CSP工艺含钛耐候钢中的纳米磷化物

应用透射电镜(TEM)和X射线能谱(EDX)对CSP工艺含钛耐候钢中的细小磷化物进行了研究.对成品钢板和经900℃压缩20%并等温30min的连铸坯分析结果表明:耐候钢中存在MxP型纳米级磷化物,x值为2～3,金属元素M为Fe、Ti及少量Cr或Ni,磷化物的结构为六方晶系,点阵常数a=0.609nm、c=0.351nm;成品钢板中磷化物尺寸多在20nm以下,而经过900℃压缩的连铸坯试样中磷化物的尺寸、形状不尽相同,较大的棒状磷化物长约300nm、宽约50nm,其他粒子在50nm以下,多呈方形.CSP工艺生产线中可能发生磷化物沉淀的阶段是热连轧的最后两个道次直至冷却到400～500℃的过程中;磷化物的析出可提高沉淀强化效果,但同时会使钢中的固溶磷浓度降低.     

非晶态原子团簇ConP^＋m,NinP^＋m的生成与结构分析

应用量子化学从头计算方法研究了激光等离子体反应生成的非晶团簇ＣｏｎＰ＋ｍ、ＮｉｎＰ＋ｍ．考查和分析了可能的几何构型及稳定性．ＣｏｎＰ＋ｍ有两条生长螺线：１）从ｍ＝４到ｍ＝８,构型变化为四边形→三角双锥→畸变八面体→双四面体;２）从ｍ＝７到ｍ＝１１,构型变化为三棱柱加帽→长方体→四棱柱加帽→五棱柱,其中Ｃｏ嵌在多面体中．ＮｉＰ＋ｍ只有一条生长螺线ＮｉＰ＋７～ＮｉＰ＋１１,Ｐｍ形成网络,Ｎｉ仅与其中部分Ｐ原子成键．     

锂–硫电池硫正极的金属磷化物和硫化物催化载体

Lithium?sulfur batteries are one of the most competitive high-energy batteries due to their high theoretical energy density of 2600 W·h·kg?1. However, their commercialization is limited by poor cycle stability mainly due to the low intrinsic electrical conductivity of sulfur and its discharged products (Li₂S₂/Li₂S), the sluggish reaction kinetics of sulfur cathode, and the “shuttle effect” of soluble intermediate lithium polysulfides in ether-based electrolyte. To address these challenges, catalytic hosts have recently been introduced in sulfur cathodes to enhance the conversion of soluble polysulfides to the final solid products and thus prevent the dissolution and loss of active-sulfur material. In this review, we summarize the recent progress on the use of metal phosphides and borides of different dimensions as the catalytic host of sulfur cathodes and demonstrate the catalytic conversion mechanism of sulfur cathodes with the help of metal phosphides and borides for high-energy and long-life lithium–sulfur batteries. Finally, future outlooks are proposed on developing advanced catalytic host materials to improve battery performance.     

过渡金属磷化物氢等离子体还原法制备及其加氢脱硫性能

采用氢等离子体还原法制备了体相过渡金属磷化物Ni2P、MoP、WP和CoP．新鲜制备的金属磷化物在移入固定床反应器之前,用10％Hz孓Hz或0．5％O2—Ar进行钝化,以保护其结构．研究发现,氢等离子体还原法制备的磷化物催化剂的加氢脱硫活性高于程序升温还原（TPR）法制备的催化剂．XRD表征和CO化学吸附结果表明,氢等离子体还原法制备的金属磷化物的粒度较小,活性中心较多．氢等离子体还原法制备的金属磷化物催化剂的高活性可归于其活性中心数量的增加．     

Multicomponent transition metal phosphide for oxygen evolution

Transition metal phosphides(TMPs)have exhibited decent performance in an oxygen evolution reaction(OER),which is a kinetic bottleneck in many energy storages and conversion systems.Most reported catalysts are composed of three or fewer metallic components.The inherent complexity of multicomponent TMPs with more than four metallic components hinders their investigation in rationally designing the structure and,more importantly,comprehending the component-activity correlation.Through hydrothermal growth and subsequent phosphor-ization,we reported a facile strategy for combining TMPs with tunable elemental compositions(Ni,Fe,Mn,Co,Cu)on a two-dimensional ti-tanium carbide(MXene)flake.The obtained TMPs/MXene hybrid nanostructures demonstrate homogeneously distributed elements.They ex-hibit high electrical conductivity and strong interfacial interaction,resulting in an accelerated reaction kinetics and long-term stability.The res-ults of different component catalysts’OER performance show that NiFeMnCoP/MXene is the most active catalyst,with a low overpotential of 240 mV at 10 mA·cm?2,a small Tafel slope of 41.43 mV·dec?1,and a robust long-term electrochemical stability.According to the electrocata-lytic mechanism investigation,the enhanced NiFeMnCoP/MXene OER performance is due to the strong synergistic effect of the multi-ele-mental composition.Our work,therefore,provides a scalable synthesis route for multi-elemental TMPs and a valuable guideline for efficient MXene-supported catalysts design.