Simulation Study on Front Impact Safety of Medium Coach

建立半承载式中型客车的正面碰撞有限元模型,采用lS-dynA软件进行仿真分析。结果表明,该车驾驶室变形较大、完整性较差,需对客车前部吸能结构进行优化设计。The finite element model of front impact of medium coach is built,which body is semi-integral type.Using LS-DYNA software,the front impact safety is simulated.The results indicate that the drive cab deformation is bigger and its integrality is worse,so it is necessary to optimize the front absorbing structure components to the coach drive cab.交通部西部交通科技项目(2009318000043);福建省教育厅科技项目(JA11239);厦门理工学院科技项目(JKY10023R);福建省自然科学基本项目(2012J05103

Effects of the Surfactant and pH on Linear Potential Scan of Aqueous Na 2S Solution

In presence of a cationic surfactant HTAB,linear potential scans for Na 2S at graphite anode in both saturated sodium tetra_borate solution and 1 mol·L -1 NaOH solution, have been investigated.Results show that anodic current density increases and peak potentials shift to more negative with the increase of HTAB concentrations. The anodic current densities increased by addition of HTAB are larger in 1 mol·L -1 NaOH than those in saturated sodium tetra_borate solution,resulting from different acting forces of HTAB with various charged electro-active species .Both oxidation and reduction peaks in cyclic voltammograms for Na 2S containing solution become sharper if HTAB is present in the anolyte. The appearance of several reduction peaks indicates that intermediate polysulfides are produced in negative-going scan.作者联系地址：湘潭工学院化工系!湘潭411201,中南工业大学化学系!长沙410083,中南工业大学化学系!长沙410083Author's Address: Chem.Eng.Dept.of Xiangtan Polytechnic University,Xiangtan 411201 Chen Qiyuan Zhang Pingmin Chem. Dept. of Central South Univ. of Technology,Changsha 41008

A Titanium-Supported Nanoporous Pd Electrocatalyst for Methanol Oxidation

采用水热法,以甲醛作还原剂还原Pd2+-EDTA络合物,制得钛基纳米钯颗粒电极(nanoPd/Ti).扫描电子显微镜(SEM)显示,纳米钯颗粒直径约为60 nm,形成三维立体网状结构.在碱性溶液中,循环伏安及交流阻抗测试分别表明:nanoPd/Ti电极对甲醇氧化有极高的阳极电流、较低的起始氧化电位和较强的抗CO毒化能力.在nanoPd/Ti电极上甲醇电氧化反应的阻抗值较低,增加甲醇浓度,电极阻抗更低.电极对甲醇氧化具有极好的电催化活性.Titanium-supported nanoporous palladium electrode(nanoPd /Ti) was prepared by a hydrothermal process in the presence of the ligand EDTA and using formaldehyde as reducing agent.SEM images showed that the size of Pd particles was about 60 nm and the Pd particles were connected with each other to form a three-dimensional network structure.Cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) were applied to evaluate the electrocatalytic activity of the nanoPd/Ti electrode towards methanol oxidation in alkaline solution.CV results showed that the nanoPd /Ti electrode presented high anodic peak densities and a low onset potential for methanol oxidation.Also nanoPd /Ti electrode showed excellent CO tolerance during the oxidation of methanol.Nyquist and Bode plots of electrochemical impedance showed that methanol electro-oxidation on the nanoPd /Ti exhibited low impedance values,and that with the increase of methanol concentrations,the impedance value for methanol electrooxidation decreaseed,indicating the significantly high electroactivity of the prepared nanoporous Pd electrode for methanol oxidation.作者联系地址：湖南科技大学化学化工学院;Author's Address: School of Chemistry and Chemical Engineering,Hunan University of Science and Technology,Xiangtan 411201,Hunan,Chin

Lead Modified Nanoporous Platinum Electro-Catalysts for Formic Acid Oxidation

用合适金属修饰的铂催化剂能够显著增强其对甲酸氧化的电活性. 本文以水热法制备了钛负载的纳米多孔铂电极（nanoPt/Ti），然后采用循环伏安法，通过扫描不同的周数（n），用适量的铅对nanoPt/Ti电极进行修饰，得到一种新型的铅修饰的纳米多孔铂电极（nanoPb(n)-Pt/Ti）. 采用循环伏安（CV）、计时电流和计时电位法研究其对对甲酸氧化的电活性. CV结果显示nanoPt/Ti和nanoPb(n)-Pt/Ti电极对甲酸氧化表现出较高的催化活性，并且nanoPb(20)-Pt/Ti电极对甲酸氧化的起始电位为-0.06 V，相比nanoPt/Ti电极的起始电位（0.06 V），明显有所负移. 此外，nanoPb(20)-Pt/Ti电极的第一个氧化峰电流密度为12.7 mA·cm-2，远远大于nanoPt电极（4.4 mA·cm-2）；计时电流显示在电位为0.1 V时，在0.5 mol·L-1 H2SO4 + 1 mol·L-1 HCOOH溶液中，nanoPb(20)-Pt/Ti电极达到稳定时的电流为8.09 mA·cm-2，是nanoPt电极的60倍，表明铅修饰的nanoPt/Ti对甲酸氧化的电活性急剧增加；在1.5 mA、2 mA、2.2 mA和2.5 mA下的计时电位结果表明，nanoPb(20)-Pt/Ti电极上甲酸氧化过程表现出显著的电化学振荡，且和nanoPt/Ti电极相比，振荡现象能持续更长的时间，说明nanoPb(20)-Pt/Ti电极具有更强的表面抗毒化能力.Platinum (Pt) catalysts modified by other suitable metals significantly enhance their electrochemical activities for formic acid oxidation. In this work, a titanium-supported nanoporous network platinum (nanoPt/Ti) electrode was prepared using a hydrothermal method. The as-prepared nanoPt/Ti electrode was modified with a certain amount of lead by using cyclic voltammetry for different scan cycle numbers (n), namely, n = 10, 15, 20 and 30, to synthesize the novel lead-modified nanoporous Pt (nanoPb(n)-Pt/Ti) electrodes. Electro-oxidation of formic acid on these electrodes was studied with cyclic voltammetry (CV), chronoamperometry and chronopotentiometry in sulfuric acid solution. CV curves showed that both nanoPt/Ti and nanoPb(n)-Pt/Ti electrodes displayed high electrocatalytic activities for formic acid oxidation, and the onset potential of formic acid oxidation on the nanoPb(20)-Pt/Ti electrode was -0.06 V, which was more negative than that on the nanoPt/Ti electrode (0.06 V). In addition, the first oxidation peak current density on the nanoPb(20)-Pt/Ti electrode was 12.7 mA·cm-2, which was far larger than that on the nanoPt electrode (4.4 mA·cm-2). Chronoamperommetric data at 0.1 V in 0.5 mol·L-1 H2SO4 + 1 mol·L-1 HCOOH suggested that the nanoPb(20)-Pt/Ti electrode exhibited the stable current density of 8.09 mA·cm-2 which was 60 times higher than the nanoPt electrode, indicating the dramatic enhancement of electroactivity on the lead-modified nanoPt/Ti electrode for formic acid oxidation with comparison to the nanoPt/Ti electrode. Chronopotentiometric responses on the electrode at 1.5 mA, 2 mA, 2.2 mA and 2.5 mA in 0.5 mol·L-1 H2SO4 + 1 mol·L-1 HCOOH revealed notable electrochemical oscillations which lasted longer time than those on the nanoPt/Ti electrode. It was demonstrated that the lead-modified nanoPb(20)-Pt/Ti electrode presented the most significant enhancement on surface anti-poisoning ability.国家自然科学基金项目（21376070）National Natural Science Foundation of China(21376070)作者联系地址：湖南科技大学化学化工学院，湖南 湘潭，411201Author's Address: School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201, Hunan, China通讯作者E-mail：[email protected]

Electroactivities of Pd/Fe3O4-C catalysts for electro-oxidation of methanol, ethanol and propanol

制备对醇氧化反应具有优异电活性的钯催化剂是醇燃料电池研究的重要内容。本文用硼氢化钠还原法制备了钯纳米颗粒, 然后沉积在Fe3O4/C复合物表面, 得到了不同Fe3O4负载量的Pd/Fe3O4-C催化剂. 透射电镜（TEM）图显示钯纳米颗粒均匀地分散在Fe3O4/C表面. 对制备好的Pd/Fe3O4-C催化剂进行了循环伏安法（CV）、计时电流（CA）和电化学阻抗谱（EIS）的测试, 研究了其在碱性介质中对C1-C3醇类（甲醇、乙醇和丙醇）氧化的电催化活性. 结果表明, 所制备的不同Fe3O4负载量的Pd/Fe3O4(2%)-C,Pd/Fe3O4(5%)-C, Pd/Fe3O4(10%)-C和Pd/C催化剂中, Pd/Fe3O4(5%)-C催化剂表现出最高的醇氧化电流密度. 依据循环伏安（CV）数据，Pd/Fe3O4(5%)-C催化剂对甲醇、乙醇、正丙醇和异丙醇氧化的阳极峰电流密度分别是Pd/C催化剂的1.7、1.4、1.7和1.3倍. Pd/Fe3O4(5%)-C催化剂对乙醇氧化的电荷传递电阻也远低于Pd/C催化剂. 制备的所有催化剂对C1-C3醇类电氧化的电流密度大小排序如下: 正丙醇﹥乙醇﹥甲醇﹥异丙醇. 此外, 碳粉中Fe3O4纳米颗粒的存在提高了钯纳米颗粒的电化学稳定性.Development of palladium (Pd) catalysts with high electroactivity for alcohol oxidation is significant for alcohol fuel cells. In this work, Pd nanoparticles were formed by sodium borohydride (NaBH4) reduction method and subsequently deposited on the surface of carbon supported ferriferrous oxide (Fe3O4/C) composites to obtain the Pd/Fe3O4-C catalysts with different Fe3O4 loadings. Their transmission electron microscopic (TEM) images show that the Pd nanoparticles were uniformly dispersed on the Fe3O4/C. Electroactivities of the prepared Pd/Fe3O4-C catalysts toward oxidations of C1-C3 alcohols (methanol, ethanol, n-propanol and iso-propanol) in alkaline media were investigated by cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy. Among the prepared catalysts (Pd/Fe3O4(2%)-C, Pd/Fe3O4(5%)-C, Pd/Fe3O4(10%)-C and Pd/C), the Pd/Fe3O4(5%)-C catalyst presented the highest electro-oxidation current density for oxidations of C1-C3 alcohols. According to the CV data, the anodic peak current densities for oxidations of methanol, ethanol, n-propanol and iso-propanol on the Pd/Fe3O4(5%)-C catalyst were over 1.7, 1.4, 1.7 and 1.3 times larger than that on the Pd/C catalyst, respectively. Furthermore, the charge transfer resistance of ethanol oxidation on the Pd/Fe3O4(5%)-C catalyst was much lower than that on the Pd/C catalyst. For all of the prepared catalysts, the decreases in electro-oxidation current density of the tested C1-C3 alcohols followed the order of n-propanol >ethanol > methanol >iso-propanol. In addition, the presence of Fe3O4 nanoparticles in the carbon powder improved the electrochemical stability of the Pd nanoparticles.国家自然科学基金项目(21376070)，湖南省研究生科研创新项目(CX2016B567)资助作者联系地址：1.湖南科技大学，化学化工学院，中国,湘潭，411201；2.理论有机化学与功能分子教育部重点实验室，中国湖南，湘潭，411201Author's Address: 1.School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201, China; 2.Key Laboratory of Theoretical Organic Chemistry and Functional Molecule, Ministry of Education, Xiangtan 411201, Hunan, China通讯作者E-mail：[email protected]