BaO-B2O3-GeO2(BaO≤50 mo1%)三元系相图的研究
梁敬魁, 柴璋, 张金平
【物理化学学报】doi: 10.3866/PKU.WHXB19870512
本文用X射线衍射及差热分析等方法, 研究了BaO-B_2O_3-GeO_2(BaO≤50 mol%)三元系的室温截面相图。发现了一个新的三元化合物Ba_3B_6Ge_2O_(16)(3BaO·3B_2O_3·2GeO_2)。并且研究了BaB_2O_4-Ba_3B_6Ge_2O_(16), BaGeO_3-Ba_3B_6Ge_2O_(16), BaB_2O_4-BaGeO_3三个二元系相图。它们都是共晶体系, 共晶温度分别为937±3 ℃、879±3 ℃875±3 ℃; 共晶组分分别为(BaO)_(0.42)(B_2O_3)_(0.42)(GeO_2)_(0.16), (BaO)_(0.42)(B_2O_3)_(0.24)(GeO_2)_(0.34), (BaO)_(0.50)(B_2O_3)_(0.27)(GeO_2)_(0.23)。这三个二元系组成一个三元共晶体系, 其三元共晶温度为870±3 ℃, 共晶组分为(BaO)_(0.46)(B_2O_3)_(0.27)(GeO_2)_(0.27)。
CuO-BaO/SiO2催化剂的结构表征
杨儒, 胡天斗, 刘涛, 相宏伟, 钟炳, 徐耀, 吴东
【物理化学学报】doi: 10.3866/PKU.WHXB19980704

 以XRD、XPS和EXAFS手段对CuO-BaO/SiC2催化剂及其还原态的结构进行了研究.结果表明,在CuO-BaO/SiO2体系中铜和钡都是以氧化态的形式存在,超细SiO2载体对所负载的CuO的结构有影响.随着样品负载量的逐渐降低,Cu-O和Cu-Cu键的键长和配位数逐渐减小,而且低载量样品的键长和配位数减小的幅度最大.在总负载量>13.39%的样品中,CuO以晶相的形式存在;总负载量≤13.39%的样品中,CUO呈现单层分布的高分出状态.还原态样品中钢以本价铜的形式存在,随负载量的降低,还原态Cu-Cu键的键长和配位数也分别呈现出逐渐减小的趋势.还原态中心铜原子在催化剂表面的分布状态基本上保持了氧化态催化剂中CuO物相的分布状态.

关键词:

氧化铜, 氧化钡, 超细二氧化硅, XRD, XPS, EXAFS

Eu3+激活的SrO-BaO-SiO2发光材料的合成和特性研究
李彬, 白玉白, 王雅茹, 张洪非, 关实之, 赵永年, 张瑛琳
(Sr,Ba)SiO3:Eu3+是以SrCO3、BaCO3、H2SiO3、Li2CO3、Eu2(C2O4)3为原料,经高温烧结而成。合成发光材料过程中,用正交试验法进行实验条件的探索。得到了发光材料的最佳组成为:(Sr0.8Ba0.2)0.95Eu0.025Li0.025SiO3或Si0.95Eu0.025Li0.025SiO3。最佳实验条件为:灼烧温度1150℃,灼烧时间3小时。通过X-射线粉末衍射谱、激光荧光光谱、发光光谱和激发光谱研究了发光材料的结构和发光特性。
整体式担载型Pt基催化剂上航空煤油的裂解:助剂SrO和BaO的影响
焦毅, 王佳, 秦莉晓, 王健礼, 朱权, 李象远, 龚茂初, 陈耀强
【催化学报】doi: 10.1016/S1872-2067(12)60541-5
考察了整体式担载型Pt基催化剂上国产3号航空煤油(RP-3)的常压裂解反应,着重探讨了添加BaO和SrO助剂对裂解效果的影响,以及裂解时间对积炭量的影响.采用全自动吸附仪、程序升温还原、X射线光电子能谱以及X射线衍射和扫描电镜等方法对催化剂进行了表征.结果表明,在整体式担载型Pt基催化剂上RP-3裂解的总产气量比热裂解提高了39.7%;BaO或SrO助剂的添加又使其总产气量又分别提高了25.6%和37.0%;同时添加BaO和SrO的催化剂,其催化裂解总产气量则提高了96.5%.BaO和SrO助剂均可有效地抑制积炭的生成,而两者间的协同作用,进一步抑制了RP-3催化裂解过程中积炭的生成.
关键词: 催化裂解, 积炭, 碱土金属氧化物, 吸热燃料, 整体式催化剂
CaO或BaO与Sm2O3共掺杂CeO2体系电子结构和氧离子迁移的DFT+U研究
吴铜伟, 贾桂霄, 包金小, 刘媛媛, 安胜利
【无机化学学报】doi: 10.11862/CJIC.2016.172
使用GGA+U方法研究了CaO或BaO与Sm2O3共掺杂CeO2体系几何和电子结构及氧离子迁移。计算结果表明,Ba和Sm均靠近氧空位时BaSmCe30O63体系最稳定;Sm靠近,Ca远离氧空位时CaSmCe30O63体系最稳定。BaSmCe30O63和CaSmCe30O63体系中均不存在Ce4+变价。对CaSmCe30O63体系氧离子迁移的研究发现,当氧离子迁移到空位时,迁移能大小顺序为Em(3→V) < Em(1→V) < Em(4→V) < Em(2→V),这一规律源于氧离子与低价掺杂离子产生负电势之间的排斥作用;对BaSmCe30O63体系氧离子迁移的研究发现,当空位迁移到周围氧离子时,迁移能大小顺序为Em(V→3) < Em(V→5) < Em(V→1),这一规律源于氧空位产生的正电势与低价掺杂离子产生的负电势之间的吸引作用。此外,CaSmCe30O63体系最小迁移能小于SmCe31O63体系,证实了CeO2-Sm2O3-CaO体系离子电导率大于CeO2-Sm2O3体系的实验结果。
关键词: 二氧化铈, 掺杂, 电子结构, 氧离子迁移, 第一性原理
浸渍/共沉淀法对BaO改性单Pd催化剂净化甲醇汽油车尾气性能的影响
张雪乔, 田浩杞, 叶芝祥, 陈耀强
【无机化学学报】doi: 10.11862/CJIC.2015.002
采用浸渍和共沉淀两种方法分别制备了BaO改性的Pd/CeO2-ZrO2-La2O3-Al2O3催化剂.运用N2吸附-脱附,X射线衍射(XRD),H2程序升温还原(H2-TPR),NH3程序升温脱附(NH3-TPD),透射电子显微镜(TEM)和X射线光电子能谱(XPS)对催化剂进行表征,并考察其对甲醇,CO,C3H8和NO的催化性能.活性测试结果表明,BaO的引入可明显改善Pd催化剂对甲醇,CO,C3H8和NO的催化活性,且浸渍法最佳,起燃温度(T50)分别降低了43,31,45和35℃.XRD,H2-TPR及XPS结果表明,浸渍法引入BaO主要通过表面改性方式,强化Pd-Ce界面间的相互作用,改善催化剂的还原性能,进而提高催化剂的低温活性;而共沉淀法则是通过结构改性方式增加CeO2晶格缺陷,加速活性氧物种的流动,Ce3+浓度的增加是促使CO氧化活性显著提高的主要原因.
关键词: 氧化钡;钯;铈;甲醇;催化转化
化学发光反应Ba+N2O产物BaO的传能和Ba+O2+M的机理
梁寅春
Ba/N2O反应曾被认为是有可能发展电子跃迁化学激光的反应体系。在热管炉反应器中作了Ba/N2O化学发光反应,记录了产物BaO(A'∑+→X1+)的化学发光光谱。光谱的特点及压力相关性,表明BaOA1+不是化学反应产物的先驱态、它的布居是可能的先驱态(b3π和A'1π)经碰撞转移到A1+态实现的。
Preparation of BaO·4B2O3·5H2O Nanomaterial and Evaluation of Its Flame Retardant Performance to PP by Thermal Decomposition Kinetics Method
Jing Miao, Ruifeng Guo, Zhihong Liu
【物理化学学报】doi: 10.3866/PKU.WHXB201905052
Borate is considered one of the most important additives for improving the fire-resistance of combustible polymers because of its smoke suppression, low toxicity, and good thermal stability. However, the size of prepared borate is usually in the micrometer range, which makes it difficult to disperse in a polymer matrix, thus hindering its use as fire-retardant material. The preparation and application of borate nanomaterial as flame retardant is considered an effective method. However, the preparation of barium borate nanomaterials as flame retardant has not been reported. In this paper, nanosheets and nanoribbons with different sizes for a new barium borate BaO·4B2O3·5H2O are prepared by hydrothermal method, and characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR), thermogravimetric analysis-differential scanning calorimetry (TG-DSC), and scanning electron microscope (SEM). The flame-retardant properties of polypropylene (PP)/BaO·4B2O3·5H2O composites are investigated by thermogravimetric analysis (TG), differential scanning calorimetry (DSC) thermal analysis methods and limited oxygen index (LOI) method. Considering the near TG mass losses and the near LOI values for PP with 10% prepared BaO·4B2O3·5H2O nanosheet and nanoribbon, their flame-retardant properties need to be further evaluated by non-isothermal decomposition kinetic method. The apparent activation energy for this decomposition reaction was obtained from the slope by plotting ln(β/Tp2) against 1/Tp according to Kissinger's model. With the reduction of TG mass loss, increased heat absorption in DSC under N2 atmosphere, increased apparent activation energy Ea for the thermal decomposition of PP/BaO·4B2O3·5H2O composite as well as increased LOI value, the flame-retardant performance of prepared BaO·4B2O3·5H2O samples with PP gradually improved from bulk to nanoribbon to nanosheet. This can be attributed to the decrease in the size of BaO·4B2O3·5H2O samples because the smaller sample size leads to improved dispersion and increased contact area with the polymer. The flame-retardant mechanism is discussed by analyzing the after-flame chars of the PP/BaO·4B2O3·5H2O composite in SEM images, which show that the char layer is more compact and continuous for the PP/BaO·4B2O3·5H2O nanosheet composite. The influence of loading BaO·4B2O3·5H2O nanomaterials on the mechanical properties of PP is also tested using a universal material testing machine, in which the PP/BaO·4B2O3·5H2O nanosheet composite has higher tensile strength. The PP/BaO·4B2O3·5H2O nanosheet composite has the best flame-retardant and mechanical properties, which is promising to be developed for the application as flame-retardant material.
关键词: Barium borate, Nanomaterials, Preparation, Flame retardant performance, Mechanical property, Thermal decomposition kinetics method

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