Preparation of nano-sized cerium and titanium pyrophosphates via solid-state reaction at room temperature

Nano-sized cerium-titanium pyrophosphates Ce1-xTixP2O7 （with x = 0, 0.2, 0.5, 0.7, 0.9, and 1.0） were obtained by grinding a mixture of Ce（SO4）2·4H2O, Ti（SO4）2, and Na4P2O7·10H2O in the presence of surfactant PEG-400 at room temperature, washing the mixture with water to remove soluble inorganic salts, and drying at 100℃. The products and their calcined samples were characterized using ultraviolet-visible spectroscopy （UV-vis）, thermogravimetry and differential thermal analyses （TG/DTA）, X-ray powder diffraction （XRD）, and transmission electron microscopy （TEM）. The results show that nano-sized Ce1-xTixP2O7 behave as an excellent UV-shielding material. Thereinto, the CeP2O7 has the most excellent UV-shielding effect, and the amorphous state of Ce0.8Ti0.2P2O7 can keep at a higher temperature than CeP2O7. Therefore, the stabilization of the amorphous state of the cerium pyrophosphates was carded out by doping titanium. This stabilization is a significant improvement, which enables to apply these amorphous pyrophosphates not only to cosmetics and paints, but also plastics and films.

Preparing Nano-ZnS by Solid State Reaction at Room Temperature

ZnS nanoparticles were prepared by using solid-state reaction method at room temperature in agate mortar for the first time. The average particle size was about 20nm. This reaction is affected by the structure of reactant, crystal water and defects.

Substitution Reactions by Azide and Thiocyanide Anions in Room Temperature Ionic Liquids

Conducted in the ionic liquids, activated and inactivated halides, acyl chlorides, tosylate, and bezotriazolyl acylates were converted to corresponding azide and thiocyanide compounds in high yields under mild conditions.

In situ IR, pulse reaction and TPD-ITD study of catalytic performance of room-temperature carbon monoxide oxidation on supported gold catalysts

With in situ IR, two different CO adsorption bands were detected on various chemical state gold catalysts. One band is attributed to the linear CO on an oxidized gold catalyst(2100 cm -1 ), the other one is ascribed to the bridged CO on metallic gold (2085 cm -1 ). CO pulse reaction showed that Au/Fe 2O 3 catalyst had a room temperature activity even in the presence of moisture. The produced CO 2 was detained and more easily desorbed from supported gold catalyst than support oxide. TPD IDT results indicated that the O - 2 superoxide ions are the possible active oxygen species.

Tuning composite solid-state electrolyte interface to improve the electrochemical performance of lithium-oxygen battery

Thin and flexible composite solid-state electrolyte(SSE) is considered to be a prospective candidate for lithium-oxygen(Li-O_(2)) batteries with the aim to address the problems of unsatisfied safety, terrible durability as well as inferior electrochemical performance. Herein, in order to improve the safety and durability, a succinonitrile(SN) modified composite SSE is proposed. In this SSE, SN is introduced for eliminating the boundary between ceramic particles, increasing the amorphous region of polymer and ensuring fast ionic transport. Subsequently, the symmetric battery based on the proposed SSE achieves a long cycle life of 3000 h. Moreover, the elaborate cathode interface through the SN participation effectively reduces the barriers to the combination between lithium ions and electrons, facilitating the corresponding electrochemical reactions.As a result, the solid-state Li-O_(2)battery based on this SSE and tuned cathode interface achieves improved electrochemical performance including large specific capacity over 12,000 m Ah g^(-1), enhanced rate capacity as well as stable cycle life of 54 cycles at room temperature. This ingenious design provides a new orientation for the evolution of solid-state Li-O_(2)batteries.

Role of Catalytic Materials on Conversion of Sulfur Species for Room Temperature Sodium–Sulfur Battery

Room temperature sodium–sulfur(RT Na-S)battery with high theoretical energy density and low cost has spurred tremendous interest,which is recognized as an ideal candidate for large-scale energy storage applications.However,serious sodium polysulfide shutting and sluggish reaction kinetics lead to rapid capacity decay and poor Coulombic efficiency.Recently,catalytic materials capable of adsorbing and catalyzing the conversion of polysulfides are profiled as a promising method to improve electrochemical performance.In this review,the research progress is summarized that the application of catalytic materials in RT Na-S battery.For the role of catalyst on the conversion of sulfur species,specific attention is focused on the influence factors of reaction rate during different redox processes.Various catalytic materials based on lightweight and high conductive carbon materials,including heteroatom-doped carbon,metals and metal compounds,single-atom and heterostructure,promote the reaction kinetic via lowered energy barrier and accelerated charge transfer.Additionally,the adsorption capacity of the catalytic materials is the key to the catalytic effect.Particular attention to the interaction between polysulfides and sulfur host materials is necessary for the exploration of catalytic mechanism.Lastly,the challenges and outlooks toward the desired design of efficient catalytic materials for RT Na-S battery are discussed.

Room-temperature conversion of ethane and the mechanism understanding over single iron atoms confined in graphene

The catalytic conversion of ethane to high value-added chemicals is significantly important for utilization of hydrocarbon resources.However, it is a great challenge due to the typically required high temperature(> 400 ℃) conditions.Herein, a highly active catalytic conversion process of ethane at room temperature(25 ℃) is reported on single iron atoms confined in graphene via the porphyrin-like N4-coordination structures.Combining with the operando time of flight mass spectrometer and density functional theory calculations, the reaction is identified as a radical mechanism, in which the C–H bonds of the same C atom are preferentially and sequentially activated, generating the value-added C2 chemicals, simultaneously avoiding the over-oxidation of the products to CO2.The in-situ formed O–FeN4–O structure at the single iron atom serves as the active center for the reaction and facilitates the formation of ethyl radicals.This work deepens the understanding of alkane C–H activation on the FeN4 center and provides the reference in development of efficient catalyst for selective oxidation of light alkane.

Modified room temperature solid-state synthesis of yttria-stabilized zirconia(YSZ) nano-powders for solid oxide fuel cells

High-performance solid oxide fuel cell(SOFC) is in urgent need of high-quality electrolyte powders with high reactivity and chemical uniformity.Here,8 mol% Y_(2)O_(3) doped ZrO_(2)(YSZ) nano-powders were synthesized by an improved solid-state reaction method at ambient temperature,and were applied to the fabrication of SOFC electrolytes.YSZ nano-powders show average grain sizes of ^(2)0 nm and high dispersibility,which is comparable with or even better than some other chemical methods.Benefitting from their high reactivity,dense YSZ electrolytes(relative density of 97.9%) can be obtained at a relatively low sintering temperature of 1400℃.The optimized electrical conductivity reaches up to a high value of0.034 S/cm at 800 0C in air.The anode supported single cell with the construction of Ni-YSZ/YSZ/Sm_(0.2)Ce_(0.8)O_(2-δ)(SDC)/La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF) exhibits the peak power density of 0.827 W/cm^(2) at800℃ while taking wet H_(2) as fuels and ambient air as oxidants.

Fabrication and characterization of SmO_(0.7)F_(0.2)FeAs bulk with a transition temperature of 56.5 K

The superconductivity of iron-based superconductor SmO 0.7 F 0.2 FeAs was investigated. The SmO 0.7 F 0.2 FeAs sample was prepared by the two-step solid-state reaction method. The onset resistivity transition temperature is as high as 56.5 K. X-ray diffraction （XRD） results show that the lattice parameters a and c are 0.39261 and 0.84751 nm, respectively. Furthermore, the global J c was more than 2.3 × 10 5 A/cm 2 at T = 10 K and H = 9 T, which was calculated by the formula of J c = 20ΔM/[a（1-a/（3b））]. The upper critical fields, H c2 ≈ 256 T （T = 0 K）, was determined according to the Werthamer-Helfand-Hohenberg formula, indicating that the SmO 0.7 F 0.2 FeAs was a superconductor with a very promising application.

用于常温氢氧复合的新型Pt/疏水改性陶瓷催化剂

常温氢氧复合反应由于安全性高且能耗低,在核工业除氚、消氢等领域有重要应用,其得以实现的关键为制得性能优异的疏水催化剂。为获得稳定性优且兼具高催化活性的疏水催化剂,本研究制备了新型Pt/疏水改性陶瓷催化剂。陶瓷载体通过构筑CeO2表面粗糙结构,结合涂覆低表面能十三氟辛基三甲氧基硅烷(PFOTMS)进行疏水改性,而后经浸渍-气相还原制得疏水催化剂。结果表明,与常规仅涂覆低表面能材料对陶瓷载体进行疏水改性相比,新型疏水结构的构筑不仅可使疏水催化剂获得更优的疏水性,还可进一步提升催化剂的催化活性及稳定性。制得的新型Pt/疏水改性陶瓷催化剂在480 min反应时长内,氢氧复合效率可维持在99.5%。

室温固化-高温反应增强型硅橡胶涂料

针对固体火箭发动机外防热需求,采用α,ω-二羟基聚硅氧烷为基体树脂,添加酚醛树脂粉及其他耐烧蚀填料,制备室温固化-高温反应增强型的硅橡胶涂料,研究聚硅氧烷分子链长、酚醛树脂粉含量对耐烧蚀涂料性能的影响,并进行配方优化制备轻质防隔热耐烧蚀硅橡胶涂料。采用力学性能分析、热物理常数测试、热失重分析、扫描电镜、氧-乙炔焰烧蚀等方法对涂层性能进行表征。研究表明,酚醛树脂粉可显著提升涂层的力学性能、耐烧蚀性能,涂层具备室温固化-高温反应增强特性,微观具有互相穿插的双重交联网络结构。通过对涂料进行系列配方优化,获得了综合性能较优异的防隔热耐烧蚀涂料,其具备可室温固化、轻质、隔热性好、与基底附着力强、力学性能优异、耐烧蚀、耐高温、易于施工等特点。

Upconversion luminescence and temperature sensing performance of Er^(3+) ions doped self-activated KYb(MoO_(4))_(2) phosphors

In this work,a series of self-activated KYb(MoO_(4))_(2) phosphors with various x at% Er^(3+) doping concentrations(x=0.5,1,3,5,8,10,15) was synthesized by the solid-state reaction method.The phase structure of the as-prepared samples was analyzed by X-ray diffraction(XRD),XRD Rietveld refinement and Fourier transform infrared(FT-IR) spectroscopy.The as-prepared samples retain the orthorhombic structure with space group of Pbcn even Er^(3+) doping concentration up to 15 at%.High-purity upconversion(UC) green emission with green to red intensity ratio of 55 is observed from the as-prepared samples upon the excitation of 980 nm semiconductor laser and the optimum doping concentration of Er^(3+) ions in the self-activated KYb(MoO_(4))_(2) host is revealed as 3 at%.The strong green UC emission is confirmed as a two-photon process based on the power-dependent UC spectra.In addition,the fluorescence intensity ratios(FIRs) of the two thermally-coupled energy levels,namely ^(2)H_(11/2) and ^(4)S_(3/2).of Er^(3+) ions were investigated in the temperature region 300-570 K to evaluate the optical temperature sensor behavior of the sample.The maximum relative sensitivity(S_(R)) is determined to be 0.0069 K^(-1) at300 K and the absolute sensitivity(S_(A)) is determined to be 0.0126 K^(-1) at 300 K.The S_(A) of self-activated KYb(MoO_(4))2:Er^(3+)is almost twice that of traditional KY(MoO_(4))2:Er^(3+)/Yb^(3+)codoping phosphor.The results demonstrate that Er^(3+) ions doped self-activated KYb(MoO_(4))2 phosphor has promising application in visible display,trademark security and optical temperature sensors.

室温固相反应助力制备氮硫共掺杂碳限域的FeCoS_(2)复合物用于高性能钠离子电池负极

利用室温固相自组装反应制备Co和Fe双席夫碱配合物,随后在硫粉存在下中温热处理,使该配合物同时发生热解碳化和固相硫化反应,从而获得N、S共掺杂碳限域的FeCoS_(2)纳米复合物(记为FeCoS_(2)■NSC)。通过粉末X射线衍射、透射电镜、X射线光电子能谱和热重分析技术分别对纳米复合物的物相、形貌结构、组分和含量等进行物理表征,并通过循环伏安、恒电流充放电技术测试其电化学储钠性能。研究结果表明,最优化条件下制备的复合物(FeCoS_(2)■NSC-7001)中FeCoS_(2)粒子的平均尺寸约为3.4 nm,且被均匀限域在N、S共掺杂的碳基体中;该复合物作为钠离子电池负极时,在0.1 A·g^(-1)的电流密度下经过300次充放电循环,其可逆充电比容量仍高达310.4 mAh·g^(-1);即使在5 A·g^(-1)的大电流密度下,其充电比容量也高达146.0 mAh·g^(-1),呈现优异的电化学储钠性能。

室温自交联环氧酯树脂的制备及性能研究

通过不饱和脂肪酸与环氧分子链上的环氧基和羟基进行酯化反应,制备出不同酯化程度的室温自交联环氧酯。研究了油酸种类、油度、反应温度、反应时间、松香树脂添加量对环氧酯树脂性能的影响。结果表明:当亚油酸与桐油酸的质量比为2∶1、松香树脂的添加量为5%,油度为70%时,制备出的环氧酯树脂干燥性能、硬度等性能最佳;当酯化反应温度为200℃、反应时间为7 h时,环氧酯树脂的合成工艺较为稳定,且制备的环氧酯底漆具有优异的干燥性能、硬度及耐水性能,适用于桥梁、管道、储罐、汽车等设施中钢铁构件的防护,应用前景广阔。

A new room temperature viscoelastic inorganic glass

Inorganic glass is a non-crystalline material that lacks of a regular,periodic atomic or molecular structure,and are considered as frozen liquids because of the similarity between their static amorphous structures.The atoms and molecules in the glass can gradually rearrange and realign with time,giving rise to deformation or aging in most glass materials.However,viscoelastic behavior could not be readily observable at room temperature(RT)due to its long time scale.The paper introduce and comment a recent work published in Nature Energy,which discover a new class of viscoelastic inorganic glass with Tg well below RT.The VIGLAS is simply synthesized through adding high content of oxygen into tetrachloroaluminates to replace chlorine.The VIGLAS exhibits characteristics similar to both inorganic ceramics and organic polymers,which are particularly relevant in the realm of battery electrolytes where a balance between ionic conductivity and chemo-mechanical compatibility is crucial.

Green synthesis of NiFe LDH/Ni foam at room temperature for highly efficient electrocatalytic oxygen evolution reaction

Clean energy technologies such as water splitting and fuel cells have been intensively pursued in the last decade for their free pollution. However, there is plenty of fossil energy consumed in the preparation of the catalysts,which results in a heavy pollution. Therefore, it is much desired but challenging to fabricate high-efficiency catalysts without extra energy input. Herein, we used a facile one-pot room-temperature method to synthesize a highly efficient electrocatalyst of nickel iron layered double hydroxide grown on Ni foam(NiFe LDH/NF) for oxygen evolution reaction(OER). The formation of the NiFe LDH follows a dissolutionprecipitation process, in which the acid conditions by hydrolysis of Fe^3+ combined with NO3^- could etch the NF to form Ni^2+. Then, the obtained Ni^2+ was co-precipitated with the hydrolysed Fe^3+ to in situ generate NiFe LDH on the NF. The NiFe LDH/NF exhibits excellent OER performance with a low potential of about 1.411 V vs. reversible hydrogen electrode(RHE) at a current density of 10 m A cm^-2, a small Tafel slope of 42.3 mV dec^-1 and a significantly low potential of ~1.452 V vs. RHE at 100 mA cm^-2 in 1 mol L^-1 KOH. Moreover, the material also keeps its original morphology and structure over 20 h. This energy-efficient strategy to synthesize NiFe LDH is highly promising for widespread application in OER catalyst industry.

Room-Temperature Suzuki-Miyaura Reaction Catalyzed by Palladium Nanoparticles in Lactate-Anion Ionic Liquid

A palladium nanoparticle catalyst(PdNPs@[Bmim]Lac)has been prepared by a simple,mild and efficient chemical approach using 1-butyl-3-methylimidazolium lactate([Bmim]Lac)ionic liquid)as a stabilizer.This catalyst exhibits excellent activity,stability,recyclability and simple manipulation in Suzuki-Miyaura reactions at room temperature in air.

Synthesis of trans-bis(glycin- ato) copper(II) complex nanorods by room tempera- ture solid-state reaction

Trans-[Cu(glyo)2(H2O)] nanoparticles with average diameters about 20—30 nm were prepared by one- step room temperature solid-state reaction. Trans-[Cu(glyo)2] nanorods with diameters ranging from 100 to 150 nm and lengths up to several ìm were also prepared by one-step room temperature solid-state reaction in the presence of a suitable nonionic surfactant PEG400. The chemical composi- tion and structural features of the products were investigated by elemental analyses, XRD, TG, SEM and TEM, respec- tively. The mechanisms of formation were also discussed.

Synthesis of polysubstituted pyrroles via a gold(Ⅰ)-catalyzed tandem three-component reaction at room temperature

A gold(Ⅰ)-catalyzed three-component reaction of β-nitrostyrenes with 1,3-dicarbonyl compounds and primary amines to form polysubstituted pyrroles has been developed at room temperature in ethanol.The key advantages of the three-component reaction are the mild reaction conditions and environmentally safer solvent.

Low temperature solid-state synthesis and characterization of uniform YF_3 submicroparticles

In this paper, submicro-scaled YF3 particles with uniform rice-like morphologies were facilely synthesized by reacting yttrium nitrate with tetrabutylammonium fluoride via a solid-state reaction process at 50 °C for 12 h.The phase confirmation and morphology of the as-prepared YF3 particles were investigated by X-ray powder diffraction（XRD） and scanning electron microscopy（SEM）.SEM results reveal that the YF3 submicroparticles are about 700 nm in length and 260 nm in width. Eu^3＋ and Tb^3＋ doped YF3 submicroparticles were also prepared with similar process and their photoluminescence properties were studied. Results demonstrate that the doping of Eu^3＋ and Tb^3＋ has slight effect on the morphologies of the product. Owing to the small average crystallite size or the low crystallinity of the product, the photoluminescence intensity of the Eu^3＋ and Tb^3＋ doped YF3 submicroparticles is very weak. Some characteristic peaks even cannot be observed in the emission spectrum.