A promising Co3O4/Cu O composite electrode material was successfully synthesized through a facile hydrothermal and calcination process. Effects of the surfactants hexadecyltrimethyl ammonium bromide（CTAB） and polyvi...A promising Co3O4/Cu O composite electrode material was successfully synthesized through a facile hydrothermal and calcination process. Effects of the surfactants hexadecyltrimethyl ammonium bromide（CTAB） and polyvinylpyrrolidone（PVP） on the morphology and electrochemical performance of the composite were investigated. Powder X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and nitrogen adsorption-desorption experiment were employed to characterize the microstructures and morphologies of the composite. Meanwhile, the electrochemical performances of the samples were studied using cyclic voltammetry（CV）, galvanostatic charge-discharge test and electrochemical impedance spectroscopy（EIS）. The results show that the porous Co3O4/Cu O-CTAB nanoplates own the best performance and exhibits a high specific capacitance of 398 F/g at 1 A/g with almost 100% capacitance retention over 2000 cycles, and it retains 90% of capacitance at 10 A/g.展开更多
Black nickel coatings have emerged as a research hotspot in materials science due to their excellent performance and broad application prospects.In this study,nickel-based black coatings were fabricated on low-carbon ...Black nickel coatings have emerged as a research hotspot in materials science due to their excellent performance and broad application prospects.In this study,nickel-based black coatings were fabricated on low-carbon steel substrates via photo-assisted electrodeposition.A systematic investigation was conducted on the effects of cerium ion concentration and nano-ceria(CeO_(2))particle content in the electrolyte on the coating properties,along with an analysis of the temporal evolution of coating’s corrosion resistance.When the cerium ion concentration in the electrolyte was 0.05 mol/L,the coating exhibited a uniform black appearance with a light absorption rate of 95%,an emissivity of 0.87,maximum impedance,and the lowest corrosion tendency,demonstrating optimal comprehensive performance.The coating prepared with a nano-ceria concentration of 6 g/L in the electrolyte exhibited an emissivity of 0.9,achieved a 5B adhesion grade(ASTM D3359-09),and demonstrated a one-order-of-magnitude reduction in corrosion current density compared to coatings fabricated without nano-ceria in the electrolyte.With prolonged storage time,the coating's impedance slightly increased,leading to improved corrosion resistance.展开更多
High-entropy oxides(HEOs)have emerged as a promising class of memristive materials,characterized by entropy-stabilized crystal structures,multivalent cation coordination,and tunable defect landscapes.These intrinsic f...High-entropy oxides(HEOs)have emerged as a promising class of memristive materials,characterized by entropy-stabilized crystal structures,multivalent cation coordination,and tunable defect landscapes.These intrinsic features enable forming-free resistive switching,multilevel conductance modulation,and synaptic plasticity,making HEOs attractive for neuromorphic computing.This review outlines recent progress in HEO-based memristors across materials engineering,switching mechanisms,and synaptic emulation.Particular attention is given to vacancy migration,phase transitions,and valence-state dynamics—mechanisms that underlie the switching behaviors observed in both amorphous and crystalline systems.Their relevance to neuromorphic functions such as short-term plasticity and spike-timing-dependent learning is also examined.While encouraging results have been achieved at the device level,challenges remain in conductance precision,variability control,and scalable integration.Addressing these demands a concerted effort across materials design,interface optimization,and task-aware modeling.With such integration,HEO memristors offer a compelling pathway toward energy-efficient and adaptable brain-inspired electronics.展开更多
Improving device efficiency is fundamental for advancing energy harvesting technology,particularly in systems designed to convert light energy into electrical output.In our previous studies,we developed a basic struct...Improving device efficiency is fundamental for advancing energy harvesting technology,particularly in systems designed to convert light energy into electrical output.In our previous studies,we developed a basic structure light pressure electric generator(Basic-LPEG),which utilized a layered configuration of Ag/Pb(Zr,Ti)O_(3)(PZT)/Pt/GaAs to generate electricity based on light-induced pressure on the PZT.In this study,we sought to enhance the performance of this Basic-LPEG by introducing Ag nanoparticles/graphene oxide(AgNPs/GO)composite units(NP-LPEG),creating upgraded harvesting device.Specifically,by depositing the AgNPs/GO units twice onto the Basic-LPEG,we observed an increase in output voltage and current from 241 mV and 3.1μA to 310 mV and 9.3μA,respectively,under a solar simulator.The increase in electrical output directly correlated with the intensity of the light pressure impacting the PZT,as well as matched the Raman measurements,finite-difference time-domain simulations,and COMSOL Multiphysics Simulation.Experimental data revealed that the enhancement in electrical output was proportional to the number of hot spots generated between Ag nanoparticles,where the electric field experienced substantial amplification.These results underline the effectiveness of AgNPs/GO units in boosting the light-induced electric generation capacity,thereby providing a promising pathway for high-efficiency energy harvesting devices.展开更多
The thermal decomposition characteristic of ammonium perchlorate(AP)represents a critical factor in determining the performance of solid propellants,which has aroused significant interest on the structure and performa...The thermal decomposition characteristic of ammonium perchlorate(AP)represents a critical factor in determining the performance of solid propellants,which has aroused significant interest on the structure and performance improvement of kinds of catalysts.In this study,bimetallic metal-organic frameworks(MOFs),such as CuCo-BTC(BTC=1,3,5-Benzenetricarboxylic acid,H_(3)BTC),CuNi-BTC,and CoNi-BTC,were synthesized by solvothermal(ST)and spray-drying(SD)methods,and then calcined at 400℃for 2 h to form metal oxides.The catalysts as well as their catalytic effects for AP decomposition were characterized by FTIR,XRD,SEM,XPS,TG,DSC,TG-IR,EIS,CV,and LSV.It was found that the rapid coordination of metal ions with ligands during spray drying may lead to catalytic structural defects,promoting the exposure of reactive active sites and increasing the catalytic active region.The results showed that the addition of 2 wt%binary transition metal oxides(BTMOs)as catalysts significantly reduced the high-temperature decomposition(HTD)temperature of AP and enhanced its heat release.Of particular significance is the observation that SD-CoNiO_(x),prepared by spray-drying,reduced the decomposition temperature of AP from 413.26℃(pure AP)to 306℃and enhanced the heat release from 256.79 J/g(pure AP)to 1496.82 J/g,while concomitantly reducing the activation energy by 42%.By analysing the gaseous products during the decomposition of AP+SD-CoNiO_(x)and AP+ST-CoNiO_(x),it was found that SD-CoNiO_(x)could significantly increase the content of high-valent nitrogen oxides during the AP decomposition reaction,which indicates that the BTMOs prepared by spray-drying in the reaction system are more conducive to accelerating the electron transfer in the thermal decomposition process of AP,and can provide a high concentration of reactive oxygen species that oxidize AP to high-valent nitrogen oxide-containing compounds.The present study shows that the structure selectivity of the spray-drying technique influences surfactant molecular arrangement on catalyst surfaces,resulting in their ability to promote higher electron transfer during the catalytic process.Therefore,BTMOs prepared by spray drying method have higher potential for application.展开更多
This study focused on improving the cathode performance of Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.15)O_(3-δ)(BSCN)-based perovskite materials through molybdenum(Mo)doping.Pure BSCN and Mo-modified-BSCN—Ea_(0.6)Sr_(0.4)Co_(0...This study focused on improving the cathode performance of Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.15)O_(3-δ)(BSCN)-based perovskite materials through molybdenum(Mo)doping.Pure BSCN and Mo-modified-BSCN—Ea_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.1)Mo_(0.05)O_(3-δ)(B S CNM_(0.05)),Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.05)Mo_(0.1)O_(3-δ)(BSCNM_(0.1)),and Ba_(0.6)Sr_(0.4)Co_(0.85)Mo_(0.15)O_(3-δ)(BSCM)—with Mo doping contents of 5mol%,10mol%,and15mol%,respectively,were successfully prepared using the sol-gel method.The effects of Mo doping on the crystal structure,conductivity,thermal expansion coefficient,oxygen reduction reaction(ORR)activity,and electrochemical performance were systematically evaluated using X-ray diffraction analysis,thermally induced characterization,electrochemical impedance spectroscopy,and single-cell performance tests.The results revealed that Mo doping could improve the conductivity of the materials,suppress their thermal expansion effects,and significantly improve the electrochemical performance.Surface chemical state analysis using X-ray photoelectron spectroscopy revealed that 5mol%Mo doping could facilitate a high adsorbed oxygen concentration leading to enhanced ORR activity in the materials.Density functional theory calculations confirmed that Mo doping promoted the ORR activity in the materials.At an operating temperature of 600℃,the BSCNM_(0.05)cathode material exhibited significantly enhanced electrochemical impedance characteristics,with a reduced area specific resistance of 0.048Ω·cm~2,which was lower than that of the undoped BSCN matrix material by 32.39%.At the same operating temperature,an anode-supported single cell using a BSCNM_(0.05)cathode achieved a peak power density of 1477 mW·cm^(-2),which was 30.71%,56.30%,and 171.50%higher than those of BSCN,BSCNM_(0.1),and B SCM,respectively.The improved ORR activity and electrochemical performance of BSCNM_(0.05)indicate that it can be used as a cathode material in low-temperature solid oxide fuel cells.展开更多
Oxide dispersion strengthened(ODS)alloys are extensively used owing to high thermostability and creep strength contributed from uniformly dispersed fine oxides particles.However,the existence of these strengthening pa...Oxide dispersion strengthened(ODS)alloys are extensively used owing to high thermostability and creep strength contributed from uniformly dispersed fine oxides particles.However,the existence of these strengthening particles also deteriorates the processability and it is of great importance to establish accurate processing maps to guide the thermomechanical processes to enhance the formability.In this study,we performed particle swarm optimization-based back propagation artificial neural network model to predict the high temperature flow behavior of 0.25wt%Al2O3 particle-reinforced Cu alloys,and compared the accuracy with that of derived by Arrhenius-type constitutive model and back propagation artificial neural network model.To train these models,we obtained the raw data by fabricating ODS Cu alloys using the internal oxidation and reduction method,and conducting systematic hot compression tests between 400 and800℃with strain rates of 10^(-2)-10 S^(-1).At last,processing maps for ODS Cu alloys were proposed by combining processing parameters,mechanical behavior,microstructure characterization,and the modeling results achieved a coefficient of determination higher than>99%.展开更多
Electrocatalytic nitric oxide(NO)reduction reaction(NORR)is a promising and sustainable process that can simultaneously realize green ammonia(NH3)synthesis and hazardous NO removal.However,current NORR performances ar...Electrocatalytic nitric oxide(NO)reduction reaction(NORR)is a promising and sustainable process that can simultaneously realize green ammonia(NH3)synthesis and hazardous NO removal.However,current NORR performances are far from practical needs due to the lack of efficient electrocatalysts.Engineering the lattice of metal-based nanomaterials via phase control has emerged as an effective strategy to modulate their intrinsic electrocatalytic properties.Herein,we realize boron(B)-insertion-induced phase regulation of rhodium(Rh)nanocrystals to obtain amorphous Rh_(4)B nanoparticles(NPs)and hexagonal close-packed(hcp)RhB NPs through a facile wet-chemical method.A high Faradaic efficiency(92.1±1.2%)and NH_(3) yield rate(629.5±11.0μmol h^(−1) cm^(−2))are achieved over hcp RhB NPs,far superior to those of most reported NORR nanocatalysts.In situ spectro-electrochemical analysis and density functional theory simulations reveal that the excellent electrocatalytic performances of hcp RhB NPs are attributed to the upshift of d-band center,enhanced NO adsorption/activation profile,and greatly reduced energy barrier of the rate-determining step.A demonstrative Zn-NO battery is assembled using hcp RhB NPs as the cathode and delivers a peak power density of 4.33 mW cm−2,realizing simultaneous NO removal,NH3 synthesis,and electricity output.展开更多
Electrochemical CO_(2) reduction reaction(CO_(2)RR),driven by renewable energy,offers a promising solution to mitigate increasing CO_(2) emissions and establish a carbon-neutral cycle.Copper is a highly selective and ...Electrochemical CO_(2) reduction reaction(CO_(2)RR),driven by renewable energy,offers a promising solution to mitigate increasing CO_(2) emissions and establish a carbon-neutral cycle.Copper is a highly selective and active catalyst for CO_(2)RR but suffers from structural reconstruction challenges.Hybrid organic/inorganic materials address these issues by offering customizable compositions and interfaces.Recently,Buonsanti’s team developed hybrid Cu@AlOx nanocrystals with tunable alumina shells via a colloidal atomic layer deposition approach,achieving stable and selective methane production during CO_(2)RR.Mechanistic studies reveal that the alumina shell stabilizes oxidized copper species through Cu^(2+)-O-Al motifs coordinated with AlO_(4) Lewis acid sites,reducing copper dissolution and structural reconstruction.This study provides key insights into the mechanism underlying stabilization,highlighting the critical role of Lewis acidity in preserving the structural integrity of the catalyst.This highlight review aims to inspire the development of other high-performance and stable catalysts through colloidal atomic layer deposition strategies.展开更多
Some active metal oxides(Al_(2)O_(3),TiO_(2),and Cr_(2)O_(3))were selected as dopants to the Al_(2)O_(3)-based ceramic shells for investment casting of K417G superalloy.The effects of dopant types and contents(0,2,5,a...Some active metal oxides(Al_(2)O_(3),TiO_(2),and Cr_(2)O_(3))were selected as dopants to the Al_(2)O_(3)-based ceramic shells for investment casting of K417G superalloy.The effects of dopant types and contents(0,2,5,and 8 wt.%)on the wettability and interfacial reaction between the alloy and shell were investigated by a sessile-drop experiment.The results show that increasing the Al_(2)O_(3) doping contents(0−8 wt.%)reduces the porosity(21.74%−10.08%)and roughness(3.22−1.34μm)of the shell surface.The increase in Cr_(2)O_(3) dopant content(2−8 wt.%)further exacerbates the interfacial reaction,leading to an increase in the thickness of the reaction layer(2.6−3.1μm)and a decrease in the wetting angle(93.9°−91.0°).The addition of Al_(2)O_(3) and TiO_(2) dopants leads to the formation of Al_(2)TiO_(5) composite oxides in the reaction products,which effectively inhibits the interfacial reaction.The increase in TiO_(2) dopant contents(0−8 wt.%)further promotes the formation of Al_(2)TiO_(5),which decreases the thickness of the interfacial reaction layer(3.9−1.2μm)and increases the wetting angle(95.0°−103.8°).The introduced dopants enhance the packing density of the shell surface,while simultaneously suppress the diffusion of active metal elements from the alloy matrix to the interface.展开更多
Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electro...Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electrocatalytic oxidations of saturated alcohols(C_(1)-C_(6))to selectively form formate using Ni Co hydroxide(Ni Co-OH)derived Ni Co_(2)O_(4)solid-acid electrocatalysts with balanced Lewis acid(LASs)and Brønsted acid sites(BASs).Thermal treatment transforms BASs-rich(89.6%)Ni Co-OH into Ni Co_(2)O_(4)with nearly equal distribution of LASs(53.1%)and BASs(46.9%)which synergistically promote adsorption and activation of OH-and alcohol molecules for enhanced oxidation activity.In contrast,BASs-enriched Ni Co-OH facilitates formation of higher valence metal sites,beneficial for water oxidation.The combined experimental studies and theoretical calculation imply the oxidation ability of C1-C6alcohols increases as increased number of hydroxyl groups and decreased HOMO-LUMO gaps:methanol(C_(1))<ethylene glycol(C_(2))<glycerol(C3)<meso-erythritol(C4)<xylitol(C5)<sorbitol(C6),while the formate selectivity shows the opposite trend from 100 to 80%.This study unveils synergistic roles of LASs and BASs,as well as hydroxyl group effect in electro-upgrading of alcohols using solid-acid electrocatalysts.展开更多
Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in hu...Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in humans remain unclear,including cell viability,distribution,migration,and fate.Conventional cell tracing methods cannot be used in the clinic.The use of superparamagnetic iron oxide nanoparticles as contrast agents allows for the observation of transplanted cells using magnetic resonance imaging.In 2016,the National Medical Products Administration of China approved a new superparamagnetic iron oxide nanoparticle,Ruicun,for use as a contrast agent in clinical trials.In the present study,an acute hemi-transection spinal cord injury model was established in beagle dogs.The injury was then treated by transplantation of Ruicun-labeled mesenchymal stromal cells.The results indicated that Ruicunlabeled mesenchymal stromal cells repaired damaged spinal cord fibers and partially restored neurological function in animals with acute spinal cord injury.T2*-weighted imaging revealed low signal areas on both sides of the injured spinal cord.The results of quantitative susceptibility mapping with ultrashort echo time sequences indicated that Ruicun-labeled mesenchymal stromal cells persisted stably within the injured spinal cord for over 4 weeks.These findings suggest that magnetic resonance imaging has the potential to effectively track the migration of Ruicun-labeled mesenchymal stromal cells and assess their ability to repair spinal cord injury.展开更多
Infrared-transparent conductors have attracted considerable attention due to their potential applications in electromagnetic shielding,infrared sensors,and photovoltaic devices.However,most known materials face the cr...Infrared-transparent conductors have attracted considerable attention due to their potential applications in electromagnetic shielding,infrared sensors,and photovoltaic devices.However,most known materials face the critical challenge of balancing high infrared transmittance with high electrical conductivity across the broad infrared spectral band(2.5-25μm).While ultra-thin indium tin oxide(ITO)films have been demonstrated to exhibit superior infrared transmittance,their inherent low electrical conductivity necessitates additional enhancement strategies.This study systematically investigates the effects of oxygen vacancy concentration regulation and ultra-thin copper capping layer integration on the infrared optoelectronic properties of 20 nm-thick ITO films.A fundamental trade-off is revealed in ITO films that increased oxygen vacancy content enhances the electrical conductivity while compromising the infrared transmittance.Meanwhile,following the introduction of a Cu capping layer,the Cu/ITO system exhibits opposing dependencies of infrared transmittance and electrical conductivity on the capping layer thickness,with an optimum thickness of~3 nm.Finally,by constructing a Cu(3 nm)/ITO(20 nm)heterostructure with varying oxygen vacancy content,we demonstrate the combined effect of the ultra-thin Cu capping layer and moderate oxygen vacancy content on optimizing the carrier transport network.This configuration simultaneously minimizes surface/interfacial reflection and absorption losses,achieving high infrared transmittance(0.861)and a low sheet resistance of 400 W/sq.Our findings highlight the critical role of the combined effect of metal/oxide heterostructure design and defect engineering in optimizing infrared-transparent conductive properties.展开更多
The reduction of global carbon emissions and the achievement of carbon neutrality have become the focus of addressing climate change and global warming.Electrochemical CO_(2) reduction(CO_(2)RR),as a technology that c...The reduction of global carbon emissions and the achievement of carbon neutrality have become the focus of addressing climate change and global warming.Electrochemical CO_(2) reduction(CO_(2)RR),as a technology that can efficiently convert CO_(2) into value-added products,is receiving widespread attention.This article reviews the current research status of Cu/metal oxide heterostructures in the field of electrochemical reduction of CO_(2).The review first introduces the importance of electrochemical reduction of CO_(2) and the application potential of Cu/metal oxide heterostructures in this field.Subsequently,a comprehensive discussion is presented on the exploration of various Cu/metal oxide heterostructures and their corresponding structure-performance relationship,with particular emphasis on the catalysts'activity,selectivity,stability and the nature of active sites.Lastly,the review provides an overview of the current research challenges and future development trends in this field.展开更多
CuO/γ-Al2O3 catalysts were prepared by impregnation with different CuO loadings. The dispersion of CuO supported on γ-Al2O3 support was studied using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, ...CuO/γ-Al2O3 catalysts were prepared by impregnation with different CuO loadings. The dispersion of CuO supported on γ-Al2O3 support was studied using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and temperature programmed reduction （TPR）. The dispersion threshold of CuO in γ-Al2O3 determined by X-ray quantitative analysis was 0.275 g/g, i.e., 0.275CuAl. Highly dispersed CuO or crystalline CuO would appear on the γ-Al2O3 support when CuO loading was below or more than its dispersion threshold. TPR experiments show that reduction peak temperature ranges of 0.1CuAl and pure CuO are 420-690 °C and 290-380 °C, respectively. 0.1CuAl is not easily reduced due to interaction between CuO and γ-Al2O3. 0.5CuAl shows a two-step reduction range during 210-300 °C and 410-730 °C, which confirms the existence of highly dispersed CuO and crystalline CuO. The sulfation experiments show the optimal CuO loading amount is far below its dispersion threshold, and copper oxide supported on γ-Al2O3 is in the form of submonolayer.展开更多
A series of copper manganese oxides were prepared using a selective etching technique with various amounts of ammonia added during the co-precipitation process. The effect of the ammonia etching on the structure and c...A series of copper manganese oxides were prepared using a selective etching technique with various amounts of ammonia added during the co-precipitation process. The effect of the ammonia etching on the structure and catalytic properties of the copper manganese oxides was investigated using elemental analysis, nitrogen physisorption, X-ray powder diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, H2 temperature-programmed reduc- tion, and Oz temperature-programmed desorption combined with catalytic oxidation of CO. It was found that ammonia can selectively remove copper species from the copper manganese oxides, which correspondingly generates more defects in these oxides. An oxygen spillover from the man- ganese to the copper species was observed by H2 temperature-programmed desorption, indicating that ammonia etching enhanced the mobility of lattice oxygen species in these oxides. The Oz tem- perature-programmed desorption measurements further revealed that ammonia etching improved the ability of these oxides to release lattice oxygen. The improvement in redox properties of the copper manganese oxides following ammonia etching was associated with enhanced catalytic performance for CO oxidation.展开更多
The catalytic epoxidation of olefin was investigated on two copper complex-modified molybdenum oxides with a 3D supramolecular structure, [Cu（bipy）]4[Mo15O47].2H2O （1） and [Cu1（bix）][（Cu1bix） （δ-MoVl8O26）0....The catalytic epoxidation of olefin was investigated on two copper complex-modified molybdenum oxides with a 3D supramolecular structure, [Cu（bipy）]4[Mo15O47].2H2O （1） and [Cu1（bix）][（Cu1bix） （δ-MoVl8O26）0.5] （2） （bipy = 4,4＇-bipyridine, bix = 1,4-bis（imidazole-1-ylmethyl）benzene）. Both compounds were catalytically active and stable for the epoxidation of cyclooctene, 1-octene, and styrene with tert-butyl hydroperoxide （t-BuOOH） as oxidant. The excellent catalytic performance was attributed to the presence of stable coordination bonds between the molybdenum oxide and copper complex, which resulted in the formation of easily accessible Mo species with high electropositivity. In addition, the copper complex also acted as an active site for the activation of t-BuOOH, thus im- proving these copper complex-modified polyoxometalates.展开更多
The influence of Ce doping and the precipitation method on structural properties and the catalytic activity of copper manganese oxides for CO oxidation at ambient temperature have been investigated. The catalysts were...The influence of Ce doping and the precipitation method on structural properties and the catalytic activity of copper manganese oxides for CO oxidation at ambient temperature have been investigated. The catalysts were characterized by means of the powder X-ray diffraction and N2 adsorption-desorption, the inductively coupled plasma atomic emission spectrometry, the temperature programmed reduction, diffuse reflectance UV-Vis spectra, and the X-ray photoelectron spectroscopy. It was found that after doping little amount of Ce in copper manganese oxide, CeO2 phase was highly dispersed and could prevent sintering and aggregating of the catalyst, the size of the catalytic material was decreased, the reducibility was enhanced, the specific surface area was increased and the formation of the active sites for the oxidation of CO was improved significantly. Therefore, the activity of the rare earth promoted catalyst was enhanced remarkably.展开更多
A series of meso‐microporous copper‐supporting chabazite molecular sieve（CuSAPO‐34） catalysts with excellent performance in low‐temperature ammonia selective catalytic reduction（NH3‐SCR）have been synthesized ...A series of meso‐microporous copper‐supporting chabazite molecular sieve（CuSAPO‐34） catalysts with excellent performance in low‐temperature ammonia selective catalytic reduction（NH3‐SCR）have been synthesized via a one‐pot hydrothermal crystallization method. The physicochemical properties of the catalysts were characterized by scanning electron microscopy, transmission electron microscopy, N2 adsorption‐desorption measurements, X‐ray diffraction, 27 Al magic angle spinning nuclear magnetic resonance, diffuse reflectance ultraviolet‐visible spectroscopy, inductively coupled plasma‐atomic emission spectroscopy, X‐ray photoelectron spectroscopy, temperature‐programmed reduction measurements, and electron paramagnetic resonance analysis. The formation of micro‐mesopores in the Cu‐SAPO‐34 catalysts decreases diffusion resistance and greatly improves the accessibility of reactants to catalytic active sites. The main active sites for NH3‐SCR reaction are the isolated Cu^2＋ species displaced into the ellipsoidal cavity of the Cu‐SAPO‐34 catalysts.展开更多
The effect of sodium butyl xanthate (NaBX) and dodecylamine (DDA) as combined collector on the sulphidizing flotation of copper oxide was investigated by flotation test, fluorescent pyrene probe, zeta potential, and i...The effect of sodium butyl xanthate (NaBX) and dodecylamine (DDA) as combined collector on the sulphidizing flotation of copper oxide was investigated by flotation test, fluorescent pyrene probe, zeta potential, and infrared spectroscopy analyses. The micro-flotation results show that combined use of NaBX+DDA yields better effect than using NaBX at pH 7-11 only, and the optimal molar ratio of NaBX to DDA is 2: 1. The actual ores flotation shows that when the dosage of NaBX+DDA is (100+54) g/t, the copper concentrate grade and recovery are 15.93% and 76.73%, respectively. The fluorescent pyrene probe test demonstrates that the NaBX+DDA can reduce the micelle concentration in the pulp. The zeta potential and the infrared spectroscopy analyses indicate that chemical adsorption, hydrogen-bonding and electrostatic interaction can help to adsorb NaBX+DDA on the surface of malachite. Meantime, copper xanthate and copper-amine complexes may be generated during the adsorption process.展开更多
基金Project(21471162)supported by the National Natural Science Foundation of ChinaProject(2014LY36)supported by the Science and Technology Project of Longyan CityChina
文摘A promising Co3O4/Cu O composite electrode material was successfully synthesized through a facile hydrothermal and calcination process. Effects of the surfactants hexadecyltrimethyl ammonium bromide（CTAB） and polyvinylpyrrolidone（PVP） on the morphology and electrochemical performance of the composite were investigated. Powder X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and nitrogen adsorption-desorption experiment were employed to characterize the microstructures and morphologies of the composite. Meanwhile, the electrochemical performances of the samples were studied using cyclic voltammetry（CV）, galvanostatic charge-discharge test and electrochemical impedance spectroscopy（EIS）. The results show that the porous Co3O4/Cu O-CTAB nanoplates own the best performance and exhibits a high specific capacitance of 398 F/g at 1 A/g with almost 100% capacitance retention over 2000 cycles, and it retains 90% of capacitance at 10 A/g.
文摘Black nickel coatings have emerged as a research hotspot in materials science due to their excellent performance and broad application prospects.In this study,nickel-based black coatings were fabricated on low-carbon steel substrates via photo-assisted electrodeposition.A systematic investigation was conducted on the effects of cerium ion concentration and nano-ceria(CeO_(2))particle content in the electrolyte on the coating properties,along with an analysis of the temporal evolution of coating’s corrosion resistance.When the cerium ion concentration in the electrolyte was 0.05 mol/L,the coating exhibited a uniform black appearance with a light absorption rate of 95%,an emissivity of 0.87,maximum impedance,and the lowest corrosion tendency,demonstrating optimal comprehensive performance.The coating prepared with a nano-ceria concentration of 6 g/L in the electrolyte exhibited an emissivity of 0.9,achieved a 5B adhesion grade(ASTM D3359-09),and demonstrated a one-order-of-magnitude reduction in corrosion current density compared to coatings fabricated without nano-ceria in the electrolyte.With prolonged storage time,the coating's impedance slightly increased,leading to improved corrosion resistance.
基金financially supported by the National Natural Science Foundation of China(Grant No.12172093)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2021A1515012607)。
文摘High-entropy oxides(HEOs)have emerged as a promising class of memristive materials,characterized by entropy-stabilized crystal structures,multivalent cation coordination,and tunable defect landscapes.These intrinsic features enable forming-free resistive switching,multilevel conductance modulation,and synaptic plasticity,making HEOs attractive for neuromorphic computing.This review outlines recent progress in HEO-based memristors across materials engineering,switching mechanisms,and synaptic emulation.Particular attention is given to vacancy migration,phase transitions,and valence-state dynamics—mechanisms that underlie the switching behaviors observed in both amorphous and crystalline systems.Their relevance to neuromorphic functions such as short-term plasticity and spike-timing-dependent learning is also examined.While encouraging results have been achieved at the device level,challenges remain in conductance precision,variability control,and scalable integration.Addressing these demands a concerted effort across materials design,interface optimization,and task-aware modeling.With such integration,HEO memristors offer a compelling pathway toward energy-efficient and adaptable brain-inspired electronics.
基金supported by Korea Evaluation Institute of Industrial Technology(KEIT)grant funded by the Korea Government(MOTIE)(RS-2022-00154720,Technology Innovation Program Development of next-generation power semiconductor based on Si-on-SiC structure)the National Research Foundation of Korea(NRF)by the Korea government(RS-2023-NR076826)Global-Learning&Academic Research Institution for Master's·PhD students,and Postdocs(LAMP)Program of the National Research Foundation of Korea(NRF)by the Ministry of Education(No.RS-2024-00443714).
文摘Improving device efficiency is fundamental for advancing energy harvesting technology,particularly in systems designed to convert light energy into electrical output.In our previous studies,we developed a basic structure light pressure electric generator(Basic-LPEG),which utilized a layered configuration of Ag/Pb(Zr,Ti)O_(3)(PZT)/Pt/GaAs to generate electricity based on light-induced pressure on the PZT.In this study,we sought to enhance the performance of this Basic-LPEG by introducing Ag nanoparticles/graphene oxide(AgNPs/GO)composite units(NP-LPEG),creating upgraded harvesting device.Specifically,by depositing the AgNPs/GO units twice onto the Basic-LPEG,we observed an increase in output voltage and current from 241 mV and 3.1μA to 310 mV and 9.3μA,respectively,under a solar simulator.The increase in electrical output directly correlated with the intensity of the light pressure impacting the PZT,as well as matched the Raman measurements,finite-difference time-domain simulations,and COMSOL Multiphysics Simulation.Experimental data revealed that the enhancement in electrical output was proportional to the number of hot spots generated between Ag nanoparticles,where the electric field experienced substantial amplification.These results underline the effectiveness of AgNPs/GO units in boosting the light-induced electric generation capacity,thereby providing a promising pathway for high-efficiency energy harvesting devices.
基金supported by the National Natural ScienceFoundation of China(Grant No.52203332)。
文摘The thermal decomposition characteristic of ammonium perchlorate(AP)represents a critical factor in determining the performance of solid propellants,which has aroused significant interest on the structure and performance improvement of kinds of catalysts.In this study,bimetallic metal-organic frameworks(MOFs),such as CuCo-BTC(BTC=1,3,5-Benzenetricarboxylic acid,H_(3)BTC),CuNi-BTC,and CoNi-BTC,were synthesized by solvothermal(ST)and spray-drying(SD)methods,and then calcined at 400℃for 2 h to form metal oxides.The catalysts as well as their catalytic effects for AP decomposition were characterized by FTIR,XRD,SEM,XPS,TG,DSC,TG-IR,EIS,CV,and LSV.It was found that the rapid coordination of metal ions with ligands during spray drying may lead to catalytic structural defects,promoting the exposure of reactive active sites and increasing the catalytic active region.The results showed that the addition of 2 wt%binary transition metal oxides(BTMOs)as catalysts significantly reduced the high-temperature decomposition(HTD)temperature of AP and enhanced its heat release.Of particular significance is the observation that SD-CoNiO_(x),prepared by spray-drying,reduced the decomposition temperature of AP from 413.26℃(pure AP)to 306℃and enhanced the heat release from 256.79 J/g(pure AP)to 1496.82 J/g,while concomitantly reducing the activation energy by 42%.By analysing the gaseous products during the decomposition of AP+SD-CoNiO_(x)and AP+ST-CoNiO_(x),it was found that SD-CoNiO_(x)could significantly increase the content of high-valent nitrogen oxides during the AP decomposition reaction,which indicates that the BTMOs prepared by spray-drying in the reaction system are more conducive to accelerating the electron transfer in the thermal decomposition process of AP,and can provide a high concentration of reactive oxygen species that oxidize AP to high-valent nitrogen oxide-containing compounds.The present study shows that the structure selectivity of the spray-drying technique influences surfactant molecular arrangement on catalyst surfaces,resulting in their ability to promote higher electron transfer during the catalytic process.Therefore,BTMOs prepared by spray drying method have higher potential for application.
基金financially supported by the National Natural Science Foundation of China(No.22309067)the Open Project Program of the State Key Laboratory of Materials-Oriented Chemical Engineering,China(No.KL21-05)the Marine Equipment and Technology Institute,Jiangsu University of Science and Technology,China(No.XTCX202404)。
文摘This study focused on improving the cathode performance of Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.15)O_(3-δ)(BSCN)-based perovskite materials through molybdenum(Mo)doping.Pure BSCN and Mo-modified-BSCN—Ea_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.1)Mo_(0.05)O_(3-δ)(B S CNM_(0.05)),Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.05)Mo_(0.1)O_(3-δ)(BSCNM_(0.1)),and Ba_(0.6)Sr_(0.4)Co_(0.85)Mo_(0.15)O_(3-δ)(BSCM)—with Mo doping contents of 5mol%,10mol%,and15mol%,respectively,were successfully prepared using the sol-gel method.The effects of Mo doping on the crystal structure,conductivity,thermal expansion coefficient,oxygen reduction reaction(ORR)activity,and electrochemical performance were systematically evaluated using X-ray diffraction analysis,thermally induced characterization,electrochemical impedance spectroscopy,and single-cell performance tests.The results revealed that Mo doping could improve the conductivity of the materials,suppress their thermal expansion effects,and significantly improve the electrochemical performance.Surface chemical state analysis using X-ray photoelectron spectroscopy revealed that 5mol%Mo doping could facilitate a high adsorbed oxygen concentration leading to enhanced ORR activity in the materials.Density functional theory calculations confirmed that Mo doping promoted the ORR activity in the materials.At an operating temperature of 600℃,the BSCNM_(0.05)cathode material exhibited significantly enhanced electrochemical impedance characteristics,with a reduced area specific resistance of 0.048Ω·cm~2,which was lower than that of the undoped BSCN matrix material by 32.39%.At the same operating temperature,an anode-supported single cell using a BSCNM_(0.05)cathode achieved a peak power density of 1477 mW·cm^(-2),which was 30.71%,56.30%,and 171.50%higher than those of BSCN,BSCNM_(0.1),and B SCM,respectively.The improved ORR activity and electrochemical performance of BSCNM_(0.05)indicate that it can be used as a cathode material in low-temperature solid oxide fuel cells.
基金financial support of the National Natural Science Foundation of China(No.52371103)the Fundamental Research Funds for the Central Universities,China(No.2242023K40028)+1 种基金the Open Research Fund of Jiangsu Key Laboratory for Advanced Metallic Materials,China(No.AMM2023B01).financial support of the Research Fund of Shihezi Key Laboratory of AluminumBased Advanced Materials,China(No.2023PT02)financial support of Guangdong Province Science and Technology Major Project,China(No.2021B0301030005)。
文摘Oxide dispersion strengthened(ODS)alloys are extensively used owing to high thermostability and creep strength contributed from uniformly dispersed fine oxides particles.However,the existence of these strengthening particles also deteriorates the processability and it is of great importance to establish accurate processing maps to guide the thermomechanical processes to enhance the formability.In this study,we performed particle swarm optimization-based back propagation artificial neural network model to predict the high temperature flow behavior of 0.25wt%Al2O3 particle-reinforced Cu alloys,and compared the accuracy with that of derived by Arrhenius-type constitutive model and back propagation artificial neural network model.To train these models,we obtained the raw data by fabricating ODS Cu alloys using the internal oxidation and reduction method,and conducting systematic hot compression tests between 400 and800℃with strain rates of 10^(-2)-10 S^(-1).At last,processing maps for ODS Cu alloys were proposed by combining processing parameters,mechanical behavior,microstructure characterization,and the modeling results achieved a coefficient of determination higher than>99%.
基金funding support from General Research Fund[Project No.14300525]from the Research Grants Council(RGC)of Hong Kong SAR,Chinafunding support from Natural Science Foundation of China(NSFC)Young Scientists Fund(Project No.22305203)+2 种基金NSFC Projects Nos.22309123,22422303,22303011,22033002,92261112 and U21A20328support from the Hong Kong Branch of National Precious Metals Material Engineering Research Center(NPMM)at City University of Hong Kongsupport from Young Collaborative Research Grant[Project No.C1003-23Y]support from RGC of Hong Kong SAR,China.
文摘Electrocatalytic nitric oxide(NO)reduction reaction(NORR)is a promising and sustainable process that can simultaneously realize green ammonia(NH3)synthesis and hazardous NO removal.However,current NORR performances are far from practical needs due to the lack of efficient electrocatalysts.Engineering the lattice of metal-based nanomaterials via phase control has emerged as an effective strategy to modulate their intrinsic electrocatalytic properties.Herein,we realize boron(B)-insertion-induced phase regulation of rhodium(Rh)nanocrystals to obtain amorphous Rh_(4)B nanoparticles(NPs)and hexagonal close-packed(hcp)RhB NPs through a facile wet-chemical method.A high Faradaic efficiency(92.1±1.2%)and NH_(3) yield rate(629.5±11.0μmol h^(−1) cm^(−2))are achieved over hcp RhB NPs,far superior to those of most reported NORR nanocatalysts.In situ spectro-electrochemical analysis and density functional theory simulations reveal that the excellent electrocatalytic performances of hcp RhB NPs are attributed to the upshift of d-band center,enhanced NO adsorption/activation profile,and greatly reduced energy barrier of the rate-determining step.A demonstrative Zn-NO battery is assembled using hcp RhB NPs as the cathode and delivers a peak power density of 4.33 mW cm−2,realizing simultaneous NO removal,NH3 synthesis,and electricity output.
基金supported by the National Natural Science Foundation of China(No.22101289)Hundred Talents Programs in Chinese Academy of Science,and the Ningbo S&T Innovation 2025 Major Special Program(No.2022Z205).
文摘Electrochemical CO_(2) reduction reaction(CO_(2)RR),driven by renewable energy,offers a promising solution to mitigate increasing CO_(2) emissions and establish a carbon-neutral cycle.Copper is a highly selective and active catalyst for CO_(2)RR but suffers from structural reconstruction challenges.Hybrid organic/inorganic materials address these issues by offering customizable compositions and interfaces.Recently,Buonsanti’s team developed hybrid Cu@AlOx nanocrystals with tunable alumina shells via a colloidal atomic layer deposition approach,achieving stable and selective methane production during CO_(2)RR.Mechanistic studies reveal that the alumina shell stabilizes oxidized copper species through Cu^(2+)-O-Al motifs coordinated with AlO_(4) Lewis acid sites,reducing copper dissolution and structural reconstruction.This study provides key insights into the mechanism underlying stabilization,highlighting the critical role of Lewis acidity in preserving the structural integrity of the catalyst.This highlight review aims to inspire the development of other high-performance and stable catalysts through colloidal atomic layer deposition strategies.
基金supported by the National Natural Science Foundation of China (No. 52374292)China Baowu Low Carbon Metallurgy Innovation Foundation, China (No. BWLCF202309)the Natural Science Foundation of Changsha City, China (No. KQ2208271)。
文摘Some active metal oxides(Al_(2)O_(3),TiO_(2),and Cr_(2)O_(3))were selected as dopants to the Al_(2)O_(3)-based ceramic shells for investment casting of K417G superalloy.The effects of dopant types and contents(0,2,5,and 8 wt.%)on the wettability and interfacial reaction between the alloy and shell were investigated by a sessile-drop experiment.The results show that increasing the Al_(2)O_(3) doping contents(0−8 wt.%)reduces the porosity(21.74%−10.08%)and roughness(3.22−1.34μm)of the shell surface.The increase in Cr_(2)O_(3) dopant content(2−8 wt.%)further exacerbates the interfacial reaction,leading to an increase in the thickness of the reaction layer(2.6−3.1μm)and a decrease in the wetting angle(93.9°−91.0°).The addition of Al_(2)O_(3) and TiO_(2) dopants leads to the formation of Al_(2)TiO_(5) composite oxides in the reaction products,which effectively inhibits the interfacial reaction.The increase in TiO_(2) dopant contents(0−8 wt.%)further promotes the formation of Al_(2)TiO_(5),which decreases the thickness of the interfacial reaction layer(3.9−1.2μm)and increases the wetting angle(95.0°−103.8°).The introduced dopants enhance the packing density of the shell surface,while simultaneously suppress the diffusion of active metal elements from the alloy matrix to the interface.
基金the financial support from the National Natural Science Foundation of China(52172110,52472231,52311530113)Shanghai"Science and Technology Innovation Action Plan"intergovernmental international science and technology cooperation project(23520710600)+1 种基金Science and Technology Commission of Shanghai Municipality(22DZ1205600)the Central Guidance on Science and Technology Development Fund of Zhejiang Province(2024ZY01011)。
文摘Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electrocatalytic oxidations of saturated alcohols(C_(1)-C_(6))to selectively form formate using Ni Co hydroxide(Ni Co-OH)derived Ni Co_(2)O_(4)solid-acid electrocatalysts with balanced Lewis acid(LASs)and Brønsted acid sites(BASs).Thermal treatment transforms BASs-rich(89.6%)Ni Co-OH into Ni Co_(2)O_(4)with nearly equal distribution of LASs(53.1%)and BASs(46.9%)which synergistically promote adsorption and activation of OH-and alcohol molecules for enhanced oxidation activity.In contrast,BASs-enriched Ni Co-OH facilitates formation of higher valence metal sites,beneficial for water oxidation.The combined experimental studies and theoretical calculation imply the oxidation ability of C1-C6alcohols increases as increased number of hydroxyl groups and decreased HOMO-LUMO gaps:methanol(C_(1))<ethylene glycol(C_(2))<glycerol(C3)<meso-erythritol(C4)<xylitol(C5)<sorbitol(C6),while the formate selectivity shows the opposite trend from 100 to 80%.This study unveils synergistic roles of LASs and BASs,as well as hydroxyl group effect in electro-upgrading of alcohols using solid-acid electrocatalysts.
基金supported by the National Key R&D Program of China,Nos.2017YFA0104302(to NG and XM)and 2017YFA0104304(to BW and ZZ)
文摘Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in humans remain unclear,including cell viability,distribution,migration,and fate.Conventional cell tracing methods cannot be used in the clinic.The use of superparamagnetic iron oxide nanoparticles as contrast agents allows for the observation of transplanted cells using magnetic resonance imaging.In 2016,the National Medical Products Administration of China approved a new superparamagnetic iron oxide nanoparticle,Ruicun,for use as a contrast agent in clinical trials.In the present study,an acute hemi-transection spinal cord injury model was established in beagle dogs.The injury was then treated by transplantation of Ruicun-labeled mesenchymal stromal cells.The results indicated that Ruicunlabeled mesenchymal stromal cells repaired damaged spinal cord fibers and partially restored neurological function in animals with acute spinal cord injury.T2*-weighted imaging revealed low signal areas on both sides of the injured spinal cord.The results of quantitative susceptibility mapping with ultrashort echo time sequences indicated that Ruicun-labeled mesenchymal stromal cells persisted stably within the injured spinal cord for over 4 weeks.These findings suggest that magnetic resonance imaging has the potential to effectively track the migration of Ruicun-labeled mesenchymal stromal cells and assess their ability to repair spinal cord injury.
基金supported by the National Key R&D Program of China(Grant No.2022YFB3806300).
文摘Infrared-transparent conductors have attracted considerable attention due to their potential applications in electromagnetic shielding,infrared sensors,and photovoltaic devices.However,most known materials face the critical challenge of balancing high infrared transmittance with high electrical conductivity across the broad infrared spectral band(2.5-25μm).While ultra-thin indium tin oxide(ITO)films have been demonstrated to exhibit superior infrared transmittance,their inherent low electrical conductivity necessitates additional enhancement strategies.This study systematically investigates the effects of oxygen vacancy concentration regulation and ultra-thin copper capping layer integration on the infrared optoelectronic properties of 20 nm-thick ITO films.A fundamental trade-off is revealed in ITO films that increased oxygen vacancy content enhances the electrical conductivity while compromising the infrared transmittance.Meanwhile,following the introduction of a Cu capping layer,the Cu/ITO system exhibits opposing dependencies of infrared transmittance and electrical conductivity on the capping layer thickness,with an optimum thickness of~3 nm.Finally,by constructing a Cu(3 nm)/ITO(20 nm)heterostructure with varying oxygen vacancy content,we demonstrate the combined effect of the ultra-thin Cu capping layer and moderate oxygen vacancy content on optimizing the carrier transport network.This configuration simultaneously minimizes surface/interfacial reflection and absorption losses,achieving high infrared transmittance(0.861)and a low sheet resistance of 400 W/sq.Our findings highlight the critical role of the combined effect of metal/oxide heterostructure design and defect engineering in optimizing infrared-transparent conductive properties.
基金supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX23_0120)the National Natural Science Foundation of China(Nos.22275088 and 52101260)+3 种基金the Project of Shuangchuang Scholar of Jiangsu Province(No.JSSCBS20210212)the Fundamental Research Funds for the Central Universities(No.30921011203)the Start-Up Grant(No.AE89991/340)from Nanjing University of Science and Technology,the Foundation of Jiangsu Educational Committee(No.22KJB310008)the Senior Talent Program of Jiangsu University(No.20JDG073).
文摘The reduction of global carbon emissions and the achievement of carbon neutrality have become the focus of addressing climate change and global warming.Electrochemical CO_(2) reduction(CO_(2)RR),as a technology that can efficiently convert CO_(2) into value-added products,is receiving widespread attention.This article reviews the current research status of Cu/metal oxide heterostructures in the field of electrochemical reduction of CO_(2).The review first introduces the importance of electrochemical reduction of CO_(2) and the application potential of Cu/metal oxide heterostructures in this field.Subsequently,a comprehensive discussion is presented on the exploration of various Cu/metal oxide heterostructures and their corresponding structure-performance relationship,with particular emphasis on the catalysts'activity,selectivity,stability and the nature of active sites.Lastly,the review provides an overview of the current research challenges and future development trends in this field.
基金Project (Jinchuan 201114) supported by the Pre-Research Foundation of Jinchuan Group Ltd., ChinaProject (2011148) supported by the Analysis and Testing Foundation of Kunming University of Science and Technology, China
文摘CuO/γ-Al2O3 catalysts were prepared by impregnation with different CuO loadings. The dispersion of CuO supported on γ-Al2O3 support was studied using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and temperature programmed reduction （TPR）. The dispersion threshold of CuO in γ-Al2O3 determined by X-ray quantitative analysis was 0.275 g/g, i.e., 0.275CuAl. Highly dispersed CuO or crystalline CuO would appear on the γ-Al2O3 support when CuO loading was below or more than its dispersion threshold. TPR experiments show that reduction peak temperature ranges of 0.1CuAl and pure CuO are 420-690 °C and 290-380 °C, respectively. 0.1CuAl is not easily reduced due to interaction between CuO and γ-Al2O3. 0.5CuAl shows a two-step reduction range during 210-300 °C and 410-730 °C, which confirms the existence of highly dispersed CuO and crystalline CuO. The sulfation experiments show the optimal CuO loading amount is far below its dispersion threshold, and copper oxide supported on γ-Al2O3 is in the form of submonolayer.
基金supported by the National Basic Research Program of China (973 Program,2013CB934104)the China Postdoctoral Science Foundation(2014M560202)~~
文摘A series of copper manganese oxides were prepared using a selective etching technique with various amounts of ammonia added during the co-precipitation process. The effect of the ammonia etching on the structure and catalytic properties of the copper manganese oxides was investigated using elemental analysis, nitrogen physisorption, X-ray powder diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, H2 temperature-programmed reduc- tion, and Oz temperature-programmed desorption combined with catalytic oxidation of CO. It was found that ammonia can selectively remove copper species from the copper manganese oxides, which correspondingly generates more defects in these oxides. An oxygen spillover from the man- ganese to the copper species was observed by H2 temperature-programmed desorption, indicating that ammonia etching enhanced the mobility of lattice oxygen species in these oxides. The Oz tem- perature-programmed desorption measurements further revealed that ammonia etching improved the ability of these oxides to release lattice oxygen. The improvement in redox properties of the copper manganese oxides following ammonia etching was associated with enhanced catalytic performance for CO oxidation.
基金supported by the National Natural Science Foundation of China(21173100 and 21320102001)~~
文摘The catalytic epoxidation of olefin was investigated on two copper complex-modified molybdenum oxides with a 3D supramolecular structure, [Cu（bipy）]4[Mo15O47].2H2O （1） and [Cu1（bix）][（Cu1bix） （δ-MoVl8O26）0.5] （2） （bipy = 4,4＇-bipyridine, bix = 1,4-bis（imidazole-1-ylmethyl）benzene）. Both compounds were catalytically active and stable for the epoxidation of cyclooctene, 1-octene, and styrene with tert-butyl hydroperoxide （t-BuOOH） as oxidant. The excellent catalytic performance was attributed to the presence of stable coordination bonds between the molybdenum oxide and copper complex, which resulted in the formation of easily accessible Mo species with high electropositivity. In addition, the copper complex also acted as an active site for the activation of t-BuOOH, thus im- proving these copper complex-modified polyoxometalates.
文摘The influence of Ce doping and the precipitation method on structural properties and the catalytic activity of copper manganese oxides for CO oxidation at ambient temperature have been investigated. The catalysts were characterized by means of the powder X-ray diffraction and N2 adsorption-desorption, the inductively coupled plasma atomic emission spectrometry, the temperature programmed reduction, diffuse reflectance UV-Vis spectra, and the X-ray photoelectron spectroscopy. It was found that after doping little amount of Ce in copper manganese oxide, CeO2 phase was highly dispersed and could prevent sintering and aggregating of the catalyst, the size of the catalytic material was decreased, the reducibility was enhanced, the specific surface area was increased and the formation of the active sites for the oxidation of CO was improved significantly. Therefore, the activity of the rare earth promoted catalyst was enhanced remarkably.
基金supported by the National Natural Science Foundation of China(2137626121173270)+4 种基金the National High Technology Research and Development Program of China(863 Program2015AA034603)the Beijing Natural Science Foundation(2142027)the China University of Petroleum Fund(201300071100072462015QZDX04)~~
文摘A series of meso‐microporous copper‐supporting chabazite molecular sieve（CuSAPO‐34） catalysts with excellent performance in low‐temperature ammonia selective catalytic reduction（NH3‐SCR）have been synthesized via a one‐pot hydrothermal crystallization method. The physicochemical properties of the catalysts were characterized by scanning electron microscopy, transmission electron microscopy, N2 adsorption‐desorption measurements, X‐ray diffraction, 27 Al magic angle spinning nuclear magnetic resonance, diffuse reflectance ultraviolet‐visible spectroscopy, inductively coupled plasma‐atomic emission spectroscopy, X‐ray photoelectron spectroscopy, temperature‐programmed reduction measurements, and electron paramagnetic resonance analysis. The formation of micro‐mesopores in the Cu‐SAPO‐34 catalysts decreases diffusion resistance and greatly improves the accessibility of reactants to catalytic active sites. The main active sites for NH3‐SCR reaction are the isolated Cu^2＋ species displaced into the ellipsoidal cavity of the Cu‐SAPO‐34 catalysts.
基金Projects(51504053,51374079)supported by the National Natural Science Foundation of China
文摘The effect of sodium butyl xanthate (NaBX) and dodecylamine (DDA) as combined collector on the sulphidizing flotation of copper oxide was investigated by flotation test, fluorescent pyrene probe, zeta potential, and infrared spectroscopy analyses. The micro-flotation results show that combined use of NaBX+DDA yields better effect than using NaBX at pH 7-11 only, and the optimal molar ratio of NaBX to DDA is 2: 1. The actual ores flotation shows that when the dosage of NaBX+DDA is (100+54) g/t, the copper concentrate grade and recovery are 15.93% and 76.73%, respectively. The fluorescent pyrene probe test demonstrates that the NaBX+DDA can reduce the micelle concentration in the pulp. The zeta potential and the infrared spectroscopy analyses indicate that chemical adsorption, hydrogen-bonding and electrostatic interaction can help to adsorb NaBX+DDA on the surface of malachite. Meantime, copper xanthate and copper-amine complexes may be generated during the adsorption process.
