Liquid phase oxidation of toluene is an environmental benign route for the production of benzoic acid.In a φ48mm bubble column reactor,the commercial process of toluene liquid phase oxidation was conducted with Co(CH...Liquid phase oxidation of toluene is an environmental benign route for the production of benzoic acid.In a φ48mm bubble column reactor,the commercial process of toluene liquid phase oxidation was conducted with Co(CH3COO)2.4H2O as catalyst.The Co2+ concentration [Co2+] was determined by extraction spectrophotometry and hereby the Co3+ concentration [Co3+] was obtained by mass balance.The results showed that [Co3+] reached the maximum at about 25-30min.[Co3+] increased with increasing Co catalyst amount at total Co concentration<150 mg.L-1 of toluene.The conversion of toluene,yield and selectivity of benzoic acid increased with the increasing [Co3+/Co2+] max.A high [Co3+] and a high [Co3+]/[Co2+] ratio are beneficial to the reaction.展开更多
Pt/CeO2–ZrO2–SnO2/γ-Al2O3 catalysts were prepared by co-precipitation and wet impregnation methods for catalytic oxidation of acetaldehyde to acetic acid in water. In the present catalysts, Pt and CeO2–ZrO2–SnO2 ...Pt/CeO2–ZrO2–SnO2/γ-Al2O3 catalysts were prepared by co-precipitation and wet impregnation methods for catalytic oxidation of acetaldehyde to acetic acid in water. In the present catalysts, Pt and CeO2–ZrO2–SnO2 were successfully dispersed on the γ-Al2O3 support.Dependences of platinum content and reaction time on the selective oxidation of acetaldehyde to acetic acid were investigated to optimize the reaction conditions for obtaining both high acetaldehyde conversion and highest selectivity to acetic acid. Among the catalysts, a Pt（6.4 wt.%）/Ce0.68Zr0.17Sn0.15O2.0（16 wt.%）/γ-Al2O3 catalyst showed the highest acetaldehyde oxidation activity. On this catalyst, acetaldehyde was completely oxidized after the reaction at 0°C for 8 hr, and the selectivity to acetic acid reached to 95%and higher after the reaction for 4 hr and longer.展开更多
During the liquid-phase oxidation of p-xylene,over-oxidation of reactant,intermediates and solvent to carbon dioxide and carbon monoxide is generally known as the burning side reaction.Batch and semi-continuous experi...During the liquid-phase oxidation of p-xylene,over-oxidation of reactant,intermediates and solvent to carbon dioxide and carbon monoxide is generally known as the burning side reaction.Batch and semi-continuous experiments were carried out,and the experimental data of the burning side reaction were analyzed and reported in this paper.The results showed that the rates of burning side reactions were proportional to the rates of the main reaction,but decreased with the increasing concentrations of reactant and intermediates.The inter-stimulative and competitive relationship between the burning side reaction and the main reaction was confirmed,and the rates of the burning side reaction could be described with some key indexes of the main reaction.According to the mechanism of the side reactions and the kinetics model of main reaction which were proposed and tested in the previous papers,a kinetic model of the burning side reactions involving some key indexes of the main reaction was developed,and the parameters were determined by data fitting of the COx rate curves.The obtained kinetic model could describe the burning side reactions adequately.展开更多
The effect of liquid-phase oxidation impurities on the solubility of water in hydrocarbon fuels was studied.The results show that the concentration of polar surfactant molecules in the first region increases(true solu...The effect of liquid-phase oxidation impurities on the solubility of water in hydrocarbon fuels was studied.The results show that the concentration of polar surfactant molecules in the first region increases(true solution)during fuel oxidation,and since the oxidation groups(-COOH,-O=O,-OH,etc.)have similar dipole momentμ,the dielectric loss tangent tanδincreases linearly in this region with surfactant concentration.Upon further oxidation,micelle structures begin to form at a certain point.Micelle formation leads to a sharp decrease in the dipole moment attributable to the monomer unitμ/n,where nis the number of molecules in a micelle.A several-fold decrease in the dipole moment leads to a sharp drop in tanδ.Upon further increase in the number and size of micelles,the dipole moment remains practically unchanged,and the dielectric loss tangent begins to increase linearly again with surfactant concentration.If the critical concentration for micelle formation is achieved upon further oxidation of hydrocarbon liquids,micelle formation processes occur spontaneously in the solution,and the true solution becomes a colloidal system(sol).The resulting micelles are structured with hydrocarbon radicals of molecules toward the outside and hydrophilic(polar)groups toward the inside.Water molecules are located inside micelles and held so securely that water molecules do not aggregate as temperature decreases.The reason for significant differences in the equilibrium solubility of water in hydrocarbon fuels is the different oxidation factors of product samples,resulting from the accumulation of various concentrations of oxidation products,which are natural surfactants,in hydrocarbon fuels.展开更多
Pitch produced by the lique-faction of coal was divided into two frac-tions:soluble in toluene(TS)and insol-uble in toluene but soluble in pyridine(TI-PS),and their differences in molecu-lar structure and oxidation ac...Pitch produced by the lique-faction of coal was divided into two frac-tions:soluble in toluene(TS)and insol-uble in toluene but soluble in pyridine(TI-PS),and their differences in molecu-lar structure and oxidation activity were studied.Several different carbon materi-als were produced from them by oxida-tion in air(350℃,300 mL/min)fol-lowed by carbonization(1000℃ in Ar),and the effect of the cross-linked structure on their structure and sodium storage properties was investigated.The results showed that the two pitch fractions were obviously different after the air oxidation.The TS fraction with a low degree of condensation and abundant side chains had a stronger oxidation activity and thus introduced more cross-linked oxygen-containing functional groups C(O)―O which prevented carbon layer rearrangement during the carbonization.As a result,a disordered hard carbon with more defects was formed,which improved the electrochemical performance.Therefore,the carbon materials derived from TS(O-TS-1000)had an obvious disordered structure and a larger layer spacing,giving them better sodium storage perform-ance than those derived from the TI-PS fraction(O-TI-PS-1000).The specific capacity of O-TS-1000 was about 250 mAh/g at 20 mA/g,which was 1.67 times higher than that of O-TI-PS-1000(150 mAh/g).展开更多
Up-and-coming high-temperature materials,refractory high entropy alloys,are suffering from lower oxidation resistance,restricting their applications in the aerospace field.In this study,two novel treatments of Al-depo...Up-and-coming high-temperature materials,refractory high entropy alloys,are suffering from lower oxidation resistance,restricting their applications in the aerospace field.In this study,two novel treatments of Al-deposited and remelted were developed to refine the microstructure and enhance the oxidation resistance of refractory high entropy alloy using electron beam freeform fabrication(EBF3).Finer and short-range ordering structures were observed in the remelted sample,whereas the Al-deposited sample showcased the formation of silicide and intermetallic phases.High-temperature cyclic and isothermal oxidation tests at 1000℃ were carried out.The total weight gain after 60 h of cyclic oxidation decreased by 17.49%and 30.46%for the remelted and deposited samples,respectively,compared to the as-cast state.Oxidation kinetics reveal an evident lower mass gain and oxidation rate in the treated samples.A multilayer oxide consisting of TiO_(2)+Al_(2)O_(3)+SiO_(2)+AlNbO_(4) was studied for its excellent oxidation resistance.The oxidation behavior of rutile,corundum and other oxides was analyzed using first principles calculations and chemical defect analysis.Overall,this research,which introduces novel treatments,offers promising insights for enhancing the inherent oxidation resistance of refractory high entropy alloys.展开更多
The novel Co-based superalloys are extensively used in gas-powered and jet engine turbines due to their excellent high-temperature performance, achieved by strengthening the L12-γ′ ordered phase. This review present...The novel Co-based superalloys are extensively used in gas-powered and jet engine turbines due to their excellent high-temperature performance, achieved by strengthening the L12-γ′ ordered phase. This review presents an overview of the research progress on oxidation behavior of Co-based superalloys, including oxidation kinetics, oxides morphology, the formation and spallation of oxide layers, and importantly, the synergistic effects of alloying elements on oxidation resistance—a critical area considering the complex interactions with multiple alloying elements. Additionally, this review compares the oxidation resistance of single crystal versus polycrystalline alloys. The effect of phase interface and dislocations on oxidation behavior is also discussed. While significant progress has been achieved, areas necessitating further investigation include optimizing alloy compositions for enhanced oxidation resistance and understanding the long-term stability of oxide layers. The future prospects for Co-based superalloys are promising as ongoing research aims to address the existing challenges and unlock new applications at even higher operating temperatures.展开更多
Traumatic brain injury involves complex pathophysiological mechanisms,among which oxidative stress significantly contributes to the occurrence of secondary injury.In this study,we evaluated hypidone hydrochloride(YL-0...Traumatic brain injury involves complex pathophysiological mechanisms,among which oxidative stress significantly contributes to the occurrence of secondary injury.In this study,we evaluated hypidone hydrochloride(YL-0919),a self-developed antidepressant with selective sigma-1 receptor agonist properties,and its associated mechanisms and targets in traumatic brain injury.Behavioral experiments to assess functional deficits were followed by assessment of neuronal damage through histological analyses and examination of blood-brain barrier permeability and brain edema.Next,we investigated the antioxidative effects of YL-0919 by assessing the levels of traditional markers of oxidative stress in vivo in mice and in vitro in HT22 cells.Finally,the targeted action of YL-0919 was verified by employing a sigma-1 receptor antagonist(BD-1047).Our findings demonstrated that YL-0919 markedly improved deficits in motor function and spatial cognition on day 3 post traumatic brain injury,while also decreasing neuronal mortality and reversing blood-brain barrier disruption and brain edema.Furthermore,YL-0919 effectively combated oxidative stress both in vivo and in vitro.The protective effects of YL-0919 were partially inhibited by BD-1047.These results indicated that YL-0919 relieved impairments in motor and spatial cognition by restraining oxidative stress,a neuroprotective effect that was partially reversed by the sigma-1 receptor antagonist BD-1047.YL-0919 may have potential as a new treatment for traumatic brain injury.展开更多
Magnesium matrix composites with both high strength and ductility have been achieved by introducing pure Ti particles.However,the properties of the surfaces of the composites need to be improved by surface technology,...Magnesium matrix composites with both high strength and ductility have been achieved by introducing pure Ti particles.However,the properties of the surfaces of the composites need to be improved by surface technology,such as micro-arc oxidation(MAO).In this study,we investigated the influence of the Ti-reinforcement phase on coating growth and evolution by subjecting both AZ91 alloy and AZ91/Ti composite to MAO treatment using silicate-based and phosphate-based electrolytes.Results revealed that the Ti-reinforcement phase influenced the MAO process,altering discharge behavior,and leading to a decreased cell voltage.The vigorous discharge of the Ti-reinforcement phase induced the formation of coating discharge channels,concurrently dissolving and oxidizing Ti-reinforcement to produce a composite ceramic coating with TiO2.The MAO coating on the AZ91/Ti composite exhibited a dark blue macromorphology and distinctive local micromorphological anomalies.In silicate electrolyte,a“volcano-like”localized morphology centered on the discharge channel emerged.In contrast,treatment in phosphate-based electrolyte resulted in a coating morphology similar to typical porous ceramic coatings,with visible radial discharge micropores at the reinforcement phase location.Compared to the AZ91 alloy,the coating on the AZ91/Ti composite exhibited lower thickness and higher porosity.MAO treatment reduced the self-corrosion current density of the AZ91/Ti surface by two orders of magnitude.The silicate coating demonstrated better corrosion resistance than the phosphate coating,attributed to its lower porosity.The formation mechanism of MAO coatings on AZ91/Ti composites in phosphate-based and silicate-based electrolytes was proposed.展开更多
Nano-zinc oxides(ZnO)demonstrate remarkable antibacterial properties.To further enhance the corrosion resistance and antibacterial efficiency of magnesium alloy micro-arc oxidation(MAO)coatings,this study investigates...Nano-zinc oxides(ZnO)demonstrate remarkable antibacterial properties.To further enhance the corrosion resistance and antibacterial efficiency of magnesium alloy micro-arc oxidation(MAO)coatings,this study investigates the preparation of ZnO-containing micro-arc oxidation coatings with dual functionality by incorporating nano-ZnO into MAO electrolyte.The influence of varying ZnO concentrations on the microstructure,corrosion resistance,and antibacterial properties of the coating was examined through microstructure analysis,immersion tests,electrochemical experiments,and antibacterial assays.The findings revealed that the addition of nano-ZnO significantly enhanced the corrosion resistance of the MAO-coated alloy.Specifically,when the ZnO concentration in the electrolyte was 5 g/L,the corrosion rate was more than ten times lower compared to the MAO coatings without ZnO.Moreover,the antibacterial efficacy of ZnO+MAO coating,prepared with a ZnO concentration of 5 g/L,surpassed 95%after 24 h of co-culturing with Staphylococcus aureus(S.aureus).The nano-ZnO+MAO-coated alloy exhibited exceptional degradation resistance,corrosion resistance,and antibacterial effectiveness.展开更多
A Cr/CoNiCrAlTaY bilayer coating was prepared on the Ti-45Al-8.5Nb alloy by plasma surface metallurgy technique.The as-prepared coating with a grain size of~2μm exhibited a dense microstructure and strong adhesion du...A Cr/CoNiCrAlTaY bilayer coating was prepared on the Ti-45Al-8.5Nb alloy by plasma surface metallurgy technique.The as-prepared coating with a grain size of~2μm exhibited a dense microstructure and strong adhesion due to metallurgical bonding,consisting of outermost Cr layer and CoNiCrAlTaY transition layer.The typical power-law relationship between mass gain and time was obtained for the coated specimens with a rate exponent of 3.18 following oxidation at 1173 K.The top Cr_(2)O_(3)film and spinel oxides(i.e.,NiCr_(2)O_(4)and CoCr_(2)O_(4))exhibited a protective effect with a low oxidation reaction rate.Interfacial analysis identified Ta precipitates(Cr_(2)Ta and TaAl_(3))and Ta oxides(Ta_(2)O_(5)and Ta_(2)O_(3)),which played an essential role in retarding rapid diffusion and enhancing adhesion and oxidation resistance.展开更多
This study presents a novel approach to improving the anticorrosive performance of AZ31 Mg alloy by exploiting the role of the hydration reaction to induce interactions between Quinolin-8-ol(8HQ)molecules and the poro...This study presents a novel approach to improving the anticorrosive performance of AZ31 Mg alloy by exploiting the role of the hydration reaction to induce interactions between Quinolin-8-ol(8HQ)molecules and the porous MgO layer formed via plasma electrolytic oxidation(PEO).The AZ31 Mg alloy,initially coated with a PEO layer,underwent a dipping treatment in an ethanolic solution of 0.05 M 8HQ at 50℃ for 3 h.The results were compared with those from a different procedure where the PEO layer was subjected to a hydration reaction for 2 h at 90℃ before immersion in the 8HQ solution under the same conditions.The hydration treatment played a crucial role by converting MgO to Mg(OH)_(2),significantly enhancing the surface reactivity.This transformation introduced hydroxyl groups(−OH)on the surface,which facilitated donor-acceptor interactions with the electron-accepting sites on 8HQ molecules.The calculated binding energy(Ebinding)from DFT indicated that the interaction energy of 8HQ with Mg(OH)_(2) was lower compared to 8HQ with MgO,suggesting easier adsorption of 8HQ molecules on the hydrated surface.This,combined with the increased number of active sites and enhanced surface area,allowed for extensive surface coverage by 8HQ,leading to the formation of a stable,flake-like protective layer that sealed the majority of pores on the PEO layer.DFT calculations further suggested that the hydration treatment provided multiple active sites,enabling effective contact with 8HQ and rapid electron transfer,creating ideal conditions for charge-transfer-induced physical and chemical bonding.This study shows that hydration and 8HQ treatments significantly enhance the corrosion resistance of Mg alloys,highlighting their potential for advanced anticorrosive coatings.展开更多
Silicide coatings have proven to be promising for improving the high-temperature oxidation resistance of niobium alloy.However,the long-term protective property of single silicide coating remains a long-time endeavor ...Silicide coatings have proven to be promising for improving the high-temperature oxidation resistance of niobium alloy.However,the long-term protective property of single silicide coating remains a long-time endeavor due to the deficiency of oxygen-consuming phases,as well as the self-healing ability of the protective layer.Herein,a silicide-based composite coating is constructed on niobium alloy by incor-poration of nano-SiC particles for enhancing the high-temperature oxidation resistance.Isothermal oxi-dation results at 1250℃ for 50 h indicate that NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multilayer coated sample with a low mass gain of 2.49 mg/cm^(2) shows an improved oxidation resistance compared with NbSi_(2) coating(6.49 mg/cm^(2)).The enhanced high-temperature antioxidant performance of NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multi-layer coating is mainly attributed to the formation of the protective SiO_(2) self-healing film and the high-temperature diffusion behavior of NbSi_(2)/substrate.展开更多
Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has ...Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has been often correlated with the activity enhancement.Here,a systematic study on the roles of Fe substitution in activation of perovskite LaNiO_(3)is reported.The substituting Fe content influences both current change tendency and surface reconstruction degree.LaNi_(0.9)Fe_(0.1)O_(3)is found exhibiting a volcano-peak intrinsic activity in both pristine and reconstructed among all substituted perovskites in the LaNi_(1-x)Fe_(x)O_(3)(x=0.00,0.10,0.25,0.50,0.75,1.00)series.The reconstructed LaNi_(0.9)Fe_(0.1)O_(3)shows a higher intrinsic activity than most reported NiFe-based catalysts.Besides,density functional theory calculations reveal that Fe substitution can lower the O 2p level,which thus stabilize lattice oxygen in LaNi0.9Fe0.1O3 and ensure its long-term stability.Furthermore,it is vital interesting that activity of the reconstructed catalysts relied more on the surface chemistry rather than the reconstruction degree.The effect of Fe on the degree of surface reconstruction of the perovskite is decoupled from that on its activity enhancement after surface reconstruction.This finding showcases the importance to customize the surface chemistry of reconstructed catalysts for water oxidation.展开更多
Current research on heterogeneous advanced oxidation processes(HAOPs)predominantly emphasizes catalyst iteration and innovation.Significant efforts have been made to regulate the electron structure and optimize the el...Current research on heterogeneous advanced oxidation processes(HAOPs)predominantly emphasizes catalyst iteration and innovation.Significant efforts have been made to regulate the electron structure and optimize the electron distribution,thereby increasing the catalytic activity.However,this focus often overshadows an equally essential aspect of HAOPs:the adsorption effect.Adsorption is a critical initiator for triggering the interaction of oxidants and contaminants with heterogeneous catalysts.The efficacy of these interactions is influenced by a variety of physicochemical properties,including surface chemistry and pore sizes,which determine the affinities between contaminants and material surfaces.This dispar ity in affinity is pivotal because it underpins the selective removal of contaminants,especially in complex waste streams containing diverse contaminants and competing matrices.Consequently,understanding and mastering these interfacial interactions is fundamentally indispensable not only for improving pro cess efficiency but also for enhancing the selectivity of contaminant removal.Herein,we highlight the importance of adsorption-driven interfacial interactions for fundamentally elucidating the catalytic mechanisms of HAOPs.Such interactions dictate the overall performance of the treatment processes by balancing the adsorption,reaction,and desorption rates on the catalyst surfaces.Elucidating the adsorption effect not only shifts the paradigm in understanding HAOPs but also improves their practical ity in water treatment and wastewater decontamination.Overall,we propose that revisiting adsorption driven interfacial interactions holds great promise for optimizing catalytic processes to develop effective HAOP strategies.展开更多
Herein,a series of manganese oxide catalysts with different valences(Mn_(3)O_(4),Mn_(2)O_(3),and MnO_(2))were designed and synthesized for the synthesis of ethylene urea(EU)from ethylenediamine(EDA)and carbon dioxide(...Herein,a series of manganese oxide catalysts with different valences(Mn_(3)O_(4),Mn_(2)O_(3),and MnO_(2))were designed and synthesized for the synthesis of ethylene urea(EU)from ethylenediamine(EDA)and carbon dioxide(CO_(2)).With a maximal EDA conversion of 82%and EU selectivity of 99%at 160℃ for 2 h,Mn_(2)O_(3) catalysts had the best catalytic activity among them,which was superior to the reported catalysts.In the following order:Mn_(2)O_(3)>MnO_(2)>Mn_(3)O_(4),the catalytic activity for the synthesis of EU from CO_(2) and EDA decreased.Further characterization showed the Mn_(2)O_(3) catalyst possessed a greater Mn^(3+)/Mn4+ratio and more surface oxygen vacancies than the MnO_(2) and Mn_(3)O_(4),which improved its capacity to adsorb and activate CO_(2) and EDA.After four recycling runs,the EDA conversion slightly declined from 82%to 56%on Mn_(2)O_(3) catalyst,while no obvious change in EU selectivity was observed.The loss of surface Ov contents and Mn^(3+)proportion were concluded as main reasons for the decrease in catalytic activity over Mn_(2)O_(3) catalyst.This work demonstrated a metal oxide catalyst that was efficient in producing EU from CO_(2) and EDA.展开更多
Establishing an energy-saving and affordable hydrogen production route from infinite seawater presents a promising strategy for achieving carbon neutrality and low-carbon development.Compared with the kinetically slug...Establishing an energy-saving and affordable hydrogen production route from infinite seawater presents a promising strategy for achieving carbon neutrality and low-carbon development.Compared with the kinetically sluggish oxygen evolution reaction(OER),the thermodynamically advantageous sulfion oxidation reaction(SOR)enables the S^(2-)pollutants recovery while reducing the energy input of water electrolysis.Here,a nanoporous NiMo alloy ligament(np-NiMo)with AlNi_(3)/Al_(5)Mo heterostructure was prepared for hydrogen evolution reaction(HER,-0.134V versus reversible hydrogen electrode(vs.RHE)at 50mA/cm^(2)),which needs an Al_(89)Ni_(10)Mo_(1)as a precursor and dealloying operation.Further,the np-NiMo alloy was thermal-treated with S powder to generate Mo-doped NiS_(2)(np-NiMo-S)for OER(1.544V vs.RHE at 50mA/cm^(2))and SOR(0.364 V vs.RHE at 50mA/cm^(2)),while still maintaining the nanostructuring advantages.Moreover,for a two-electrode electrolyzer system with np-NiMo cathode(1M KOH+seawater)coupling np-NiMo-S anode(1mol/L KOH+seawater+1 mol/L Na_(2)S),a remarkably ultra-low cell potential of 0.532 V is acquired at 50mA/cm^(2),which is about 1.015 V below that of normal alkaline seawater splitting.The theory calculations confirmed that the AlNi_(3)/Al_(5)Mo heterostructure within np-NiMo promotes H_(2)O dissociation for excellent HER,while the Mo-dopant of np-NiMo-S lowers energy barriers for the rate-determining step from^(*)S_(4)to^(*)S_(8).This work develops two kinds of NiMo alloy with tremendous prominence for achieving energy-efficient hydrogen production from alkaline seawater and sulfur recycling from sulfion-rich sewage.展开更多
We adopted the solution impregnation route with aluminum dihydrogen phosphate solution as liquid medium for effective surface modification on graphite substrate.The mass ratio of graphite to Al(H_(2)PO_(4))_(3) change...We adopted the solution impregnation route with aluminum dihydrogen phosphate solution as liquid medium for effective surface modification on graphite substrate.The mass ratio of graphite to Al(H_(2)PO_(4))_(3) changed from 0.5:1 to 4:1,and the impregnation time changed from 1 to 7 h.The typical composite phase change thermal storage materials doped with the as-treated graphite were fabricated using form-stable technique.To investigate the oxidation and anti-oxidation behavior of the impregnated graphite at high temperatures,the samples were put into a muffle furnace for a cyclic heat test.Based on SEM,EDS,DSC techniques,analyses on the impregnated technique suggested an optimized processing conditions of a 3 h impregnation time with the ratio of graphite:Al(H_(2)PO_(4))_(3) as 1:3 for graphite impregnation treatment.Further investigations on high-temperature phase change heat storage materials doped by the treated graphite suggested excellent oxidation resistance and thermal cycling performance.展开更多
Powder metallurgy was used to fabricate TiC-NiCr cermets and the oxidation behavior at 900℃ was investigated.Results reveal that TiC-NiCr cermets have uniform structures with excellent mechanical properties,whose har...Powder metallurgy was used to fabricate TiC-NiCr cermets and the oxidation behavior at 900℃ was investigated.Results reveal that TiC-NiCr cermets have uniform structures with excellent mechanical properties,whose hardness is 65 HRC and flexural strength is 1450 MPa.The high-temperature oxidation mechanism of TiC-based cermets was investigated through an X-ray diffractometer and scanning electron microscope.The added elements Ni and Cr along with their solid solutions not only bond with the hard phase TiC to ensure the physical performance of the cermet,but also impede the internal diffusion during oxidation by forming a dense composite oxide layer,thereby enhancing the oxidation resistance.The TiC-NiCr cermet exhibits a dense protective oxide layer at 900℃ and can endure continuous oxidation for approximately 1000 h.A methodology for fabricating TiC-NiCr metal matrix composites is proposed,and their oxidation resistance is evaluated,providing a theoretical and practical basis for simultaneously enhancing the mechanical properties and oxidation resistance and reducing production costs.展开更多
Although bimetallic phosphide cocatalysts have attracted considerable interest in photocatalysis research owing to their advantageous thermodynamic characteristics,superstable and efficient cocatalysts have rarely bee...Although bimetallic phosphide cocatalysts have attracted considerable interest in photocatalysis research owing to their advantageous thermodynamic characteristics,superstable and efficient cocatalysts have rarely been produced through the modulation of their structure and composition.In this study,a series of bimetallic nickel-iron phosphide(Ni_(x)Fe_(2-x)P,where 0<x<2)cocatalysts with controllable structures and overpotentials were designed by adjusting the atomic ratio of Ni/Fe onto nonmetallic elemental red phosphorus(RP)for the photocatalytic selective oxidation of benzyl alcohol(BA)coupled with hydrogen production.The catalysts exhibited an outstanding photocatalytic activity for benzaldehyde and a high H_(2)yield.The RP regulated by bimetallic phosphide cocatalysts(Ni_(x)Fe_(2-x)P)demonstrated higher photocatalytic oxidation-reduction activity than that regulated by monometallic phosphide cocatalysts(Ni_(2)P and Fe2P).In particular,the RP regulated by Ni_(1.25)Fe_(0.75)P exhibited the best photocatalytic performance.In addition,experimental and theoretical calculations further illustrated that Ni_(1.25)Fe_(0.75)P,with the optimized electronic structure,possessed good electrical conductivity and provided strong adsorption and abundant active sites,thereby accelerating electron migration and lowering the reaction energy barrier of RP.This finding offers valuable insights into the rational design of highly effective cocatalysts aimed at optimizing the photocatalytic activity of composite photocatalysts.展开更多
基金Supported by the National Natural Science Foundation of China （20576081, 20736009） and the Ph.D. Programs Foundation of Ministry of Education of China （20070610128）.
文摘Liquid phase oxidation of toluene is an environmental benign route for the production of benzoic acid.In a φ48mm bubble column reactor,the commercial process of toluene liquid phase oxidation was conducted with Co(CH3COO)2.4H2O as catalyst.The Co2+ concentration [Co2+] was determined by extraction spectrophotometry and hereby the Co3+ concentration [Co3+] was obtained by mass balance.The results showed that [Co3+] reached the maximum at about 25-30min.[Co3+] increased with increasing Co catalyst amount at total Co concentration<150 mg.L-1 of toluene.The conversion of toluene,yield and selectivity of benzoic acid increased with the increasing [Co3+/Co2+] max.A high [Co3+] and a high [Co3+]/[Co2+] ratio are beneficial to the reaction.
文摘Pt/CeO2–ZrO2–SnO2/γ-Al2O3 catalysts were prepared by co-precipitation and wet impregnation methods for catalytic oxidation of acetaldehyde to acetic acid in water. In the present catalysts, Pt and CeO2–ZrO2–SnO2 were successfully dispersed on the γ-Al2O3 support.Dependences of platinum content and reaction time on the selective oxidation of acetaldehyde to acetic acid were investigated to optimize the reaction conditions for obtaining both high acetaldehyde conversion and highest selectivity to acetic acid. Among the catalysts, a Pt（6.4 wt.%）/Ce0.68Zr0.17Sn0.15O2.0（16 wt.%）/γ-Al2O3 catalyst showed the highest acetaldehyde oxidation activity. On this catalyst, acetaldehyde was completely oxidized after the reaction at 0°C for 8 hr, and the selectivity to acetic acid reached to 95%and higher after the reaction for 4 hr and longer.
基金Supported by the Natural National Science Foundation of China （20080672） and the Research Fund for the Doctoral Program of Higher Education of China （200803351111）.
文摘During the liquid-phase oxidation of p-xylene,over-oxidation of reactant,intermediates and solvent to carbon dioxide and carbon monoxide is generally known as the burning side reaction.Batch and semi-continuous experiments were carried out,and the experimental data of the burning side reaction were analyzed and reported in this paper.The results showed that the rates of burning side reactions were proportional to the rates of the main reaction,but decreased with the increasing concentrations of reactant and intermediates.The inter-stimulative and competitive relationship between the burning side reaction and the main reaction was confirmed,and the rates of the burning side reaction could be described with some key indexes of the main reaction.According to the mechanism of the side reactions and the kinetics model of main reaction which were proposed and tested in the previous papers,a kinetic model of the burning side reactions involving some key indexes of the main reaction was developed,and the parameters were determined by data fitting of the COx rate curves.The obtained kinetic model could describe the burning side reactions adequately.
文摘The effect of liquid-phase oxidation impurities on the solubility of water in hydrocarbon fuels was studied.The results show that the concentration of polar surfactant molecules in the first region increases(true solution)during fuel oxidation,and since the oxidation groups(-COOH,-O=O,-OH,etc.)have similar dipole momentμ,the dielectric loss tangent tanδincreases linearly in this region with surfactant concentration.Upon further oxidation,micelle structures begin to form at a certain point.Micelle formation leads to a sharp decrease in the dipole moment attributable to the monomer unitμ/n,where nis the number of molecules in a micelle.A several-fold decrease in the dipole moment leads to a sharp drop in tanδ.Upon further increase in the number and size of micelles,the dipole moment remains practically unchanged,and the dielectric loss tangent begins to increase linearly again with surfactant concentration.If the critical concentration for micelle formation is achieved upon further oxidation of hydrocarbon liquids,micelle formation processes occur spontaneously in the solution,and the true solution becomes a colloidal system(sol).The resulting micelles are structured with hydrocarbon radicals of molecules toward the outside and hydrophilic(polar)groups toward the inside.Water molecules are located inside micelles and held so securely that water molecules do not aggregate as temperature decreases.The reason for significant differences in the equilibrium solubility of water in hydrocarbon fuels is the different oxidation factors of product samples,resulting from the accumulation of various concentrations of oxidation products,which are natural surfactants,in hydrocarbon fuels.
文摘Pitch produced by the lique-faction of coal was divided into two frac-tions:soluble in toluene(TS)and insol-uble in toluene but soluble in pyridine(TI-PS),and their differences in molecu-lar structure and oxidation activity were studied.Several different carbon materi-als were produced from them by oxida-tion in air(350℃,300 mL/min)fol-lowed by carbonization(1000℃ in Ar),and the effect of the cross-linked structure on their structure and sodium storage properties was investigated.The results showed that the two pitch fractions were obviously different after the air oxidation.The TS fraction with a low degree of condensation and abundant side chains had a stronger oxidation activity and thus introduced more cross-linked oxygen-containing functional groups C(O)―O which prevented carbon layer rearrangement during the carbonization.As a result,a disordered hard carbon with more defects was formed,which improved the electrochemical performance.Therefore,the carbon materials derived from TS(O-TS-1000)had an obvious disordered structure and a larger layer spacing,giving them better sodium storage perform-ance than those derived from the TI-PS fraction(O-TI-PS-1000).The specific capacity of O-TS-1000 was about 250 mAh/g at 20 mA/g,which was 1.67 times higher than that of O-TI-PS-1000(150 mAh/g).
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0609000)National Natural Science Foundation of China(Grant Nos.52171034 and 52101037)Postdoctoral Fellowship Program of CPSFara(No.GZB20230944).
文摘Up-and-coming high-temperature materials,refractory high entropy alloys,are suffering from lower oxidation resistance,restricting their applications in the aerospace field.In this study,two novel treatments of Al-deposited and remelted were developed to refine the microstructure and enhance the oxidation resistance of refractory high entropy alloy using electron beam freeform fabrication(EBF3).Finer and short-range ordering structures were observed in the remelted sample,whereas the Al-deposited sample showcased the formation of silicide and intermetallic phases.High-temperature cyclic and isothermal oxidation tests at 1000℃ were carried out.The total weight gain after 60 h of cyclic oxidation decreased by 17.49%and 30.46%for the remelted and deposited samples,respectively,compared to the as-cast state.Oxidation kinetics reveal an evident lower mass gain and oxidation rate in the treated samples.A multilayer oxide consisting of TiO_(2)+Al_(2)O_(3)+SiO_(2)+AlNbO_(4) was studied for its excellent oxidation resistance.The oxidation behavior of rutile,corundum and other oxides was analyzed using first principles calculations and chemical defect analysis.Overall,this research,which introduces novel treatments,offers promising insights for enhancing the inherent oxidation resistance of refractory high entropy alloys.
基金support from the National Natural Science Foundation of China(Nos.52171107,52201203)the Hebei Provincial Natural Science Foundation,China(No.E2021501026)the National Natural Science Foundation of China-Joint Fund of Iron and Steel Research(No.U1960204).
文摘The novel Co-based superalloys are extensively used in gas-powered and jet engine turbines due to their excellent high-temperature performance, achieved by strengthening the L12-γ′ ordered phase. This review presents an overview of the research progress on oxidation behavior of Co-based superalloys, including oxidation kinetics, oxides morphology, the formation and spallation of oxide layers, and importantly, the synergistic effects of alloying elements on oxidation resistance—a critical area considering the complex interactions with multiple alloying elements. Additionally, this review compares the oxidation resistance of single crystal versus polycrystalline alloys. The effect of phase interface and dislocations on oxidation behavior is also discussed. While significant progress has been achieved, areas necessitating further investigation include optimizing alloy compositions for enhanced oxidation resistance and understanding the long-term stability of oxide layers. The future prospects for Co-based superalloys are promising as ongoing research aims to address the existing challenges and unlock new applications at even higher operating temperatures.
基金supported by the National Natural Science Foundation of China,Nos.82204360(to HM)and 82270411(to GW)National Science and Technology Innovation 2030 Major Program,No.2021ZD0200900(to YL)。
文摘Traumatic brain injury involves complex pathophysiological mechanisms,among which oxidative stress significantly contributes to the occurrence of secondary injury.In this study,we evaluated hypidone hydrochloride(YL-0919),a self-developed antidepressant with selective sigma-1 receptor agonist properties,and its associated mechanisms and targets in traumatic brain injury.Behavioral experiments to assess functional deficits were followed by assessment of neuronal damage through histological analyses and examination of blood-brain barrier permeability and brain edema.Next,we investigated the antioxidative effects of YL-0919 by assessing the levels of traditional markers of oxidative stress in vivo in mice and in vitro in HT22 cells.Finally,the targeted action of YL-0919 was verified by employing a sigma-1 receptor antagonist(BD-1047).Our findings demonstrated that YL-0919 markedly improved deficits in motor function and spatial cognition on day 3 post traumatic brain injury,while also decreasing neuronal mortality and reversing blood-brain barrier disruption and brain edema.Furthermore,YL-0919 effectively combated oxidative stress both in vivo and in vitro.The protective effects of YL-0919 were partially inhibited by BD-1047.These results indicated that YL-0919 relieved impairments in motor and spatial cognition by restraining oxidative stress,a neuroprotective effect that was partially reversed by the sigma-1 receptor antagonist BD-1047.YL-0919 may have potential as a new treatment for traumatic brain injury.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030006).
文摘Magnesium matrix composites with both high strength and ductility have been achieved by introducing pure Ti particles.However,the properties of the surfaces of the composites need to be improved by surface technology,such as micro-arc oxidation(MAO).In this study,we investigated the influence of the Ti-reinforcement phase on coating growth and evolution by subjecting both AZ91 alloy and AZ91/Ti composite to MAO treatment using silicate-based and phosphate-based electrolytes.Results revealed that the Ti-reinforcement phase influenced the MAO process,altering discharge behavior,and leading to a decreased cell voltage.The vigorous discharge of the Ti-reinforcement phase induced the formation of coating discharge channels,concurrently dissolving and oxidizing Ti-reinforcement to produce a composite ceramic coating with TiO2.The MAO coating on the AZ91/Ti composite exhibited a dark blue macromorphology and distinctive local micromorphological anomalies.In silicate electrolyte,a“volcano-like”localized morphology centered on the discharge channel emerged.In contrast,treatment in phosphate-based electrolyte resulted in a coating morphology similar to typical porous ceramic coatings,with visible radial discharge micropores at the reinforcement phase location.Compared to the AZ91 alloy,the coating on the AZ91/Ti composite exhibited lower thickness and higher porosity.MAO treatment reduced the self-corrosion current density of the AZ91/Ti surface by two orders of magnitude.The silicate coating demonstrated better corrosion resistance than the phosphate coating,attributed to its lower porosity.The formation mechanism of MAO coatings on AZ91/Ti composites in phosphate-based and silicate-based electrolytes was proposed.
基金supported by the National Natural Science Foundation of China(No.52001034)the China Postdoctoral Science Foundation(No.2023M731677)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX23_3032).
文摘Nano-zinc oxides(ZnO)demonstrate remarkable antibacterial properties.To further enhance the corrosion resistance and antibacterial efficiency of magnesium alloy micro-arc oxidation(MAO)coatings,this study investigates the preparation of ZnO-containing micro-arc oxidation coatings with dual functionality by incorporating nano-ZnO into MAO electrolyte.The influence of varying ZnO concentrations on the microstructure,corrosion resistance,and antibacterial properties of the coating was examined through microstructure analysis,immersion tests,electrochemical experiments,and antibacterial assays.The findings revealed that the addition of nano-ZnO significantly enhanced the corrosion resistance of the MAO-coated alloy.Specifically,when the ZnO concentration in the electrolyte was 5 g/L,the corrosion rate was more than ten times lower compared to the MAO coatings without ZnO.Moreover,the antibacterial efficacy of ZnO+MAO coating,prepared with a ZnO concentration of 5 g/L,surpassed 95%after 24 h of co-culturing with Staphylococcus aureus(S.aureus).The nano-ZnO+MAO-coated alloy exhibited exceptional degradation resistance,corrosion resistance,and antibacterial effectiveness.
基金financial supports from Shanxi Provincial Natural Science Foundation,China(No.20210302123162)Shanxi Scholarship Council of China(No.2024-057)+2 种基金State Key Laboratory of Advanced Metal Materials,China(No.2019-ZD02)Science and Technology Achievement Transformation and Cultivation Project of Shanxi,China(No.2020CG011)Shanxi“1331 Project”Quality Improvement and Efficiency Project,China。
文摘A Cr/CoNiCrAlTaY bilayer coating was prepared on the Ti-45Al-8.5Nb alloy by plasma surface metallurgy technique.The as-prepared coating with a grain size of~2μm exhibited a dense microstructure and strong adhesion due to metallurgical bonding,consisting of outermost Cr layer and CoNiCrAlTaY transition layer.The typical power-law relationship between mass gain and time was obtained for the coated specimens with a rate exponent of 3.18 following oxidation at 1173 K.The top Cr_(2)O_(3)film and spinel oxides(i.e.,NiCr_(2)O_(4)and CoCr_(2)O_(4))exhibited a protective effect with a low oxidation reaction rate.Interfacial analysis identified Ta precipitates(Cr_(2)Ta and TaAl_(3))and Ta oxides(Ta_(2)O_(5)and Ta_(2)O_(3)),which played an essential role in retarding rapid diffusion and enhancing adhesion and oxidation resistance.
基金supported by the National Research Foundation of Korea(NRF)funded by the Korean government(MSIT)(No.2022R1A2C1006743).
文摘This study presents a novel approach to improving the anticorrosive performance of AZ31 Mg alloy by exploiting the role of the hydration reaction to induce interactions between Quinolin-8-ol(8HQ)molecules and the porous MgO layer formed via plasma electrolytic oxidation(PEO).The AZ31 Mg alloy,initially coated with a PEO layer,underwent a dipping treatment in an ethanolic solution of 0.05 M 8HQ at 50℃ for 3 h.The results were compared with those from a different procedure where the PEO layer was subjected to a hydration reaction for 2 h at 90℃ before immersion in the 8HQ solution under the same conditions.The hydration treatment played a crucial role by converting MgO to Mg(OH)_(2),significantly enhancing the surface reactivity.This transformation introduced hydroxyl groups(−OH)on the surface,which facilitated donor-acceptor interactions with the electron-accepting sites on 8HQ molecules.The calculated binding energy(Ebinding)from DFT indicated that the interaction energy of 8HQ with Mg(OH)_(2) was lower compared to 8HQ with MgO,suggesting easier adsorption of 8HQ molecules on the hydrated surface.This,combined with the increased number of active sites and enhanced surface area,allowed for extensive surface coverage by 8HQ,leading to the formation of a stable,flake-like protective layer that sealed the majority of pores on the PEO layer.DFT calculations further suggested that the hydration treatment provided multiple active sites,enabling effective contact with 8HQ and rapid electron transfer,creating ideal conditions for charge-transfer-induced physical and chemical bonding.This study shows that hydration and 8HQ treatments significantly enhance the corrosion resistance of Mg alloys,highlighting their potential for advanced anticorrosive coatings.
基金supported by the National Natural Science Foundation of China(Nos.U21B2053,52071114,52001100,and 523B2010)Outstanding Youth Project of Natural Science Foundation of Heilongjiang Province(No.YQ2023E008)+1 种基金Young Elite Scientists Sponsorship Program by CAST(NO.2021QNRC001)Heilongjiang Touyan Team Program.
文摘Silicide coatings have proven to be promising for improving the high-temperature oxidation resistance of niobium alloy.However,the long-term protective property of single silicide coating remains a long-time endeavor due to the deficiency of oxygen-consuming phases,as well as the self-healing ability of the protective layer.Herein,a silicide-based composite coating is constructed on niobium alloy by incor-poration of nano-SiC particles for enhancing the high-temperature oxidation resistance.Isothermal oxi-dation results at 1250℃ for 50 h indicate that NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multilayer coated sample with a low mass gain of 2.49 mg/cm^(2) shows an improved oxidation resistance compared with NbSi_(2) coating(6.49 mg/cm^(2)).The enhanced high-temperature antioxidant performance of NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multi-layer coating is mainly attributed to the formation of the protective SiO_(2) self-healing film and the high-temperature diffusion behavior of NbSi_(2)/substrate.
基金funded by the National Key R&D Program of China(2021YFA1501101)the National Natural Science Foundation of China(No.22471103,22425105,22201111,21931001,22221001,and 22271124)+5 种基金Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)the Special Fund Project of Guiding Scientific and Technological Innovation Development of Gansu Province(2019ZX-04)the 111 Project(B20027)as well as the National Natural Science Foundation of Gansu Province(22JR5RA470)the Fundamental Research Funds for the Central Universities(lzujbky-2023-eyt03)supported by the Agency for Science,Technology and Research(A*STAR)MTC Individual Research Grants(IRG)M22K2c0078.
文摘Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has been often correlated with the activity enhancement.Here,a systematic study on the roles of Fe substitution in activation of perovskite LaNiO_(3)is reported.The substituting Fe content influences both current change tendency and surface reconstruction degree.LaNi_(0.9)Fe_(0.1)O_(3)is found exhibiting a volcano-peak intrinsic activity in both pristine and reconstructed among all substituted perovskites in the LaNi_(1-x)Fe_(x)O_(3)(x=0.00,0.10,0.25,0.50,0.75,1.00)series.The reconstructed LaNi_(0.9)Fe_(0.1)O_(3)shows a higher intrinsic activity than most reported NiFe-based catalysts.Besides,density functional theory calculations reveal that Fe substitution can lower the O 2p level,which thus stabilize lattice oxygen in LaNi0.9Fe0.1O3 and ensure its long-term stability.Furthermore,it is vital interesting that activity of the reconstructed catalysts relied more on the surface chemistry rather than the reconstruction degree.The effect of Fe on the degree of surface reconstruction of the perovskite is decoupled from that on its activity enhancement after surface reconstruction.This finding showcases the importance to customize the surface chemistry of reconstructed catalysts for water oxidation.
基金supported by the National Key Research and Development Program of China(2022YFC3205300)the National Natural Science Foundation of China(22176124).
文摘Current research on heterogeneous advanced oxidation processes(HAOPs)predominantly emphasizes catalyst iteration and innovation.Significant efforts have been made to regulate the electron structure and optimize the electron distribution,thereby increasing the catalytic activity.However,this focus often overshadows an equally essential aspect of HAOPs:the adsorption effect.Adsorption is a critical initiator for triggering the interaction of oxidants and contaminants with heterogeneous catalysts.The efficacy of these interactions is influenced by a variety of physicochemical properties,including surface chemistry and pore sizes,which determine the affinities between contaminants and material surfaces.This dispar ity in affinity is pivotal because it underpins the selective removal of contaminants,especially in complex waste streams containing diverse contaminants and competing matrices.Consequently,understanding and mastering these interfacial interactions is fundamentally indispensable not only for improving pro cess efficiency but also for enhancing the selectivity of contaminant removal.Herein,we highlight the importance of adsorption-driven interfacial interactions for fundamentally elucidating the catalytic mechanisms of HAOPs.Such interactions dictate the overall performance of the treatment processes by balancing the adsorption,reaction,and desorption rates on the catalyst surfaces.Elucidating the adsorption effect not only shifts the paradigm in understanding HAOPs but also improves their practical ity in water treatment and wastewater decontamination.Overall,we propose that revisiting adsorption driven interfacial interactions holds great promise for optimizing catalytic processes to develop effective HAOP strategies.
基金supported by the National Natural Science Foundation of China(No.22278041)the Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering(No.2022-K78)+1 种基金Jiangsu Province Key Laboratory of Fine Petrochemical Engineering(No.KF2107)the Advanced Catalysis and Green Manufacturing Collab-orative Innovation Center(No.ACGM2022-10-07)。
文摘Herein,a series of manganese oxide catalysts with different valences(Mn_(3)O_(4),Mn_(2)O_(3),and MnO_(2))were designed and synthesized for the synthesis of ethylene urea(EU)from ethylenediamine(EDA)and carbon dioxide(CO_(2)).With a maximal EDA conversion of 82%and EU selectivity of 99%at 160℃ for 2 h,Mn_(2)O_(3) catalysts had the best catalytic activity among them,which was superior to the reported catalysts.In the following order:Mn_(2)O_(3)>MnO_(2)>Mn_(3)O_(4),the catalytic activity for the synthesis of EU from CO_(2) and EDA decreased.Further characterization showed the Mn_(2)O_(3) catalyst possessed a greater Mn^(3+)/Mn4+ratio and more surface oxygen vacancies than the MnO_(2) and Mn_(3)O_(4),which improved its capacity to adsorb and activate CO_(2) and EDA.After four recycling runs,the EDA conversion slightly declined from 82%to 56%on Mn_(2)O_(3) catalyst,while no obvious change in EU selectivity was observed.The loss of surface Ov contents and Mn^(3+)proportion were concluded as main reasons for the decrease in catalytic activity over Mn_(2)O_(3) catalyst.This work demonstrated a metal oxide catalyst that was efficient in producing EU from CO_(2) and EDA.
基金financially supported by the Guangxi Natural Science Fund for Distinguished Young Scholars(No.2024GXNSFFA010008)the Natural Science Foundation of Jilin Province of China(No.20240101098JC)the National Natural Science Foundation of China(No.22469002)。
文摘Establishing an energy-saving and affordable hydrogen production route from infinite seawater presents a promising strategy for achieving carbon neutrality and low-carbon development.Compared with the kinetically sluggish oxygen evolution reaction(OER),the thermodynamically advantageous sulfion oxidation reaction(SOR)enables the S^(2-)pollutants recovery while reducing the energy input of water electrolysis.Here,a nanoporous NiMo alloy ligament(np-NiMo)with AlNi_(3)/Al_(5)Mo heterostructure was prepared for hydrogen evolution reaction(HER,-0.134V versus reversible hydrogen electrode(vs.RHE)at 50mA/cm^(2)),which needs an Al_(89)Ni_(10)Mo_(1)as a precursor and dealloying operation.Further,the np-NiMo alloy was thermal-treated with S powder to generate Mo-doped NiS_(2)(np-NiMo-S)for OER(1.544V vs.RHE at 50mA/cm^(2))and SOR(0.364 V vs.RHE at 50mA/cm^(2)),while still maintaining the nanostructuring advantages.Moreover,for a two-electrode electrolyzer system with np-NiMo cathode(1M KOH+seawater)coupling np-NiMo-S anode(1mol/L KOH+seawater+1 mol/L Na_(2)S),a remarkably ultra-low cell potential of 0.532 V is acquired at 50mA/cm^(2),which is about 1.015 V below that of normal alkaline seawater splitting.The theory calculations confirmed that the AlNi_(3)/Al_(5)Mo heterostructure within np-NiMo promotes H_(2)O dissociation for excellent HER,while the Mo-dopant of np-NiMo-S lowers energy barriers for the rate-determining step from^(*)S_(4)to^(*)S_(8).This work develops two kinds of NiMo alloy with tremendous prominence for achieving energy-efficient hydrogen production from alkaline seawater and sulfur recycling from sulfion-rich sewage.
基金Funded by Scientific and Technological Innovation Project of Carbon Emission Peak and Carbon Neutrality of Jiangsu Province(No.BE2022028-4)。
文摘We adopted the solution impregnation route with aluminum dihydrogen phosphate solution as liquid medium for effective surface modification on graphite substrate.The mass ratio of graphite to Al(H_(2)PO_(4))_(3) changed from 0.5:1 to 4:1,and the impregnation time changed from 1 to 7 h.The typical composite phase change thermal storage materials doped with the as-treated graphite were fabricated using form-stable technique.To investigate the oxidation and anti-oxidation behavior of the impregnated graphite at high temperatures,the samples were put into a muffle furnace for a cyclic heat test.Based on SEM,EDS,DSC techniques,analyses on the impregnated technique suggested an optimized processing conditions of a 3 h impregnation time with the ratio of graphite:Al(H_(2)PO_(4))_(3) as 1:3 for graphite impregnation treatment.Further investigations on high-temperature phase change heat storage materials doped by the treated graphite suggested excellent oxidation resistance and thermal cycling performance.
基金National Natural Science Foundation of China(52376076)Open Fund of Material Corrosion and Protection Key Laboratory of Sichuan Province(2023CL13)Laiwu Vocational and Technical College Teachers Research Fund(2023jsky05)。
文摘Powder metallurgy was used to fabricate TiC-NiCr cermets and the oxidation behavior at 900℃ was investigated.Results reveal that TiC-NiCr cermets have uniform structures with excellent mechanical properties,whose hardness is 65 HRC and flexural strength is 1450 MPa.The high-temperature oxidation mechanism of TiC-based cermets was investigated through an X-ray diffractometer and scanning electron microscope.The added elements Ni and Cr along with their solid solutions not only bond with the hard phase TiC to ensure the physical performance of the cermet,but also impede the internal diffusion during oxidation by forming a dense composite oxide layer,thereby enhancing the oxidation resistance.The TiC-NiCr cermet exhibits a dense protective oxide layer at 900℃ and can endure continuous oxidation for approximately 1000 h.A methodology for fabricating TiC-NiCr metal matrix composites is proposed,and their oxidation resistance is evaluated,providing a theoretical and practical basis for simultaneously enhancing the mechanical properties and oxidation resistance and reducing production costs.
文摘Although bimetallic phosphide cocatalysts have attracted considerable interest in photocatalysis research owing to their advantageous thermodynamic characteristics,superstable and efficient cocatalysts have rarely been produced through the modulation of their structure and composition.In this study,a series of bimetallic nickel-iron phosphide(Ni_(x)Fe_(2-x)P,where 0<x<2)cocatalysts with controllable structures and overpotentials were designed by adjusting the atomic ratio of Ni/Fe onto nonmetallic elemental red phosphorus(RP)for the photocatalytic selective oxidation of benzyl alcohol(BA)coupled with hydrogen production.The catalysts exhibited an outstanding photocatalytic activity for benzaldehyde and a high H_(2)yield.The RP regulated by bimetallic phosphide cocatalysts(Ni_(x)Fe_(2-x)P)demonstrated higher photocatalytic oxidation-reduction activity than that regulated by monometallic phosphide cocatalysts(Ni_(2)P and Fe2P).In particular,the RP regulated by Ni_(1.25)Fe_(0.75)P exhibited the best photocatalytic performance.In addition,experimental and theoretical calculations further illustrated that Ni_(1.25)Fe_(0.75)P,with the optimized electronic structure,possessed good electrical conductivity and provided strong adsorption and abundant active sites,thereby accelerating electron migration and lowering the reaction energy barrier of RP.This finding offers valuable insights into the rational design of highly effective cocatalysts aimed at optimizing the photocatalytic activity of composite photocatalysts.
