钙钛矿型锰的氧化物制备及其对空气电极的催化性能研究

利用溶胶-凝胶法制得钙钛矿型La_(0.9)Sr_(0.1)MnO_3催化剂,通过XRD测试和SEM测试,对其物象和形貌进行表征,结果表明,得到了高纯度的钙钛矿。将催化剂制成电极,通过极化曲线分析和交流阻抗拟合分析,电极在-0. 2 V电位下,电流密度为62 m A/cm~2,La_(0.9)Sr_(0.1)MnO_3催化剂显示出了良好的氧还原催化性能。组装成锌-空气电池进行测试,在40 m A/cm~2电流密度下循环进行充放电,充电电压保持在2. 3 V左右,而放电电压保持在1. 1 V左右,可持续稳定循环80 h。     

锌-空气电池Co-PPy-C复合催化剂的电化学性能研究

采用化学氧化聚合法合成了以碳为载体的钴-聚吡咯(PPy)配合物Co-PPy-C,作为气体扩散电极的氧还原催化剂。利用极化曲线、交流阻抗、计时电流等电化学方法测试了其在碱性介质中(6 mol/L KOH)氧气气氛条件下氧还原的催化性能。电极电位在-0.20 V vs.Hg/HgO时,催化剂电流密度达到158 mA/cm2,显示出优越的氧还原电催化性能;采取催化层/集流体/气体扩散层的排布方式,以纯锌为负极,6 mol/L的KOH为电解液,将气体扩散电极与锌负极组装成锌-空气电池。电池以80 mA/cm2进行恒流放电,放电电压为1.0 V,且性能稳定。     

石墨烯/Sr2Ni0.4Co1.6O6复合材料的制备及其性能

通过溶胶-凝胶法合成了双钙钛矿型氧化物Sr_2Ni_(0.4)Co_(1.6)O_6、通过改性Hummers还原方法制备出薄层石墨烯,并制备单一物质和两者复合材料的双功能氧电极,用于测试其氧催化性能。采用XRD、EDS、SEM、FTIR对样品进行表征。结果显示:Sr_2Ni_(0.4)Co_(1.6)O_6均匀地分布于薄层石墨烯片层表面。电化学性能测试结果表明:单一Sr_2Ni_(0.4)Co_(1.6)O_6和薄层石墨烯的氧还原反应(ORR)最大电流密度分别为0.1830、0.1516A/cm~2 (–0.6Vvs.Hg/Hg O),氧析出反应(OER)最大电流密度分别为0.2677、0.1174 A/cm~2 (1 V vs. Hg/HgO)。当薄层石墨烯添加量占复合催化剂质量的10%时,复合催化剂的氧催化性能最佳,ORR最大电流密度为0.2901 A/cm~2(–0.6Vvs.Hg/Hg O),OER最大电流密度为0.3905 A/cm~2 (1 V vs. Hg/HgO),明显高于单一催化剂。     

碳材料改性锌负极的复合锌离子电池电化学性能的研究

采用涂布法分别将碳纳米管(CNT)和氧化石墨(GO)涂布在铜箔(Cu)上制成Cu/CNT和Cu/GO复合集流体,随后在复合集流体表面电沉积锌(Zn)制成Cu/CNT/Zn和Cu/GO/Zn复合电极作为锌负极,并通过扫描电子显微镜(SEM)观察微观形貌。结果表明,可以发现锌在两种复合集流体上均为不规则片状,且由于氧化石墨的尺寸大于碳纳米管,其表面的锌片尺寸也略大于碳纳米管表面的锌片尺寸。在电流密度为0.5 mA/cm²的循环测试中,Cu/CNT/Zn||Cu/CNT/Zn复合对称电池保持极化电压在0.02 V以内正常运行了50 h,而Cu/GO/Zn||Cu/GO/Zn复合对称电池保持极化电压在0.04 V以内正常运行了160 h。在全电池的电化学性能测试中, MnO_2||Cu/CNT/Zn和MnO_2||Cu/GO/Zn复合锌离子电池均表现出高于MnO_2||Zn电池的容量。     

整体构件型La_(0.8)Sr_(0.2)MnO_3催化剂的制备和催化燃烧特性

为了解不同整体构件钙钛矿催化剂的VOCs催化燃烧特性,以不锈钢316L丝网和堇青石蜂窝陶瓷为基材,通过电泳沉积和浸涂技术在基材表面均匀涂覆γ-Al_2O_3粘合层,再在涂层表面负载钙钛矿型2.0%(wt)的La_(0.8)Sr_(0.2)MnO_3活性组分.SEM表征发现100 nm左右的La_(0.8)Sr_(0.2)MnO_3颗粒可以均匀、牢固地分散在不锈钢丝网和蜂窝陶瓷表面,经过550℃焙烧后无龟裂现象.超声振荡30 min后,活性组分损失率均小于5.0%(wt).甲苯催化燃烧测试表明,金属丝网型、蜂窝陶瓷型和颗粒型La_(0.8)Sr_(0.2)MnO_3催化剂表现出相似的催化性能,但金属丝网具有更好的传质效果和热响应速率,更适合处理高空速、温度和浓度波动较大的有机废气.     

铁氮改性纳米金刚石的制备及其电化学性能研究

利用爆轰纳米金刚石(ND)导热性极强的特点，将尺寸较小的反应物前驱体分布在ND表面后产生需要的金属盐再进行氮掺杂，成功制备出高效氧还原反应催化剂Fe-NND并应用于锌-空电池。结果表明，其ORR反应过程电子转移数为3.91,起始电位为0.903 6 V,电流密度高达5.225 mA/cm²,且经过6 000圈CV循环其半波电位仅下降26 mV。在锌-空电池上的峰值功率密度为91.81 mW/cm²,比容量高达847 mA·h/g。     

新型双钙钛矿基对称固体氧化物燃料电池的制备及性能

采用柠檬酸-硝酸盐燃烧法制备PrBaFe_2O_(5+δ)(PBFO)和PrBaFe_(1.6)Ni_(0.4)O_(5+δ)(PBFNO)电极材料,用高温固相法制备La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(3–δ)(LSGM)电解质。以LSGM为电解质,PBFNO及PBFNO-SDC分别为对称电极制备单电池。利用X射线衍射法研究材料的物相结构,交流阻抗法记录界面极化行为,扫描电子显微镜观察电池的断面微结构,用自组装的测试系统评价电池输出性能。结果表明:合成的PBFO和PBFNO粉体呈现单一的钙钛矿结构;Ni掺杂能够明显改善空气气氛下的界面极化行为,800℃时电极–电解质的界面极化阻抗由1.94?·cm~2降低到0.39?·cm~2。通过PBFNO与SDC复合能够明显增大电极的三相反应界面,提高电池输出性能,单电池在800℃时的最大功率输出密度从332mW/cm~2增大到372mW/cm~2。PBFNO-SDC复合电极是潜在的对称固体氧化物燃料电池电极材料。     

LSMO底电极对Pr_(0.7)Ca_(0.3)MnO_3阻变性能的改善

采用脉冲激光沉积技术制备了Ti/Pr_(0.7)Ca_(0.3)MnO_3/Pt(Ti/PCMO/Pt)和底电极为La_(0.67)Sr_(0.33)MnO_3(LSMO)的Ti/Pr_(0.7)Ca_(0.3)MnO_3/La_(0.67)Sr_(0.33)MnO_3(Ti/PCMO/LSMO)异质结。与Ti/PCMO/Pt相比,Ti/PCMO/LSMO的阻变性能尤其是电阻转变比率得到了显著的改善。对LSMO底电极改善器件电致电阻转变特性的机理进行了定性的分析。     

固体聚合物电解水制氢性能衰减分析

以阳极催化剂（IrO₂）、阴极催化剂（Pt/C）含量、阴极Nafion质量分数和阳极Nafion质量分数为考察的因素，进行了四因素三水平的正交试验，以电解槽电解电压在2V时的电流密度为衡量标准，确定了配置催化剂浆料的最优配比为：阳极催化剂IrO₂担载量2.0mg/cm²，阴极催化剂Pt担载量1.0mg/cm²，阳极催化剂浆料中Nafion质量分数20%，阴极催化剂浆料中Nafion质量分数25%。使用最优配比配制催化剂后制备膜电极，对该膜电极进行极化曲线测试、产氢量计算及稳定性测试，发现运行80h后，膜电极的电解性能下降，在0.6A/cm²时，电解电压从1.78V升高到2.06V。使用交流阻抗分析稳定性测试前后的各部分电阻变化，发现各部分电阻均有增加。扫描电镜发现测试后阴极催化层与膜发生明显剥离。对稳定性测试期间的循环水进行电感耦合等离子体质谱（ICP-MS）测试，发现长时间运行后，水中Ir和Pt的含量增加。     

金属丝网型La0.8Sr0.2MnO3催化剂对有机废气催化燃烧的特性

以316L不锈钢丝网为载体,采用电泳沉积法和热处理技术在丝网表面包覆一层具有高粘结强度和较高比表面积的表面Al_2O_3/Al粘合层,再利用湿浸涂技术在丝网表面负载纳米钙钛矿型稀土复合氧化物La_(0.8) Sr_(0.2)MnO_3催化剂。以甲苯、二甲苯和丙酮的催化燃烧反应为模型反应,考察了催化剂的催化性能和反应特性.结果表明,La_(0.8) Sr_(0.2) MnO_3催化剂在丝网表面具有较强的粘结强度,在强放热反应中具有传热速率快,催化剂床层整体均温性好的特性,具有较好的催化燃烧活性和稳定性.     

乙苯,苯乙烯的生产及合成乙苯,苯乙烯催化剂的研究进展

苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况，合成乙苯，苯乙烯所用的催化剂种类，并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。     

Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile

Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, ¹³C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc.     

生物质气化及生物质与煤共气化技术的研发与应用

总结了生物质原料的特点及生物质单独气化的缺点;介绍了国内外生物质气化技术及生物质与煤共气化技术的研发与应用现状;分析了在此领域国内外的发展趋势与前景;概括了开展生物质与煤共气化技术研发的意义。     

责任和责任心的涵义与结构

责任是人应主动承担的角色义务和对其因过失所造成后果应承担的责罚.有两层涵义:一是义务;二是后果.责任心是个体自觉做好分内事务和履行道德义务的心理倾向,是个性心理品质成分中自我特征维度上的重要内容.责任心具有两个方面的涵义:一是角色分内职责;二是角色道德义务.责任心是一种通过责任认知、责任个性和责任适应的动态形式表现出来的静态品质,责任心是责任心过程结构与责任心关系结构相互制约、相互影响的统一体.     

二甲基二烯丙基氯化铵和丙烯酰胺的合成及应用

用复合引发体系(过硫酸盐-偶氮类引发剂)和脂肪胺类氧化还原体系引发,在实验室获得了单体转化率≥98%,特性粘数高于13.6 dL/g的阳离子共聚物PDA,探讨了控制聚合物分子量的影响因素.     

Comparison of the Adhesion and Cohesion of Triblock and Random Copolymers of Styrene and Butadiene

A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength.     

钾盐资源及钾肥供需情况分析及预测

阐述了国内外钾盐资源及钾肥生产现状,对国内外钾盐的供需形势进行了分析及预测,从资源、原材料、国际市场三方面提出了解决我国钾盐短缺的措施。     

Electronic structures and reactivities of monometallic and bimetallic clusters of Au and Cu

The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu₃Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu₃Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters.     

Wetting properties of homopolymers and copolymers of pentafluorostyrene and methylacrylate and homopolymer blends

Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method¹ was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity.