yunnan Province(202402AG050008)the Science and Technology Plan Project of Yunnan Province(202303AK140022)+1 种基金the Scientific and Technological Project of Yunnan Precious Metals Laboratory(YPML-20240502003)the Analysis and Testing Foundation of Kunming University of Science and Technology。
文摘It is challenging to rationally construct synergistic charge-regulation of active sites and a lower energy barrier of the determining step for efficient oxygen reduction reaction(ORR).In this work,a novel catalyst(MnO_(2))_(cluster)/Fe,Mn-N-C with Fe-N_(4)O_(1) site coupled by MnO_(2) sub-nanometer clusters was successfully synthesized,which is attributed to the dicyanodiamine-glycine(DCD-Gly)dual-ligand effect.Specifically,the higher electrophilic index and the preferential coordination with Fe of N in DCD,and the chelating coordination of Gly with Mn.Experimental and theoretical calculation results indicate that preferential coordination of Fe with N atoms in DCD generates Fe-N_(4)O_(1) sites with axial oxygen coordination,while the coordination of Mn with Gly generates a large number of MnO_(2) sub-nanometer clusters.DFT calculations showed that axial oxygen altered the reaction-determining step of ORR at the FeN_(4)O_(1) site.Meanwhile,the MnO_(2) sub-nanoclusters further lowered the adsorption energy barriers of the reaction intermediates.This synergistic charge-regulation improved the ORR performance of(MnO_(2))_(cluster)/Fe,Mn-N-C(E_(1/2)=0.90 V).Meanwhile,(MnO_(2))_(cluster/)Fe,Mn-N-C catalyst also exhibits a discharge power density of 201 mW cm~(-2)in Zn-air batteries,which was much higher than the commercial Pt/C+RuO_(2).The strategy of ligand effect-driven construction provided a new idea for the electronic structure modulation of a monatomic catalyst.
基金supported by the National Natural Science Foundation of China(52473059)Taishan Scholar Constructive Engineering Foundation of Shandong Province(tsqn202103079)Key Research and Development Plan of Shandong Province(2024TSGC0264).
文摘Power cables are important pieces of equipment for energy transmission,but achieving a good balance between flame retardancy and mechanical properties of cable sheaths remains a challenge.In this work,a novel intumescent flame retardant(IFR)system containing silicone-containing macromolecular charring agent(Si-MCA)and ammonium polyphosphate(APP)was designed to synergistically improve the flame retardancy and mechanical properties of ethylene-butyl acrylate copolymer(EBA)composites.The optimal mass ratio of APP/Si-MCA was 3/1 in EBA composites(EBA/APP-Si-31),corresponding to the best flame retardancy with 31.2% of limited oxygen index(LOI),V-0 rating in UL-94 vertical burning test,and 76.4%reduction on the peak of heat release rate(PHRR)in cone calorimeter test.The enhancement mechanism was attributed to the synergistic effect of APP/Si-MCA during combustion,including the radical-trapping effect,the dilution effect of non-flammable gases,and the barrier effect of the intumescent char layer.Meanwhile,the tensile results indicated that EBA/APP-Si-31 also exhibited good mechanical properties with the addition of maleic anhydride-grafted polyethylene(PE-g-MA)as the compatibilizer.Thus,the APP/Si-MCA combination is an effective IFRs system for preparing high-performance EBA composites,and it will promote their applications as cable sheath materials.
基金supported by the National Natural Science Foundation of China grant numbers[52072410].
文摘Formation of multicomponent ceramics is one of the most promising strategies for enhancing the ablation resistance of ultra-high-temperature carbide ceramics(UHTCCs),while the effects of the elements are the foundation.Here,we reported an elemental synergistic effect by investigating the ablation behavior of three components,including Zr_(1/2)Hf_(1/3)Ti_(1/6)C(ZHTi),Zr_(1/2)Hf_(1/3)Ta_(1/6)C(ZHTa),and Zr_(1/2)Hf_(1/3)Ti_(1/12)Ta_(1/12)C(ZHTT).Results indicate that the Ti-Ta synergistic effect enables ZHTT to exhibit a low recession rate(3.33μm/s)and linear expansion rate(2.00μm/s)of its oxide layer,attributable to enhanced self-healing capability and durable protection.During ablation,outward diffusion of Ti can heal the oxide layer,but results in severe consumption of UHTCCs.Although the low-volatility oxide formed by Ta can reduce the loss rate of the matrix,the negligible outward diffusion of Ta leads to the formation of a porous outer oxide layer.The co-addition of Ti and Ta simultaneously provides effective self-healing and low matrix recession,enabling enhanced ablation resistance of ZHTT.
基金financially supported by the National Natural Science Foundation of China(Nos.22301155,22171156,21803001)Taishan Scholar Foundation of Shandong Province(China)+2 种基金the Natural Science Foundation of Shandong Province(No.ZR2023QB122)Shandong Province Excellent Youth Innovation TeamStartup Funds from Qingdao University of Science and Technology
文摘Understanding the synergistic effect between ligands at the atomic level to control the catalytic selectivity of catalysts remains a significant challenge due to the complexity of ligand interactions and limitations in current analytical techniques.Herein,using precisely structured metal nanoclusters as models,we discovered that altering the electronegativity of substituents on donor thiolate ligands can modulate the bond dissociation energy of coordinated phosphine ligands on the clusters.This change leads to the selective dissociation of ligands during the catalytic process,thereby enabling control over catalytic selectivity with an abrupt increase in formate production from~0%to 23%.This work provides crucial insights into understanding ligand interactions on metal nanoparticle surfaces at the atomic level and lays the foundation for designing highly selective catalysts in the future.
