摘要：Because of its high purity and excellent orientation, mesophase pitch is a superior precursor for high-performance car-bon materials. However, the preparation of top-notch mesophase pitch faces challenges. Catalytic polycondensation at low temperat-ures is more favorable for synthesizing mesophase pitch, because it circumvents the high-temperature free radical reaction of other thermal polycondensation approaches. The reaction is gentle and can be easily controlled. It has the potential to significantly im-prove the yield of mesophase pitch and easily introduce naphthenic characteristics into the molecules, catalytic polycondensation is therefore a preferred method of synthesizing highly spinnable mesophase pitch. This review provides a synopsis of the selective pre-treatment of the raw materials to prepare different mesophase pitches, and explains the reaction mechanism and associated research advances for different catalytic systems in recent years. Finally, how to manufacture high-quality mesophase pitch by using a cata-lyst-promoter system is summarized and proposed, which may provide a theoretical basis for the future design of high-quality pitch molecules.

摘要：p-d轨道之间的相互作用是一种提升电催化性能的有效方法.然而,其对主族金属的电催化CO_(2)还原(eCO_(2)RR)的增强机制尚不清晰.因此,我们向金属Bi纳米片中引入了一系列过渡金属氧化物(TMO:Fe_(2)O_(3)、Co_(3)O_(4)、NiO),并以此研究引入TMO对Bi物种eCO_(2)RR性能的影响.根据原位傅里叶变换红外光谱(FTIR)和CO_(2)-程序升温脱附(TPD)的结果,Bi/TMO中的TMO可以增强CO_(2)的吸附和活化能力.密度泛函理论(DFT)计算结果表明,Bi活性位点^(*)OCHO吸附能及p轨道的优化可以降低CO_(2)到^(*)OCHO过程和^(*)OCHO到HCOOH过程的理论过电位.同时,由于Bi与TMO之间因复合而发生的电子重排也促进了催化剂与反应物之间的电子传输.因此,在热力学和动力学的双重作用下,Bi/TMO中的Bi活性位点表现出最佳的催化能力,在更宽的电位区间内实现了更高的催化活性和甲酸选择性.其中,Bi/Fe_(2)O_(3)的增强效果最为显著.在500 mV的宽电位区间内达到较高的甲酸的法拉第效率(>90%),在-0.8 VRHE时,甲酸的法拉第效率达到最大值99.7%(Bi的1.11倍),甲酸局部电流密度达到12.65 mA cm^(-2)(Bi的1.86倍).这一研究不仅建立了eCO_(2)RR性能增强与引入TMO之间的关系,也为理性设计高性能电催化剂提供了一条实用的、可扩展的途径.

摘要：CoFe_(2)O_(4)has been widely used for electromagnetic wave absorption owing to its high Snoek limit,high anisotropy,and suitable saturation magnetization;however,its inherent shortcomings,including low dielectric loss,high density,and magnetic agglomeration,limit its application as an ideal *** study investigated a microstructure regulation strategy to mitigate the inherent disadvantages of pristine CoFe_(2)O_(4)synthesized via a sol–gel auto-combustion method.A series of CoFe_(2)O_(4)foams(S0.5,S1.0,and S1.5,corresponding to foams with citric acid(CA)-to-Fe(NO_(3))_(3)·9H_(2)O molar ratios of 0.5,1.0,and 1.5,respectively)with two-dimensional(2D)curved surfaces were obtained through the adjustment of CA-to-Fe^(3+)ratio,and the electromagnetic parameters were adjusted through morphology *** to the appropriate impedance matching and conductance loss provided by moderate complex permittivity,the effective absorption bandwidth(EAB)of S0.5 was as high as 7.3 GHz,exceeding those of most CoFe_(2)O_(4)-based ***,the EAB of S1.5 reached 5.0 GHz(8.9–13.9 GHz),covering most of the X band,owing to the intense polarization provided by lattice defects and the heterogeneous *** three-dimensional(3D)foam structure circumvented the high density and magnetic agglomeration issues of CoFe_(2)O_(4)nanoparticles,and the good conductivity of 2D curved surfaces could effectively elevate the complex permittivity to ameliorate the dielectric loss of pure CoFe_(2)O_(4).This study provides a novel idea for the theoretical design and practical production of lightweight and broadband pure ferrites.

摘要：At present,metal-organic framework(MOF)-derived nano-micro architectures are actively explored for electromagnetic(EM)wave absorption owing to their flexible composition and structural manipulation that enhance dielectric and magnetic ***,the basic design principles in MOF-derived microwave absorption materials have not been *** review is devoted to analyzing design principles in MOF-derived microwave absorption materials from the following perspectives:diverse monomers(ligands and ions of MOFs),topologies,chemical states,and physical *** derived essential information regarding the EM wave absorption mechanism and the structural-functional dependency is also comprehensively ***,a clear insight into the challenges and perspectives of the industrial revolution upgrading in this promising field is proposed.

摘要：用于生产高附加值燃料和化学品的电化学CO_(2)还原反应(CO_(2)RR)为实现全球碳中和提供了一种有前景的方法.近年来,单原子催化剂(SACs)由于金属的最大原子利用率和独特的催化性能受到越来越多的关注.相比之下,除了具有单原子催化剂的上述优点外,双原子位点催化剂(DASCs)还可以通过调节另一种相邻金属从而实现更复杂、可调的原子结构.作为SAC的更深层次的延伸,DASCs可以为CO_(2)RR带来新的机遇,最近引起了人们的浓厚兴趣.本文中,我们重点介绍了DASCs在提升CO_(2)RR性能方面的最新进展.首先,根据双原子活性位点的几何结构和电子配置,对DASCs的分类、合成和证实进行了讨论.之后,根据结合型、异核和同核双原子位点对DASCs在CO_(2)RR中的催化应用进行了分类.特别是通过系统地分析反应途径和原子结构,详细总结了DASCs在CO_(2)RR中的构效关系.最后,提出了未来设计DASCs面临的机遇和挑战,以启发设计具有高结构精度和高CO_(2)RR活性、选择性的DASCs.

摘要：光催化氧化有机反应是绿色催化合成转化的重要途径之一.这其中,分子氧活化过程产生活性氧物种(ROS)对促进非均相有机光合成反应选择性具有重要作用,但光催化可控分子氧活化定向生成ROS的研究尚不多见.本研究发现了共轭微孔聚合物(CMPs)的共轭度设计可诱导分子氧活化的选择性.通过CMPs共轭度的设计调控,具有强共轭结构CMP-A材料可促进分子内光生载流子的转移,而弱共轭结构CMP-D材料则会增强光生载流子在其表面的局部积累,使得CMP-A与CMP-D在光催化反应苄胺脱氢偶联与硫醚氧化方面表现出不同性能.研究证实了共轭度诱导的差异化载流子迁移过程可有效促进超氧自由基(·O_(2)^(-))和单线态氧(^(1)O_(2))的定向生成,为理性设计CMPs用以提高多种光催化有机反应的选择性提供新的思路.

摘要：Electrochemical impedance spectroscopy(EIS) and electrochemical noise(EN) techniques were used to detect stress corrosion cracking(SCC) on 40Cr steel specimens exposed to the acidified chloride solution at ambient. To test these two techniques,slow strain rate tensile(SSRT) tests were performed with 40Cr specimen in the identical corrosive solution at room temperature. In impedance measurements,phase shifts in frequency range from 1 to 1 000 Hz show a clear difference between the stressed and non-stressed specimens,suggesting that stress corrosion cracks are detected by the impedance measurements. EN signals in the process of SCC were recorded and then analyzed by standard deviation(STD). On the other hand,the mechanical properties,such as maximum tensile strength(MTS) and fracture strain(FS) measured by the SSRT,decrease significantly when the specimens are exposed to the corrosive solution relative to that in an inert medium. The SSRT results are consistent with fractography of the tested specimens by scanning electron microscopy(SEM). Analysis of the fracture surface clearly shows intergranular attack,suggesting that stress corrosion cracks are formed.

摘要：氧还原反应(ORR)是燃料电池和金属-空气电池等各种能源转换器件中重要的半反应.由于ORR的动力学缓慢,需要开发高活性电催化剂来替代常用的贵金属铂基催化剂.Fe-N-C催化剂被认为是最有前景的材料,其丰富的活性位点可以降低含氧中间体的能垒.在这篇综述中,我们详细总结了Fe-N-C催化剂在理论和实验研究方面的最新研究进展.首先,概述了基于Fe-N-C催化剂的电催化ORR的反应机理.然后,对Fe-N-C催化剂的设计策略和活性位点进行了分类.接下来,讨论了活性位点与催化性能之间的关系.介绍了Fe-N-C催化剂在燃料电池和锌空气电池中的应用现状.最后,进一步提出了Fe-N-C催化剂在可控合成、机理研究和能源器件应用方面面临的挑战和机遇.

摘要：聚三苯胺(PTPAn)因具有优异的氧化还原可逆性和结构多样性,被认为是极有前景的钠离子电池正极材料之一.然而,在实际应用中,大块体的PTPAn材料仍存在团聚和工作容量低的问题.本文通过原位聚合法将树叶状的PTPAn纳米片均匀地生长在碳纳米纤维(CNFs)表面,构建了一种自支撑的CNF@PTPAn复合电极.本文还系统探索了CNF@PTPAn复合材料中枝叶结构的形成机理,证实了原位反应的氧化速率和生长程度对调控复合电极的形貌及其活性物质含量起了关键作用.通过截止容量分析发现,PTPAn活性材料与导电CNFs之间的高效复合可以提供快速的电子/离子传输通道,有助于增强电极的深度电化学反应过程.由优化后的CNF@PTPAn复合材料所组装的钠离子半电池具有高比容量和稳定的倍率性能.在50 mA g^(-1)的电流密度下可达105 mAh g^(-1),甚至在400 mAg^(-1)的高电流密度下循环500圈后仍能保持78 mAh g^(-1)的比容量.动力学分析证明,通过调控材料在低电压区域的离子存储行为,可以有效提升其电容主导的容量贡献和扩散系数.同时,以CNF@PTPAn为正极和CNFs为负极组装的柔性CNF基全电池,在938Wkg^(-1)功率密度下表现出60Wh kg^(-1)的高能量密度.基于此,该设计有望为获得先进的自支撑电极体系提供更多的可能性.

摘要：催化效应是实现电极材料高效电化学能量转换和存储的关键因素之一.碳基复合材料因具有优异的物化性能,被广泛地合成并应用于电极材料.电极材料在能源存储器件中表现出的容量往往超过其理论容量值,额外容量的产生原因及形成机制尚未得到准确解释.本文首先回顾了储能器件的研究现状和不足,阐述了催化效应在不同类型能源存储器件中的作用:促进固体电解质界面相的演化,加速放电/充电产物的可逆转化,以及提高中间体的转化速率和活性物质的利用率,从而提升活性物质的利用.此外,还分析了催化效应与储能性能之间的相互作用,以突出催化效应的重要功能.希望本综述在系统地分析、归纳和总结的基础上,为设计具有高效催化作用的电极材料提供新思路,积极推动这一研究领域的发展.