锂空气电池空气电极层次多孔碳的制备及其性能

在不同表面活性剂浓度下通过溶胶-凝胶自组装方法制备了具有介孔结构的层次多孔碳材料（HPCs）。用场发射扫描电镜（FE-SEM）、透射电镜（TEM）、氮气吸脱附测试和恒流充放电测试对样品进行物理和电化学性能研究。结果表明：所有的HPCs主要为介孔结构并且具有相似的孔径分布。以HPCs为空气电极载体碳材料的锂空气电池具有较高的放电容量。且相似孔径大小的碳材料为载体的锂空气电池放电容量随着碳材料的比表面积增加而增加。在c（CTAB）=0.27 mol/L时制备的HPCs-3样品具有最佳的电化学性能。通过控制放电深度至800 mA·h/g,电池表现出良好的容量保持率,在0.1 mA/cm2电流密度下,首次放电容量为2050 mA·h/g。     

用于氧还原反应的铂基催化剂研究进展

铂基催化剂是传统高效的质子交换膜燃料电池(PEMFC)阴极氧还原反应(ORR)催化剂,提高燃料电池性能的同时降低成本是研究重点。基于50余篇文献的分析,总结了铂基ORR催化剂基于性能的调控策略,包括调控粒径、组分和形貌,综述了铂基纳米粒子、单原子(SAC)、合金、高熵合金(HEA)、纳米线和纳米片催化剂的研究进展,探讨了铂基ORR催化剂研究存在的挑战,并对其未来发展进行了展望。     

电化学作用对直流焊接熔滴金属致氧量的影响

在对熔滴金属电化学致氧动力学分析基础上,用试验室自行设计制作的不同碱度系列烧结焊剂,采用在水冷铜板表面进行快速直流埋弧焊接方法提取出无熔池熔滴金属,以获取出熔滴金属质量几何信息并进而进行冶金电化学致氧量分析.结果表明,随着熔渣碱度的增大,钢-渣界面电化学作用愈加强烈,冶金电化学致氧量也愈加突出.就所研究CaO-Al2O3-SiO2渣系而言,当碱度值增至1.52时,冶金电化学致氧程度几乎可以达到与冶金热化学相当的程度,因而在直流焊接工艺制订及高碱度焊接材料研制中是一不可忽视的冶金致氧因素.     

多孔Ag@Ni泡沫金属的制备及其在非水性锂空气电池上的应用

通过改进的置换反应,以三维网状结构泡沫镍为基底,制备了新型多孔Ag/Ni复合泡沫金属材料(Ag@Ni泡沫金属)。X射线衍射(XRD)、扫描电子显微镜(SEM)和X射线能谱(EDS)表明,泡沫镍基底上生成的金属Ag颗粒呈枝晶状且分布均匀。将其作为集流体首次应用于锂空气一次电池正极,通过线性伏安扫描(LSV)、电化学阻抗(EIS)和充放电测试研究了电极的电化学性能,结果表明,这种Ag@Ni泡沫金属作为锂空气一次电池的氧气极集流体,明显提高了还原反应的催化活性,改善了电化学反应性能,电流密度0.1 mA/cm2时,放电电压平台从2.66升高到2.73 V,容量也由2000 mAh/g增大到2750 mAh/g,且大电流密度下改善更为明显。     

Manufacture,characterization and application of porous metal-fiber sintered felt used as mass-transfer controlling medium for direct methanol fuel cells

Fabrication, characterization and performance of a porous metal-fiber sintered felt (PMFSF) based on multi-tooth cutting and solid-phase sintering were studied. The PMFSF was used as the anodic methanol barrier in a passive air-breathing direct methanol fuel cell to mitigate the effects of methanol crossover. Compared with the commercial SUS316L felt made of bundle-drawn fibers, this self-made PMFSF has larger pore diameter, polarized pore distribution, irregular fiber shape, rougher surface, lower mass flow resistance and evident hydrophobicity. The results reveal that the use of a PMFSF significantly enhances the cell performance since it helps to maintain a balance between the reactant and product management while depressing methanol crossover. The PMFSF with a porosity of 70% yields the highest cell performance at a methanol concentration of 4 mol/L.     

PtCo纳米晶的溶剂热法制备、表征及电催化性能研究

采用溶剂热法以不同加热时间制备PtCo纳米晶,研究晶粒的生长过程及电催化性能。随着制备加热时间的延长,透射电镜(TEM)表征显示,纳米晶从球形变为八面体,粒径逐渐增大,晶面间距减小;结合能谱分析的结果,表明更多的钴被还原进入纳米晶粒内。对PtCo纳米晶制备的电极进行电化学分析,随着制备加热时间延长,循环伏安(CV)曲线显示氢脱附峰面积先增大后减小,线性扫描伏安法(LSV)表明,氧还原电催化活性先变大后减小。加热12 h制备的纳米晶制备的电极电催化活性(358 mA/mgPt)最佳,约为商用Pt/C的2.2倍。     

Recent Progress in Carbon-based Materials of Non-Noble Metal Catalysts for ORR in Acidic Environment

Proton exchange membrane fuel cell(PEMFC) has important implications for the success of clean transportation in the future.One of the key factors affecting the cost and performance of PEMFC is the cathode electrocatalyst for the oxygen reduction reaction(ORR) to overcome sluggish kinetics and instability in an acidic environment.As an essential component of the electrocatalyst,the support material largely determines the activity,mass transfer,charge transfer,and durability of the electrocatalyst.Thereby,the support material plays a critical role in the overall performance of the electrocatalyst.Carbonbased materials are widely used as electrocatalyst supports because of their high porosity,conductivity,chemical stability,and tunable morphology.Recently,some new carbon-based materials with excellent structure have been introduced,such as carbon nanotubes,carbon nanowires,graphene,metal-organic framework(MOF)-derived carbon,and biomass-derived carbon materials.Combined with a variety of strategies,such as controllable construction of porous structures and surface defects,proper doping heteroatoms,the ingenious design of model electrocatalysts,and predictive theoretical calculation,a new reliable path was provided for further improving the performance of electrocatalysts and exploring the catalytic mechanism.Based on the topic of carbon-based materials for ORR in acidic medium,this review summarizes the up-to-date progress and breakthroughs,highlights the factors affecting the catalytic activity and stability of ORR electrocatalysts in acids,and discusses their future application and development.     

人工髋关节摩擦界面蛋白质吸附变性分解行为及类石墨碳润滑层形成的分子机制

人工关节置换术被认为是治疗晚期关节炎、关节功能丧失等关节类疾病最有效和最终的治疗方式。首先介绍了人工髋关节体内服役环境特点及关节摩擦界面生物蛋白膜与类石墨碳润滑层的形成,进一步论述了在模拟体内服役环境下,过渡族金属铜催化摩擦界面的蛋白质变性降解,促进生物蛋白膜向类石墨碳润滑层的转变,最后探讨了过渡族金属离子介导产生活性氧自由基(ROS)催化蛋白质吸附、变性、分解及生物蛋白膜、类石墨碳润滑层形成的分子机制,并对未来陶瓷人工关节材料的设计提出展望。