Exciting lattice oxygen of nickel–iron bi-metal alkoxide for efficient electrochemical oxygen evolution reaction

High efficiency,cost-effective and durable electrocatalysts are of pivotal importance in energy conversion and storage systems.The electro-oxidation of water to oxygen plays a crucial role in such energy conversion technologies.Herein,we report a robust method for the synthesis of a bimetallic alkoxide for efficient oxygen evolution reaction(OER)for alkaline electrolysis,which yields current density of 10 mA cm^(-2)at an overpotential of 215 mV in 0.1 M KOH electrolyte.The catalyst demonstrates an excellent durability for more than 540 h operation with negligible degradation in activity.Raman spectra revealed that the catalyst underwent structure reconstruction during OER,evolving into oxyhydroxide,which was the active site proceeding OER in alkaline electrolyte.In-situ synchrotron X-ray absorption experiment combined with density functional theory calculation suggests a lattice oxygen involved electrocatalytic reaction mechanism for the in-situ generated nickel–iron bimetal-oxyhydroxide catalyst.This mechanism together with the synergy between nickel and iron are responsible for the enhanced catalytic activity and durability.These findings provide promising strategies for the rational design of nonnoble metal OER catalysts.

Cu-Co bi-metal catalyst prepared by perovskite CuO/LaCoO_3 used for higher alcohol synthesis from syngas

Cu-Co bi-metal catalysts derived from CuO/LaCoO3 perovskite structure were prepared by one-step citrate complexing method, and the structure evolution reaction from CuO/LaCoO3 to Cu-Co2C/La202CO3 under 1-12 pretreatment was investigated by techniques of XRD, TPR and TEM. The results suggest that a much higher dispersion of copper significantly enhanced the reduction of cobalt, and a stronger interaction between copper and cobalt ions in LaCoO3 particles led to the formation of bi-metallic Cu-Co particles in the reduced catalysts and the enrichment of Co on the surface of bimetallic particles. The prepared catalysts were highly active and selective for the alcohol synthesis from syngas due to the presence of copper-modified C02C species.

Perovskite LaFeO_3 supported bi-metal catalyst for syngas methanation

LaFeO3 perovskite supported Ni and Ni-Fe catalysts were prepared and applied to methanation reaction of syngas.Two preparation methods were employed.One was one-step citrate complexing method,and the other was a two step method using citrate complexing method to produce LaFeO3 and followed by loading nickel oxide on it with impregnation.The structure evolution of the sample as prepared was investigated by XRD,TPR and TEM techniques.For the former,the chemical composites of the calcined sample are NiO-Fe2O3/LaFe1-xNix O3.After reduction and reaction of CO methanation,its composites convert to Fe-Ni@Ni/LaFeO3-La2O2CO3,in which Fe-Ni@Ni is metal particles in nano-size composed of nickel core and Fe-Ni alloy shell.For the latter,the chemical composites of the calcined sample are NiO/LaFeO3; and after reduction and reaction of CO methanation,its chemical composites change to Ni/LaFeO3.Ni/LaFeO3 catalyst is a little more active, while Fe-Ni@Ni/LaFeO3-La2O2CO3 is much more stable and shows very good resistance to carbon deposition.In this work it is aimed to show that the structure and composites of the catalysts can be tailored using perovskite-type oxide as precursor prepared with different methods and conditions.Therefore,it is a promising route to prepare supported bi-metal catalysts in nano-size for a lot of metals with desired catalytic performances.

Observation of interface of two kinds of bi-metal composite parts prepared by thixo-forging

Two kinds of bi-metal composite parts (Sn-15%Pb and Pb-22%Sn bi-metal system, and Al-7%Si and SiCp/6061 MMC bi-metal system) were prepared by the strain-induced melt activated thixo-forging.The interfaces of the bi-metal composites were observed by OM and SEM.The observations show that the semisolid metals keep independence during thixo-forging.The solid phases in the semisolid slurries maintain their original morphologies after thixo-forging.The liquid phases near the interface mix together and form a thin layer.The interfaces are bonded firmly with the metallurgical bonding.No oxide layers are found at the interfaces.Strengths of the interfaces were investigated by the micro-hardness test.The experimental results show that the composite interfaces have high strength.However, the agglomerated enhancing particles cause fine defect on the interface of the Al-7%Si and SiCp/6061 MMC bi-metal composite.

Impacts of zinc layer and pouring method on interface performance for Al-22Si/ZL104 bi-metal

Bi-metal material consisting of spray-formed Al-22 Si and ZL104 is a suitable candidate for applications in internal combustion engines. This research investigated the effects of surface treatment and appropriate gating system on the microstructures and mechanical properties in evaluating the optimal strategy for producing high quality bi-metal materials. The bi-metal materials were prepared using ZL104 gravity casting by different pouring types around the spray-formed Al-22 Si with varied surface treatments. The wettability between Al-22 Si and ZL104 was significantly improved when Zn coating was used to remove the natural oxide layer. This research also obtained the improved interfacial microstructures and interfacial bonding strength for materials when applying the appropriate pouring method. The hardness profiles of Al-22Si/ZL104 bi-metal were consistent with the observed microstructures. The average tensile strength of the bi-metal material with zinc coating is ~42.3 MPa, which is much higher than that with oxide film at ~10 MPa. The process presented is a promising and effective approach for developing materials in the automotive industry.

弯曲载荷下双金属机械复合管内衬层屈曲失效机理

双金属机械复合管是油气田集输管线防腐控制的主要措施之一,而内衬层的失效是制约复合管工程应用的关键难题。为研究双金属机械复合管内衬层屈曲失效机理,建立弯曲载荷下复合管力学模型,研究成型压力、工作内压及复合管结构参数对内衬层失效模式的影响规律。结果表明:增加成型后的残余接触压力有助于提高内衬层的抗屈曲能力;较高的工作内压能够延缓内衬层屈曲时间,减小其褶皱幅值;成型前复合管层间初始间隙减小有利于提高内衬层抗屈曲能力;随着外基管壁厚、内衬管壁厚、复合管内径的增加,内衬管的抗屈曲能力增强。

泡沫镍原位生长普鲁士蓝类似物构筑镍铁双金属氧化物催化剂的氧析出反应性能研究

开发高性能、低成本的氧析出反应(OER)催化剂对促进电解水制氢降低电耗、提高经济性具有重要意义。以导电泡沫镍为基底,采用冰水浴法原位生长镍铁普鲁士蓝类似物,氧化制备了镍铁双金属氧化物催化剂。分别采用X射线衍射、扫描电镜、高分辨率透射电镜和X射线光电子能谱方法对催化剂的物相组成、微观形貌和表面化学状态进行了表征,并采用电化学测试表征了催化剂的OER催化性能。结果表明,当氧化温度为200℃、氧化时间为2 h时,制备的催化剂中镍铁双金属氧化物高度分散在泡沫镍基底上,纳米颗粒最小,平均粒径为71 nm,可暴露的催化反应活性位点多,表现出最优的OER催化性能。该催化剂在1.0 mol/L的KOH电解液中,电流密度为10 mA/cm^(2)时,过电位仅为272 mV,并在电流密度为100 mA/cm^(2)时稳定运行了40 h,表现出优异的OER电化学稳定性。

NiAl催化剂催化5-羟甲基糠醛加氢制备2,5-二羟甲基四氢呋喃

[目的] 5-羟甲基糠醛(HMF)是最重要的生物质基平台化学品之一,可以通过催化加氢途径制备许多高附加值化学品.本文为设计在更加温和的条件下达到高效催化HMF加氢的非贵金属催化剂进行了一系列研究.[方法]通过尿素共沉淀法制备了一种NiAl催化剂,考察了NiAl催化剂催化HMF加氢制备2,5-二羟甲基四氢呋喃(BHMTHF)的性能,并利用X射线衍射(XRD)、氢气程序升温还原(H_(2)-TPR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、氨气程序升温脱附(NH_(3)-TPD)、X射线光电子能谱(XPS)等表征方法系统地研究了不同Ni/Al比、不同煅烧温度和还原温度对催化剂理化性质的影响.[结果] Ni和Al的投料原子比为3∶1,在350℃下煅烧、650℃下还原制备的催化剂Ni_(3)Al-350-650在100℃、氢气压力2.5 MPa的条件下反应1 h,HMF的转化率和BHMTHF产率分别高达99.5%和87.5%.过高的Ni/Al比制备的催化剂比表面积较小,导致暴露的活性位点较少从而降低了催化活性,通过煅烧温度可以调节NiAl催化剂的可还原性.[结论]本研究实现了在温和条件下HMF的高效催化加氢转化.该结果可为用于HMF定向转化的非贵金属催化剂的设计提供参考.

铋基金属有机框架材料的合成及光催化研究进展

铋基金属有机框架(Bi-MOF)材料综合铋基光催化剂和金属有机框架(MOFs)材料的优点,具有极大的应用潜力。本文介绍了Bi-MOF材料常见的制备方法,包括水热/溶剂热法、微波法、共沉淀法、机械化学法和高温退火法等;梳理了Bi-MOF材料作为光催化剂在处理废水、固氮、制氢、还原CO_(2)等方面的最新研究进展,分析了现阶段Bi-MOF材料在光催化方面存在的问题,对Bi-MOF材料在光催化领域的发展方向进行了展望。

Recent update on electrochemical CO_(2)reduction catalyzed by metal sulfide materials

Seeking and developing efficient CO_(2)reduction reaction(CO_(2)RR)electrocatalysts is a hot topic in this era of global warming.Among material candidates for sustainable and cost-effective applications,metal sulfides have attracted attention as promising nature-inspired materials due to multiple adsorption sites which are enhanced by the covalent character of sulfur.This article summarizes the current status regarding the utilization and development of metal sulfide materials as CO_(2)RR electrocatalysts.First,the research background and basic principles of electrochemical CO_(2)RR are introduced.Next,an overview of the main obstacles to developing efficient CO_(2)RR electrocatalysts is presented.The section is followed by a summary of the empirical evidence supporting the application of metal sulfides as CO_(2)RR electrocatalysts beside nature-inspired motivation.The summary of synthesis methods of various metal sulfides is also presented.Furthermore,the paper also highlights the recent works on metal sulfide as efficient CO_(2)RR including the undertaking strategy on the activity enhancement,and finally,discusses the challenges and prospect of metal sulfides-based CO_(2)RR electrocatalysts.Despite recent efforts,metal sulfides remain relatively unexplored as materials for CO_(2)RR electrocatalytic applications.Therefore,this review aims to stimulate novel ideas and research for improved catalyst designs and functionality.

C_(6)^(+)正构烷烃芳构化的研究进展

通过烷烃芳构化可将催化裂化汽油深度脱硫工艺和煤制油工艺中产生的大量低辛烷值饱和直链烷烃转化成芳烃,从而提升油品质量和芳烃产能,是制备芳烃的重要非石油路线,具有显著的社会经济价值。其中,C_(2)-C_5轻烃芳构化技术相对成熟,已进入到工业应用阶段;而针对C_(6)^(+)直链烷烃芳构化,由于反应过程复杂、多种基元反应相互竞争,导致芳烃收率偏低、催化剂易结焦失活。为此,本工作综述了近年来有关C_(6)^(+)正构烷烃芳构化的研究进展,重点讨论了C_(6)^(+)直链烷烃芳构化的反应机理以及单功能及双功能催化体系中金属位点分散度、电子状态及载体的酸性、形貌和孔道结构等对反应性能的影响。

水杨醛衍生物的合成及其离子识别性能研究

两步法合成了水杨醛衍生物(罗丹明6G酰肼缩水杨醛),首先由罗丹明6G和水合肼反应合成罗丹明6G酰肼,再和水杨醛缩合制备席夫碱。并以此为探针L,通过荧光光谱法和紫外-可见吸收光谱法(UV-Vis)研究其对金属阳离子溶液的识别性质。实验结果表明:该探针用UV-Vis法均可识别Cu^(2+),并且不受其他阳离子干扰,紫外光谱识别Cu^(2+)的检测限LOD=9.09×10^(-7)mol/L,Cu^(2+)和探针L的络合比为1∶1。荧光光谱法可识别Bi^(3+),且受其他阳离子干扰较小,荧光光谱识别Bi^(3+)的检测限LOD=2.823×10^(-9)mol/L,Bi^(3+)和探针L的络合比为2∶1。

一件绿色托帕石样品的检测

实验室收到一件黄绿色刻面型爪镶戒指进行检测,商家以橄榄石出售。通过常规的宝石学仪器设备对该试样的折射率、密度、发光特性等进行了检测,为确定其成分和微量元素,利用Nicolet iS5型傅里叶变换红外光谱仪、紫外-可见吸收光谱仪和X射线荧光能谱仪等对该样品开展了研究。结果显示:样品是覆膜托帕石,台面测得折射率为1.619~1.627,亭部及腰部不可测,亭部尖端可见刻面棱处明显的膜脱落现象,亭部有很高的Bi。根据我国国家标准《GB/T 16552—2017》规定,将该样品定名为覆膜托帕石。

基于“金水相生”探讨消渴病痹证从肺肾辨治

基于“金水相生”探讨消渴病痹证从肺肾辨治,将其病因统归于因病和因药两大块。消渴日渐,气血运行失常,阴虚内热,耗伤津液,以致耗伤真阴(肾阴);又可导致血行不畅、瘀阻脉络,合而为痹。肺之宣降功能失司,使四肢百骸、皮毛和脏腑失养,气血不调,脉络失于濡养,瘀阻脉络,或当真阴被耗,水不涵木,虚风暗动,则见阵发肢体麻痹、刺痛等消渴病痹证的症状。部分降糖药物和抗氧化药可引起皮疹、出汗、腹泻,使患者陷入紧张、烦躁、不安等郁症相关不良情绪,使气机不畅,进一步加重消渴病痹证的症状。采用肺朝百脉助心行血而祛瘀、宣肺开鬼门给邪以出路、补先天之本而补五脏,补不足、损有余,使气血畅,身自安。

双花簇状铁锰催化剂活化过一硫酸盐降解MB

该文以金属有机骨架MIL-Fe(100)为模板,经锰掺杂和高温煅烧得到双金属衍生物作为催化剂,高效活化过一硫酸盐(PMS)用于降解亚甲基蓝(MB)染料。采用扫描电子显微镜(SEM)、X射线粉末衍射仪(XRD)、傅里叶变换红外光谱仪(FTIR)和X射线能谱分析(EDS)对Fe_(1)Mn_(2)-400材料的表面晶貌和化学结构进行了表征,证明该催化剂具有特殊的双花簇状形貌。探究得出在Fe/Mn摩尔比为1∶2,催化剂投加量为0.3 g/L,PMS浓度为2 mmol/L的最优条件下,MB的降解率可达92.19%,TOC去除率为50.71%,反应过程符合伪一级动力学(R^(2)>0.9)。通过淬灭实验证明了在Fe1Mn2-400/PMS体系中,SO_(4)^(·-)和·OH均是降解MB的主要活性物种,其中·OH占主导作用。X射线光电子能谱(XPS)反映出铁锰之间的协同作用促进了Fe(Ⅲ)/Fe(Ⅱ)的价态循环,从而提高了PMS的激活效率,实现了MB的高效降解。

基于桥联双β-二亚胺配体的二价稀土配合物的反应性研究

金属羰基自由基配合物是有机合成与转化中重要的活性中间体,但这类配合物有不稳定和易发生偶联的缺点。为了解决这类问题,更好地发挥它的优点,金属中心和配体的的选择尤为重要。本文用桥联双β-二亚胺配体稳定的二价镱配合物L1Yb(L1=[μ-(1,2-CH_(2)CH_(2))][N(Me)CH_(2)CH_(2)NC-(Me)CHC(Me)NDipp]_(2)^(2-),Dipp=2,6-(iPr)_(2)C_(6)H_(3))与1当量二苯甲酮发生氧化还原反应,得到深紫色三价镱二苯甲酮自由基配合物L1YbOC·Ph_(2)(1),通过核磁共振氢谱、元素分析、红外光谱及单晶X-射线衍射对其结构进行了表征,发现该配合物不易发生偶联反应,具备很好的稳定性。

双金属复合管塑性成型有限元模拟

随着高含二氧化碳、硫化氢及元素硫等油气田的相继出现,油管、套管的腐蚀问题越来越突出,并直接影响到油气田的经济开发和安全开采。针对机械复合管塑性成型过程中的力学问题进行了有限元模拟研究,建立了模拟双金属复合管塑性成型的参数化有限元力学模型。通过有限元模拟研究,得出了双金属复合管所需的最小成型压力和成型后内外管间的结合力,分析了双金属复合管在塑性成型过程中内外管的接触压力、径向应力应变等力学特性。计算实例表明,该模型的几何尺寸、材料模型以及加载压力等参数均可以根据计算需要设定,可用于模拟不同材质和不同尺寸的双金属管在塑性成型过程中的力学特性研究。

固体火箭推进剂用燃烧催化剂研究新进展

从纳米燃烧催化剂、含能催化剂和双金属燃烧催化剂三方面综述燃烧催化剂的研究新进展。总结了各类催化剂的特点和发展过程中的技术难题,指出燃烧催化剂的发展方向,如纳米催化剂的团聚抑制和催化机理、含能催化剂能量与感度的统一以及双金属催化剂的结构表征和含能化等。附参考文献55篇。

薄规格双金属复合板剪切强度的测试方法

参照GB/T6396-2008和ASTM A 264设计了薄规格双金属复合板抗剪强度的测试方法及装置,并对薄规格双金属复合板的抗剪强度进行了测试,与现有商品板的抗剪强度进行了对比和分析。结果表明:提出的测试方法简单实用和实验装置操作方便,测量误差小,数据离散度小,精度高,能准确评价薄规格双金属复合板的结合强度,测试结果符合GB/T6396-2008要求。

双金属改性ZSM-5/L复合分子筛的制备及其催化芳构化反应性能

采用分级改性的方法制备Zn-ZSM-5/Pt-L核壳型双金属催化剂,通过改变金属负载量的组配方式对催化剂表面酸性进行调控,利用X射线衍射(XRD)、氮气吸附脱附、氨气程序升温脱附(NH3-TPD)、吡啶吸附-原位傅里叶变换红外光谱(Py-FTIR)等手段进行表征,并以正戊烷为原料对催化剂的轻烃芳构化性能进行评价。结果表明,在复合分子筛核壳结构的基础上,分级引入双金属的改性方式有效地调控了催化剂表面的酸分布以及L/B酸比例,使双金属催化剂更好地发挥L酸和B酸的协同催化作用,当Zn和Pt负载量分别为1.0%和0.6%时所表现出的催化性能最优,其正戊烷芳构化反应的转化率为99.1%、芳烃选择性达到47.2%。