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.

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.

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。

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.

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。

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 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.

Visible light induced tandem reactions:An efficient one pot strategy for constructing quinazolinones using in-situ formed aldehydes under photocatalyst-free and room-temperature conditions

A facile tandem route has been developed for constructing quinazolinones from various aminobenzamides and in-situ generated aldehydes.Visible light was found to play a dual role:first oxidizes the alcohol to the aldehyde and then facilitates its cyclization with o-substituted aniline.Furthermore,alcohols are perfe ct alternatives to aldehydes because they are greene r,more available,more economical,more stable,and less toxic tha n aldehydes.The first reaction step continuously provides material for the second step,which effectively reduces loss through volatilization,oxidation,and polymerization of the aldehyde,while avoiding its toxicity.A variety of quinazolinones can be prepared in the presence of visible light without any additional photocatalyst.The developed synthesis protocol proceeds with the merits of mild conditions,broad substrate scope,operational simplicity,a nd high atom efficiency,with an eco-energy source under metal-free,photocatalyst-free,and ambient conditions.

室温固相法制备硼化铁及电催化分解水产氢性能

采用室温固相反应和煅烧后处理相结合的方法,成功合成了高活性的硼化铁析氢催化剂。通过扫描电子显微镜(SEM)、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)、电感耦合等离子发射光谱仪(ICP)等技术表征了硼化铁催化剂的组成、结构和形貌。和传统的溶液法制备的硼化铁相比,室温固相法制备出的硼化铁表现出更加优异的析氢性能,在碱性电解质溶液中,在100 mA·cm^(-2)的电流密度下,固相法制备的硼化铁的HER过电位为303 mV,塔菲尔斜率为65 mV·dec^(-1),分别低于溶液法制备的硼化铁的402 mV和80 mV·dec^(-1)。其原因是固相法制备的硼化铁含有比溶液法制备的硼化铁更高的硼含量、更好的导电性。室温固相法制备硼化铁消耗的硼氢化钠要远小于溶液法,且大大减少废水排放,有利于降低制备成本和环境保护,有良好的应用前景。

室温固相法制备纳米氧化铋

以NaOH和Bi(NO_3)_3·5H_2O为原料,并添加不同的分散剂,采用室温固相法制备了纳米Bi_2O_3采用XRD、TEM表征纳米Bi_2O_3的结构和形貌。结果表明,分散剂种类、分散剂的添加量等因素显著影响纳米Bi_2O_3结构和形貌。

ZnSnO_3纳米粉体的合成及其气敏特性研究

在遵守热力学限制的前提下 ,以无机盐ZnSO4 ·7H2 O ,SnCl4 ·5H2 O ,NaOH为原料 ,在室温条件下 ,对反应物进行研磨 ,TG -DTA曲线表明 ,在研磨过程中 ,混合物发生反应生成ZnSn(OH) 6 ,60 0℃热处理 1h后得到钙钛矿型复合氧化物ZnSnO3,X射线粉末衍射 (XRD)、透射电镜 (TEM )等表征结果表明 ,产物为均相ZnSnO3,平均粒径约为 3 0nm左右 ;将样品制成烧结型气敏元件 ,对C2 H5OH有较高的灵敏度和选择性 ,工作温度为 2 40℃时 ,对酒精的灵敏度高达 19.7,响应 -恢复时间分别仅需 7s和 10s.

室温固相反应法制备CeO_2纳米晶

采用室温固相反应法制备了CeO_2纳米晶。XRD分析表明,所合成的CeO_2纳米晶属于立方晶系。TEM分析表明,CeO_2纳米粒子呈球形,粒度随焙烧温度的增加而增大。热失重分析表明,样品的热失重主要受温度的影响,而焙烧时间的影响不大。相对密度分析表明,随CeO_2纳米晶粒度的增大,粉末的密度略有增加。

室温固相合成纳米ZnS及其气敏性能研究

以无机盐ZnSO4·7H2O和Na2S·9H2O为原料,用室温固相化学反应合成了ZnS;用XRD、TEM对产物的组成、大小、形貌进行了表征;用TG-DTA确定了ZnS的稳定温区.结果表明,产物为纳米颗粒,平均粒径为15nm左右,且610℃以下能在空气中稳定存在.另外还采用静态配气法测定了材料的气敏性能,发现ZnS对H2S有很高的灵敏度,且抗干扰能力强,有很好的应用前景.