以NH4HCO3为沉淀剂通过共沉淀法制备2Y-TZP纳米粉体

以NH_4HCO_3,ZrOCl_2·9H_2O和Y(NO_3)_3为原料,在乙醇溶液中通过共沉淀法制备2Y-TZP纳米粉体,并对其中的反应机理进行研究.在沉淀过程中,NH_4HCO_3和ZrOCl_2通过两步反应生成(NH_4)_3ZrOH(CO_3)_3·2H_2O对沉淀.首先NH_4HCO_3和ZrOCl_2反应生成Zr(OH)_4,其后Zr(OH)_4和NH_4HCO_3进一步反应生成(NH_4)_3ZrOH(CO_3)_3·2H_2O.(NH_4)_3ZrOH(CO_3)_3·2H_2O不稳定,在130℃即可分解生成ZrO_2,并放出氨气、水和二氧化碳.沉淀产物经300和450℃煅烧后得到的ZY-TZP粉体颗粒尺寸细小,不存在大的硬团聚,具有良好的烧结性,在1225℃即可实现高度致密化.     

氧、氮、乙炔及碱液的分析

氧气分析系采用汉浦氏仪器测定;氧在仪器中与放在氯化铵和氢氧化铵溶液中的铜丝圈起化合作用,其化学反应如下。 2CU+O_2→2CUO CuO+2NH_4Cl+H_2O→2NH_4OH+CuCl_2 CuCl_2+2NH_4OH→Cu(OH)_2+2NH_4Cl Cu(OH)_2+4NH_4OH→Cu(NH_3)_4(OH)_2+4H_2O     

单分散γ-Al_2O_3纳米颗粒制备工艺参数的调控

采用均相沉淀法,在950℃煅烧碱式硫酸铝(Al(SO_4)_x(OH)_y)纳米颗粒2h,制备出单分散的γ-Al_2O_3纳米颗粒。研究了阴离子、浓度和沉淀剂/铝盐摩尔比对Al(SO_4)_x(OH)_y颗粒的形貌、尺寸和分散性的影响。结果表明,Al(SO_4)_x(OH)_y颗粒的最佳制备条件为:二甲胺硼烷(DMAB)作沉淀剂、Al_2(SO_4)_3.18H_2O作铝源、[Al~(3+)]=0.0005mol/L、n(DMAB)/n(Al_2(SO_4)_3·18H_2O)=40。制备出的Al(SO_4)_x(OH)_y具有球形、平均颗粒尺寸为98nm、粒径分布为75~130nm、单分散性的特点;获得了球形、平均颗粒尺寸为90nm、粒径分布范围为50~105nm、单分散的γ-Al_2O_3颗粒。     

Li_2O-Al_2O_3-WO_3三元系中Al_2(WO_4)_3-Li_2WO_4和Al_2(WO_4)_3-Li_2O截面的相平衡研究

本文用 X 射线衍射和差热分析等方法研究了 Li_2O-Al_2O_3-WO_3三元系中 Al_2(WO_4)_3-Li_2WO_4和 Al_2(WO_4)_3-Li_2O 截面相平衡关系。在 Al_2(WO_4)_3-Li_2WO_4赝二元系中生成一新化合物 Al_2(WO_4)_3·Li_2WO_4,该化合物在883±3℃由包晶反应生成。它与 Li_2WO_4形成共晶体系,共晶温度为680±3℃,共晶点组成为90mol%Li_2WO_4。在 Al_2(WO_4)_3-Li_2O 截面中由包晶反应形成一新化合物 Al_2(WO_4)_3·4Li_2O,其包晶反应温度为720±3℃。在这一截面中,在组份45mol%Li_2O 处存在一化合物,该化合物确定为 Al_2(WO_4)_3·Li_2WO_4。Al_2(WO_4)3·4Li_2O 与 Al_2(WO_4)_3·Li_2WO_4形成共晶体系,其共晶温度为682±3℃,共晶点组成约为70mol%Li_2O。     

化学沉淀法合成氧化锰纳米粉体

以乙酸锰(Mn(Ac)_2·4H_2O)、双氧水(H_2O_2)及氨水(NH_3·H_2O)为原料,通过水浴化学沉淀直接合成Mn_3O_4纳米粉体。采用XRD和SEM对样品成分和形貌进行表征,发现水浴温度80℃、原料物质的量比为1∶2∶2时合成的样品结晶完善,形状规则,尺寸均匀。双氧水用量较少时有异形结构生成;氨水不足会造成产物大小不均匀;水浴温度过高或过低都会造成产物形状不规则,粒径分布变宽。TG/DTA结果显示,样品在空气中升温时存在3次转变,分别在202℃、338℃附近生成了相似结构的Mn_3O_4,仅晶格尺寸发生变化;超过455℃生成了立方方铁锰矿的α-Mn_2O_3。对比产物在不同温度下煅烧后的XRD图谱和TEM照片,发现600℃煅烧生成的α-Mn_2O_3结晶完善,团聚较少,晶格尺寸(a=b=c=9.412?)接近标准值。     

化学沉积镍硼镀层

西德拜耳染料制造公司(FarbenfabrikBayer A G)推荐含有硼氢酸钠 NaBH_4或胺类的添加物和氢化硼(BH_3)形成的化学镀镍槽液。沉积物含有91～93％的镍,6.8～7.1％的硼;镀层硬度为维氏500～750度,经在400℃处理1/2～1小时,硬度可     

NH2-UIO-66负载RuCuMo纳米催化剂的制备及其催化产氢

采用锆盐和2-氨基对苯二甲酸以溶剂热法成功制备了氨基化的金属有机骨架化合物NH₂-UIO-66, 并利用浸渍还原法成功负载RuCuMo纳米粒子, 制备了RuCuMo@NH₂-UIO-66催化剂。通过X射线粉末衍射仪(XRD)、透射电子显微镜(TEM)、场发射扫描电镜(SEM)等技术对NH₂-UIO-66、RuCuMo@NH₂-UIO-66的结构、形貌、组成和比表面积进行了表征, 并对载体、多金属负载型催化剂以及无载体的RuCuMo纳米粒子的产氢性能进行了分析。结果显示, Ru₁Cu₂Mo_0.5@NH₂-UIO-66催化剂的催化活性最高, 引入Cu和Mo能显著增强Ru对氨硼烷水解产氢的催化活性。这主要归因于RuCuMo纳米粒子之间强的协同作用, RuCuMo纳米粒子与载体NH₂-UIO-66间的双功能效应, 以及MOFs上氨基的锚锭作用, 可以阻止金属粒子的团聚, 促进超细粒子的形成。催化反应的活化能(E_a)为30.1 kJ?mol ^-1, 转化频率(TOF)为180.83 $\text{mo}{{\text{l}}_{{{\text{H}}_{2}}}}\cdot \text{mol}_{\text{Ru}}^{-1}\cdot {{\min }^{-1}}$, 非贵金属Cu和Mo的引入为催化活性的提高和工业应用提供了重要的研究价值。     

一种用于吸附HF气体中微量水分的CaF_2材料及其制备方法

正申请(专利)号:201910353568.4公开(公告)日:2019-07-23申请(专利权)人:浙江师范大学摘要:本发明涉及一种用于吸附HF气体中微量水分的CaF_2材料及其制备方法,以Na_3C_6H_5O7·2H_2O为络合剂,Ca(CH_3COO)_2为钙源,NaBF_4为氟源,通过水热法合成CaF_2材料,Ca(CH_3COO)_2、Na_3C_6H_5O_7·2H2_O、Na BF_4的摩尔比为1∶5∶2。用该     

HCVD法生长InN纳米棒的可控制备及表征

实验通过自制的卤化物化学气相沉积(HCVD)装置在Si(111)衬底上实现了InN纳米棒的可控生长。系统研究了InCl_3源区温度、NH_3流量和N_2载气流量对InN纳米棒生长的影响,并利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和X射线能谱仪(EDS)对样品结构,形貌和元素组成进行了表征。结果表明,InCl_3源区温度的升高,有利于提高生长区InN纳米棒的形核率和生长速率;NH_3流量大小对InN纳米棒晶体质量有重要影响,适量NH_3流量会满足In源生长需要的Ⅴ/Ⅲ比,改善纳米棒晶体质量,当NH_3流量过大时,In空位缺陷的形成会使晶体质量变差;N_2载气流量大小会影响In源和N源的浓度和偏压,从而能有效调控InN纳米棒直径和生长速率。研究实现了InN纳米棒的可控生长,为开发高性能InN纳米棒器件奠定了基础。     

沉淀法制备氟磷灰石纳米粉体

氟磷灰石由于具有良好的生物相容性和优异的化学稳定性而得到越来越多的应用,对其制备方法的研究显得十分重要。分别以Ca(NO_3)_2·4H_2O、(NH_4)_2HPO_4、NH_4F为Ca源、P源、F源,采用沉淀法制备氟磷灰石纳米粉体。借助X射线衍射(XRD)、场发射扫描电镜(FESEM)和透射电镜(TEM)对反应产物进行表征,研究反应物浓度、热处理温度、合成环境的pH值对氟磷灰石形貌的影响。结果表明,随着制备环境条件的变化,氟磷灰石产物的尺寸和长径比差异较大,长度为30~200nm,直径为10~50nm,长径比为3~10,并依据晶体生长理论探索了不同制备条件对氟磷灰石形貌的影响机理。     

铜包裹碳化硅颗粒复合粉体的化学原位沉积制备与表征

以铜氨离子为铜源, 水合肼为还原剂, 在表面预氧化的SiC表面, 采用一步原位化学沉积法制备了均匀包裹Cu颗粒的SiC复合粉体. 采用扫描电子显微镜(SEM)、X射线衍射(XRD)、傅立叶红外光谱(FT-IR)、Zeta电位等测试表征手段研究了工艺条件对原位沉积反应的影响. 研究发现SiC表面预氧化形成的SiO2层能显著增强对铜氨离子吸附能力, 有助于原位还原生成单质Cu, 形成近乎连续包裹层. 控制反应体系中铜氨离子浓度和反应温度可以影响反应速率, 从而控制Cu颗粒的沉积速率和包裹效果. 对比研究表明, 在0.2 mol/L铜氨离子溶液中70℃反应, 在预氧化的SiC表面能够获得最佳包裹层.     

NH_3BH_3/NaH复合物及其水解特性

以NaH为诱导剂,通过高能球磨工艺制备NH3BH3和NaH的复合物,分析研究了复合物的物相、颗粒形态及其水解性能。结果表明在球磨过程中NH3BH3和NaH反应生成NaBH4新相,但反应并不完全,复合物中的NH3BH3包覆在NaH和生成的NaBH4颗粒表面并发生部分非晶化。诱导剂NaH的加入能有效地改善NH3BH3的水解放氢性能。当NH3BH3/NaH为2.5：1,60℃下,0.1g该复合物10min内放出125mL的H2,约为10.2%（质量分数）,其中一半来源于H2O。     

B4C与NH4Cl生成BN反应的研究

研究了Ｂ４Ｃ,ＮＨ４Ｃl和Ｌi3N在不同条件下的反应,分析了Ｌi3Ｎ及Ｈ２,Ｎ２,ＮＨ３等气体在上述反应中的作用,结果表明,在Ｎ２气氛及１２２３Ｋ温度下,Ｂ４Ｃ与Ｌi3N反应生成hBN,B4C与ＮＨ４Ｃl反应只生成少量hBN,而Ｂ４Ｃ,ＮＨ４Ｃl,Li3N共同反应有大量hBN生成,说明在高温高压下合成cBN的常催化剂Li3N,在常压高温下Ｂ４Ｃ与ＮＨ４Ｃl生成hBN的反应中也起催化作用。     

尼龙-6膜与丙烯酸接枝共聚合的研究

通过一系列实验选择以（NH4）2（NO）6／HSO4为引发剂,了尼龙－6膜与丙烯酸的接枝共聚合反应,通过改变单体浓度,反应温度,（NH4）2Ce(NO3)6浓度,H2SO4浓度,尼龙－6膜在甲酸中的溶胀时间等因素发现,接枝膜的接枝率与单体浓度有关,。随单体浓度的改变,接枝率有一个极大值,单体浓度高于或低于此浓度,接枝率都较低,通过改变（NH4）2Ce(NO3)6和H2SO4浓度也得到类似规律,反应温度对接枝膜的接枝率也有影响,温度过高（＞70度）或过低（小于40℃）都得不到较高的接枝率;将尼龙－6膜在20％甲酸中溶胀,有利于提高产物的接枝率。     

二钼酸铵的热分解行为研究

采用DTA、TG和XRD等检测手段研究了二钼酸铵的热分解行为,结果表明：二钼酸铵的热分解经历了两个阶段,所对应的反应温度分别在180℃左右及300℃左右,二钼酸铵热分解反应第一步为：4（NH4）2MO2O7→180℃ （NH4）4MO8O26＋4NH3↑＋2H2O↑;第二步为（NH4）4MO8O26→300℃ 8MoO3＋4NH3↑＋2H2O↑。     

A study on major inorganic ion composition of atmospheric aerosols at Tirupati

Atmospheric aerosol samples were collected from an urbanized area (Tirupati, South India) during the period April to September 2001 and were analyzed for major inorganic ions-F, Cl, NO(3,) SO(4), Na, K, Mg, Ca and NH(4) by employing the ion chromatograph. The average mass of the aerosol was found to be 55.64 microgram(-3) with a total water-soluble load (total anion+total cation) of 5.74 microgram(-3). Seasonal distribution of the aerosol mass and temporal variations of the ion concentrations present a clear trend of lowering atmospheric levels during the rainy season due to washout effect. Composition of the aerosols showed higher concentration of SO(4) followed by NO(3) and NH(4) and found to be influenced by local terrestrial sources. The presence of SO(4) and NO(3) may be due to re-suspension of soil particles (formation by heterogeneous oxidation). Ca, Mg and Cl are mainly soil derived ones. The presence of NH(4) may be attributed to the reaction of NH(3) vapors with acidic gases such as H(2)SO(4), HNO(3) and HCl or ammonia vapor may react or condense on an acidic particle surface of anthropogenic origin. Equivalent ratios of NH(4)/(NO(3)+SO(4)) varied between 0.62 and 0.74. It shows the aerosol to be slightly acidic due to the neutralization of basicity by SO(2) and NO(x).     

Phosphogypsum Utilization Part II: Preparation of Ammonium Sulphate

The aim of this work was to describe the conversion of raw phosphogypsum, issued from the manufacture of H3PO4 by dissolving the phosphate rock in H2SO4, into (NH4)2SO4 and CaCO3. The thermal analysis technique was used to estimate the yield of conversion. (NH4)2CO3 or (NH4)2CO3 with excess NH4OH or (NH4)2CO3 with NH3 gas were used in the preparation of (NH4)2SO4 from phosphogypsum. The obtained samples were separated and tested by chemical and thermogravimetric analyses, infrared spectrum and X-ray diffraction and the optimum conditions of conversion were determined. The results indicated that the yield of conversion equals to 83.37 and 86.70% in case of using (NH4)2CO3 or (NH4)2CO3 with excess ammonia respectively, while by using NH3 gas the percentage of conversion increased to 94.2% at a flow rate of 6 ml/min. Chemical analysis, infrared spectrum and X-ray diffraction patterns of the yield, (NH4)2SO4 were nearly similar to the standard sample.     

One step method of structure engineering porous graphitic carbon nitride for efficient visible-light photocatalytic reduction of Cr(Ⅵ)

Porous g-C3N4 nanosheets (PCN) were prepared by the nickel-assisted one-step thermal polymerization method.Hydrogen (H2) which was produced by the reaction between nickel (Ni) foam and ammonia (NH3) defined the structure and properties of PCN.During the formation of PCN,the participation of H2 not only enhanced the spacing between layers but also boosted the specific surface area that more active sites were exposed.Additionally,H2 promoted pores formation in the nanosheets,which was beneficial to the transfer of photons through lamellar structure and improved the absorption efficiency of visible light.Remarkably,the obtained PCN possessed better Cr(Ⅵ) photocatalytic reduction efficiency than pure g-C3N4.The reaction rate constant (k) of PCN (0.013 min-1) was approximately twice that of bare g-C3N4 (0.007 min-1).Furthermore,the effects of original pH and concentration of Cr(Ⅵ)-containing solution on removal efficiency of Cr(Ⅵ) were explored.A possible photocatalytic mechanism was proposed based on the experiments of radical scavengers and photoelectrochemical characterizations.     

2种碱化剂对压水堆二回路结构材料腐蚀行为的影响

为考察碱化剂抑制压水堆二回路结构材料腐蚀的情况,通过腐蚀失重法、电化学极化曲线、扫描电镜(SEM)以及小角XRD分析等方法研究了模拟压水堆二回路水化学环境中分别添加乙醇胺(ETA)和氨水(NH_3·H_2O)_2种碱化剂对A508Ⅲ钢和P22钢2种结构材料的腐蚀行为的影响。结果表明:2种结构材料腐蚀速率均在10~(-1)~10~(-2)mg/(dm~2·h)之间,但在ETA中腐蚀电流密度更小,腐蚀速率也更低。在2种结构材料表面形成的主要腐蚀产物均为Fe_3O_4,SEM观察到在ETA中生成的腐蚀产物较为致密。比较ETA与NH_3·H_2O的物化性能,可知在高温水(280℃)中ETA的挥发性能弱于NH_3·H_2O,因此添加ETA的溶液的pH值更高,pH值的不同决定了2种材料的溶液腐蚀行为的差异。综上所述,二回路结构材料在ETA环境中的耐蚀性能更好。     

A photothermal interferometer for gas-phase ammonia detection

Detection of gas-phase ammonia is particularly challenging because ambient ammonia concentrations may be less than 1 ppb (molecules of NH(3) per 10(9) molecules of air), ammonia sticks to many materials commonly used to sample air, and particles containing ammonium may interfere with gas-phase measurements. We have built a new and sensitive photothermal interferometer to detect gas-phase ammonia in situ, under typical atmospheric conditions. Ammonia molecules in sampled air absorb infrared radiation from a CO(2) laser at 9.22 μm, with consequent collisional heating, expansion, and refractive index change. This change in refractive index is detected as a phase shift in one arm of a homodyne interferometer. Measurements of vibrational and electrical noise in the interferometer correlate to an instrumental lower limit of detection of 6.6 ppt ammonia in 1 s. The CO(2) laser output is modulated at 1.2 kHz, and the ac signal from the interferometer is measured with a lock-in amplifier. The detector is zeroed by sampling through a H(3)PO(4)-coated denuder tube and is calibrated by dynamic dilution of two permeation tube outputs and by standard addition. Signal gain is insensitive to CO(2) or H(2)O in the sample, and the signal is linear over 5 orders of magnitude. The instrument 2σ precision is 31 ppt when the signal is integrated for 100 s and 250 ppt with a 1-s integration time. The windowless sample cell and inlet is fabricated entirely of glass to minimize sample loss and hysteresis. The instrument response time is demonstrated to be about 1 s.