激光等离子体中超金属氧化物离子LiZnO^+的产生

By 355 nm laser ablating a composite target prepared from metallic lithium and ZnO in high vaccum, a new hypermetallic oxide LiZnO + ion, which consists of two heterometal atoms and oxygen atom, was observed by using a time of flight mass spectrometer for the first time. The time of flight positive ion mass spectra at different delay time between the accelerated electric field and laser pulse are investigated. It shows that the formation of LiOZn + depends on the delay time, and the hypervalent ion LiOZn + is observed obviously at the delay time from 7.5 to 17.5 μs. These results suggest that the ion molecular reaction between the ablated Li + ions and ZnO in the laser plasma should be responsible for the formation of hypermetallic LiZnO +.

天然有机质-金属离子/氧化物-磷复合物的研究进展

天然有机质-金属离子/氧化物-磷(NOM-Metal-P)复合物作为一种广泛存在于天然水体和土壤环境中的磷素形态,其环境行为对磷素在环境中迁移转化过程发挥着重要作用。鉴于此,在综述NOM-Metal-P复合物的结合方式、测定方法、分子质量大小、生物有效性和稳定性影响因素等相关研究进展的基础上,对NOM-Metal-P复合物研究做出展望。已有研究表明,NOM-Metal-P复合物形态磷可占土壤溶液或天然水体中磷总量的50%,有时甚至达80%;NOM-Metal-P复合物的结合方式主要为NOM和P以Metal作为键桥结合形成;目前多采用截留分子质量为500或1000Da的滤膜来分离游离磷酸盐和复合物形态磷;复合物形态磷能抑制磷的固定,增强磷在环境中的迁移能力,其作为磷肥的生物利用效率大于单一磷酸盐磷肥;复合物形态磷的稳定性受紫外光照、pH和共存离子等因素的影响。

钾离子电池锰基层状氧化物正极的研究进展

可再生能源替代传统化石燃料的研究推动了电能存储系统的发展。随着对规模储能的需求不断增加,钾离子电池(PIBs)因其成本低廉、元素丰度高、理论工作电压高以及电解液中K+卓越的传输动力学,在未来将成为商用锂离子电池的补充或替代品。电极材料的发展深刻影响电池的电化学性能。石墨作为钾离子电池负极展现出了优异的循环稳定性,然而,找到具有快速的传输动力学和稳定的框架结构来嵌入/脱嵌大尺寸K^(+)的正极材料是钾离子电池面临的主要挑战。层状过渡金属氧化物因其结构稳定、合成过程简单及价格低廉等优点而具有广阔的应用前景。本文介绍了钾含量和合成温度等对过渡金属层状氧化物晶体结构的影响,并说明了各种晶体结构在脱钾过程中的结构演变和容量损失机理;在此基础上,提出了针对不同晶体结构的锰基过渡金属层状氧化物的改性方法以提高其电化学性能;最后,对新型过渡金属层状氧化物正极的主要研究方向和研究热点进行了预测,以指导未来钾离子电池正极材料的发展。

离子掺杂对钙质膨胀剂熟料性能的影响

研究了MgO、Al_(2)O_(3)和CuO三种金属离子氧化物对氧化钙类膨胀剂熟料性能的影响,与未外掺金属离子氧化物相比,分别外掺3%金属离子氧化物后,CuO抑制了膨胀剂熟料反应速率,MgO对膨胀剂熟料反应速率基本无影响,Al_(2)O_(3)加速了膨胀剂熟料的反应速率。采用化学分析、XRD、微量热法对膨胀剂熟料的f-CaO含量、矿物组成及水化历程进行了分析,结果表明,外掺CuO会抑制生料中CaCO_(3)分解为f-CaO,导致膨胀剂熟料反应速率较低;外掺MgO、Al_(2)O_(3)主要在膨胀剂熟料体系中发生离子置换反应,因Al^(3+)与Ca^(2+)价位不同使体系内部产生缺陷,提高了其膨胀反应速率。

A method for calculation of ion distribution in reaction system forming hydroxide

A formula was proposed to calculate the distribution of metal ions quantitatively in chemical reaction system forming hydroxide where precipitation and complex are formed together. The effects of some factors on formation of precipitation and complex were investigated, and the corresponding precipitation rates of zinc, iron （III）, aluminum, copper and magnesium were calculated. As a result, it shows that the proposed formula is reliable. By the proposed formula, the existence state of metal ions in hydroxides reaction system with any metal ions can be well described and the effects of some factors on the distribution of metal ions were determined.

Synthesis and physico-chemical properties of new green electrolyte 1-butyl-3-methylimidazolium perchlorate

1-butyl-3-methylimidazolium perchlorate([BMIM]ClO4) was synthesized by two steps with N-methylimidazolium.Some physico-chemical properties,such as density,surface tension,viscosity,electrical conductivity as well as electrochemical window,were investigated and solvent performance was also studied.The results show that this kind of ionic liquid is an excellent electrolyte with low viscosity,high electrical conductivity and wide electrochemical window.In addition,[BMIM]ClO4 is soluble in most conventional solvents and some metal oxides have high solubility in it,which lays the foundation of direct electrolysis of metal oxides in this ionic liquid.

Application of ionic liquids in hydrometallurgy of nonferrous metals

Ionic liquids as green solvents have shown important application in the extraction and separation of nonferrous metals.The new application perspective,the important fundamental and the applied studies of the extraction and separation of nonferrous metals in ionic liquids,including the dissolution and corrosion of metal and metal oxide,hydrometallurgy of chalcopyrite and metallic oxidized ore,and extraction and separation of metal ions,are introduced.

Electronic structure regulation on layered double hydroxides for oxygen evolution reaction

Oxygen evolution reactions(OERs)as core components of energy conversion and storage technology systems,such as water splitting and rechargeable metal–air batteries,have attracted considerable attention in recent years.Transition metal compounds,particularly layered double hydroxides(LDHs),are considered as the most promising electrocatalysts owing to their unique two-dimensional layer structures and tunable components.However,heir poor intrinsic electrical conductivities and the limited number of active sites hinder their performances.The regulation of the electronic structure is an effective approach to improve the OER activity of LDHs,including cationic and anionic regulation,defect engineering,regulation of intercalated anions,and surface modifications.In this review,we summarize recent advances in the regulation of the electronic structures of LDHs used as electrocatalysts in OERs.In addition,we discuss the effects of each regulation type on OER activities.This review is expected to shed light on the development and design of effective OER electrocatalysts by summarizing various electronic structure regulation pathways and the effects on their catalytic performances.

Designed synthesis of cobalt-oxide-based nanomaterials for superior electrochemical energy storage devices

Cobalt oxides, such as C0304 and CoO, have received increasing attention as potential anode materials for rechargeable lithium-ion batteries （LIBs） owing to their high theoretical capacity. Nanostructure engineering has been demonstrated as an effective approach to improve the electrochemical performance of electrode materials for LIBs. In this review, we summarize recent developments in the rational design and fabrication of various cobalt oxide-based nanomaterials and their lithium storage performance, including 1D nanowires/belts, 2D nanosheets, 3D hollow/hierarchical structures, hybrid nanostructures with carbon （amorphous carbon, carbon nanotubes and graphene） and mixed metal oxides. By focusing on the effects of their structure on their electrochemical performance, effective strategies for the fabrication of cobalt oxide/carbon hybrid nanostructures are highlighted. This review shows that by rational design, such cobalt-oxide-based nanornaterials are very promising as next generation LIB anodes.

Dense and pure high-entropy metal diboride ceramics sintered from self-synthesized powders via boro/carbothermal reduction approach

Equimolar quinary diboride powders,with nominal composition of(Ti0.2 Hf0.2 Zr0.2 Nb0.2 Ta0.2)B2,were synthesized by boro/carbothermal reduction(BCTR)of oxide mixtures(MOx,M=Ti,Hf,Zr,Nb and Ta)using B4 C as source of B and C in vacuum.By adjusting the B4 C/MOxratios,diboride mixtures without detectable MOxwere obtained at 1600℃,while high-entropy diboride(HEB)powders with particle size of<1μm was obtained at 1800℃.The phase,morphology and solid solution evolution process of the HEB powders during the BCTR process were comprehensively investigated.Although X-ray diffraction pattern indicated the powders synthesized at 1800℃ were in a single-phase Al B2 structure,elemental mappings showed that(Ta,Ti)-rich and(Zr,Nb)-rich solid solution coexisted in the HEB powders.The distribution of niobium and zirconium atoms in HEB was unable to reach uniform until the HEB powders were spark plasma sintered at 2000°C.(Ti0.2 Hf0.2 Zr0.2 Nb0.2 Ta0.2)B2 ceramics with a relative density of 97.9%were obtained after spark plasma sintering the HEB powders at 2050℃ under 50 MPa.Rapid grain growth was found in this composition when the sintering temperature was increased from 2000 to 2050℃,and the averaged grain size increased from 6.67 to 41.2μm.HEB ceramics sintered at 2000℃ had a Vickers hardness of 22.44±0.56 GPa(under a load of 1 kg),a Young’s modulus of^500 GPa and a fracture toughness of 2.83±0.15 MPa m1/2.This is the first report for obtaining high density HEB ceramics without residual oxide phase,benefiting from the high quality HEB powders obtained.

Nanostructured transition metal oxides as advanced anodes for lithium-ion batteries

The exploration for post-carbon electrode ma- terials for lithium-ion batteries has been a crucial way to satisfy the ever-growing demands for better performance with higher energy/power densities, enhanced safety, and longer cycle life. Transition metal oxides have recently re- ceived a great deal of attention as very promising anode materials due to their high theoretical capacity, good safety, eco-benignity, and huge abundance. The present work re- views the latest advances in developing novel transition metal oxides, including FeeO3, Fe3O4, CO3O4, CoO, NiO, MnO, Mn203, Mn3O4, MnO2, MOO3, Cr2O3, Nb2O5, and some binary oxides such as NiCO2O4, ZnCO2O4, MnCO2O4 and CoMn2O4. Nanostructuring and hybrid strategies ap- plicable to transition metal oxides are summarized and analyzed. Furthermore, the impacts of binder choice and heat treatment on electrochemical performance are discussed.

Three-dimensional porous graphene-metal oxide composite microspheres： Preparation and application in Li-ion batteries

The use of new three-dimensional （3D） porous graphene-metal oxide composite microspheres as an anode material for Li-ion batteries （LIBs） is first introduced here. 3D graphene microspheres are aggregates of individual hollow graphene nanospheres composed of graphene sheets. Metal oxide nanocrystals are uniformly distributed over the graphene surface of the microspheres. The 3D porous graphene-SnO2 microspheres are selected as the first target material for investigation because of their superior electrochemical properties. The 3D porous graphene-SnO2 and graphene microspheres and bare SnO2 powders deliver discharge capacities of 1,009, 196, and 52 mAh·g^-1, respectively, after 500 cycles at a current density of 2 A·g^-1 .The 3D porous graphene-SnO2 microspheres exhibit uniquely low charge transfer resistances and high Li-ion diffusivities before and after cycling.

Resolving the hydrothermal signature by sequential leaching studies of sediments from the middle of the Okinawa Trough

A sediment core H9 collected from the middle of the Okinawa Trough was studied by sequential leaching to indentify the hy- drothermal component from the various other components such as detrital, biogenic, and so on. The elements were partitioned into five fractions： exchangeable, bound to carbonates, bound to iron and manganese oxides, bound to organic matter, and re- sidual. The contents of elements A1, Ti, K, Fe, Mn, Pb, Co, Cu, Ni, and V in each fraction were determined and their percent- ages were calculated. Residual fraction is a dominant speciation for most studied elements except for Mn and Pb in the core sediments. For the elements A1, Ti, and K, residual fraction accounts for more than 95% of the total metal concentration. The concentrations of all studied elements in the exchangeable fraction, carbonate fraction, and organic fraction are relatively low. The metal levels in the iron and manganese oxide fraction are relatively high and this fraction represents another prevalent speciation. Also in this fraction, the metal concentrations and percentages are higher in the core section above 80 cm than those below 80 cm. Especially for Mn and Pb, the fractions bound to iron and manganese oxides account for more than 50% of the total metal concentration for the upper 80 cm section. Hydrothermal components mainly occur in this fraction. And the downcore variations of metal contents and percentages reflect the variations of hydrothermal inputs to the sediments. The high metal levels in the upper core indicate the enhancing influence of hydrothermal activities around on the core H9 during its late stage of sedimentation. The accumulation rates of hydrothermally derived Fe, Mn, Pb, Co, Cu, Ni, and V were evaluated based on their concentrations in the iron and manganese oxide fractions in this study. The results show that the accumulation rate of hydrothermally derived Mn is similar to those obtained from the Mid-ocean Ridges and Lau Basin. However, hydrothermally derived Fe and Cu present a relatively lower level.

Electronic structure evolutions driven by oxygen vacancy in SrCoO3-x films

Ionic defects, such as oxygen vacancies, play a crucial role in the magnetic and electronic states of transition metal oxides. Control of oxygen vacancy is beneficial to the technological applications, such as catalysis and energy conversion. Here, we investigate the electronic structure of SrCoO3-x as a function of oxygen content(x). We found that the hybridization extent between Co 3d and O 2p increased with the reduction of oxygen vacancies. The valence band maximum of SrCoO2.5+δ has a typical O 2p characteristic. With further increasing oxygen content, the Co ions transform from a high spin Co3+ to an intermediate spin Co4+, resulting in a transition of SrCoO3-x from insulator to metal. Our results on the electronic structure evolution with the oxygen vacancies in SrCoO3-x not only illustrate a spin state transition of Co ions,but also indicate a perspective application in catalysis and energy field.

Metal Oxide/graphene composite anode materials for lithium-ion batteries

Metal oxides, such as SnO2, Fe2O3, Fe3O4, CoO, Co3O4, NiO, CuO, Cu2O, MnO, Mn3O4, MnO2. etc. , are promising anode materi- als for lithium-ion batteries （LIBs） due to their high capacity and safety characteristics. However, the commercial utility of metal oxide anodes has been hindered to date by their poor cycling per- formance. Recent study shows that metal oxide/ graphene composites show fascinating cycling per- formance as anode materials for lABs. In this re- view, we summarize the state of research on prepa- ration of metal oxide/graphene composites and their I.i storage performance. The prospects and future challenges of metal oxide/graphene compos- ites anode materials for lABs are also discussed.

Experimental characterization of the bipolar effect on P-hit single-event transients in 65 nm twin-well and triple-well CMOS technologies

Single-event charge collection is controlled by drift, diffusion and the bipolar effect. Previous work has established that the bipolar effect is significant in the p-type metal-oxide-semiconductor field-effect transistor(PMOS) in 90 nm technology and above. However, the consequences of the bipolar effect on P-hit single-event transients have still not completely been characterized in 65 nm technology. In this paper, characterization of the consequences of the bipolar effect on P-hit single-event transients is performed by heavy ion experiments in both 65 nm twin-well and triple-well complementary metal-oxide-semiconductor(CMOS) technologies. Two inverter chains with clever layout structures are explored for the characterization. Ge(linear energy transfer(LET) = 37.4 Me V cm^2/mg) and Ti(LET = 22.2 Me V cm^2/mg) particles are also employed. The experimental results show that with Ge(Ti) exposure, the average pulse reduction is 49 ps(45 ps) in triple-well CMOS technology and 42 ps(32 ps) in twin-well CMOS technology when the bipolar effect is efficiently mitigated. This characterization will provide an important reference for radiation hardening integrated circuit design.

In situ construction of amorphous hierarchical iron oxyhydroxide nanotubes via selective dissolution-regrowth strategy for enhanced lithium storage

The low-cost and high-capacity metal oxides/oxyhydroxides possess great merits as anodes for lithium-ion batteries(LIBs)with high energy density.However,their commercialization is greatly hindered by insufficient rate capability and cyclability.Rational regulations of metal oxides/oxyhydroxides with hollow geometry and disordered atomic frameworks represent efficient ways to improve their electrochemical properties.Herein,we propose a fast alkalietching method to realize the in-situ fabrication of iron oxyhydroxide with one-dimensional(1D)hierarchical hollow nanostructure and amorphous atomic structure from the iron vanadate nanowires.Benefiting from the improved electron/ion kinetics and efficient buffer ability for the volumetric change during the electro-cycles both in nanoscale and atomic level,the graphene-modified amorphous hierarchical FeOOH nanotubes(FeOOH-NTs)display high rate capability(~650 mA h g^−1 at 2000 mA g^−1)and superior long-term cycling stability(463 mA h g^−1 after 1800 cycles),which represents the best cycling performance among the reported FeOOH-based materials.More importantly,the selective dissolutionregrowth mechanism is demonstrated based on the time tracking of the whole transition process,in which the dissolution of FeVO4 and the in-situ selective re-nucleation of FeOOH during the formation of FeOOH-NTs play the key roles.The present strategy is also a general method to prepare various metal(such as Fe,Mn,Co,and Cu)oxides/oxyhydroxides with 1D hierarchical nanostructures.