V2.1TiNi0．4Zr0．06Cu0．03M0．10（M=Cr，Co，Fe，Nb，Ta）储氢合金的微结构及电化学性能

采用磁悬浮感应熔炼方法制备了V2.1TiNi0.4Zr0.06Cu0.03M0.10(M=Cr,Co,Fe,Nb,Ta)(M=Cr,Co,Fe,Nb,Ta)储氢电极合金,通过X射线衍射(XRD)、扫描电了显微镜(SEM)、电子衍射能谱(EDS)分析和电化学测试等手段系统研究了添加元素M对合金微结构与电化学性能的影响.结果表明,所有合金均由BCC结构的V基同溶体主相和C14型Laves第二相组成,且第二相沿主相品界形成三维网状分布;Cr、Nb和Ta元素主要分布在合金主相中,而Co和Fe元素主要分布在第二相中.电化学性能测试表明,在V2.1TiNi0.4Zr0.06Cu0.03合金中掺加Cr、Co、Fe、Nb或Ta元素后,虽然会降低最大放电容量,但能有效抑制合金中V和Tj的腐蚀溶出,提高电极充放电循环稳定性;同时还能明显改善合金的高倍率放电性能.相比之下,V2.1TiNi0.4Zr0.06Cu0.03Cr0.10合金具有最佳的综合电化学性能.     

V2.1TiNi0.4Zr0.06Cux（x=0-0.12）储氢合金的微结构及电化学性能

采用磁悬浮感应熔炼方法制备了V2.1TiNi0.4Zr0.06Cux(x=0-0.12)储氢合金,经XRD、SEM、EDS和电化学测试等系统研究了Cu添加量对合金微结构及电化学性能的影响.结果表明,所有合金均由V基固溶体主相和C14型Laves第二相组成,且第二相沿主相晶界形成三维网状分布;合金主相和第二相的晶胞体积均随着Cu含量x的增加而增大.电化学性能测试表明,添加适量(x=0.03-0.06)的Cu可以提高合金的最大放电容量,并对活化性能基本没有影响:而过高的Cu添加量(x≥0.09)会降低合金的放电容量.此外,添加Cu可使合金的高倍率放电性能得到明显改善,充放电循环稳定性有所提高.在所研究的合金样品中,V2.1TiNi0.4Zr0.06Cu0.03合金具有最佳的综合性能.     

V2.1TiNi0.4Zr0.06Cux(x=0-0.12)储氢合金的微结构及电化学性能

采用磁悬浮感应熔炼方法制备了V2.1TiNi0.4Zr0.06Cux (x=0-0.12)储氢合金, 经XRD、SEM、EDS和电化学测试等系统研究了Cu添加量对合金微结构及电化学性能的影响. 结果表明, 所有合金均由V基固溶体主相和C14型Laves第二相组成, 且第二相沿主相晶界形成三维网状分布; 合金主相和第二相的晶胞体积均随着Cu含量x的增加而增大. 电化学性能测试表明, 添加适量(x=0.03-0.06)的Cu可以提高合金的最大放电容量, 并对活化性能基本没有影响; 而过高的Cu添加量(x≥0.09)会降低合金的放电容量. 此外, 添加Cu可使合金的高倍率放电性能得到明显改善, 充放电循环稳定性有所提高. 在所研究的合金样品中, V2.1TiNi0.4Zr0.06Cu0.03合金具有最佳的综合性能.     

V2.1TiNi0.4Zrx(x=0～0.06)储氢电极合金的相结构及电化学性能*

系统研究了V2.1TiNi0.4Zrx(x=0耀0.06)储氢电极合金的相结构及电化学性能. 相结构分析表明, 所有合金均由体心立方(bcc)结构的V 基固溶体主相和第二相组成, 且第二相沿主相晶界形成三维网状分布;其中, 当Zr 含量x 臆0.02时合金的第二相为TiNi基相, 而当Zr含量x达0.04时, 其第二相变为C14型Laves相, 且主相和第二相的晶胞体积均随着x 的增加而增大.电化学性能测试表明, 添加Zr 元素可以改善合金的活化性能和提高最大放电容量; 同时, 随着Zr 含量x 的增大, 合金的高倍率放电性能得到明显提高, 但充放电循环稳定性逐渐降低. 在所研究的合金样品中, V2.1TiNi0.4Zr0.04合金具有相对较好的综合性能.     

Ni添加对Ti0.4Zr0.1V1.1Mn0.5Cr0.1合金的相结构和电化学性能的影响

本文通过XRD、SEM、EDS研究了Ti0.4Zr0.1V1.1Mn0.5Cr0.1Nix(x=0,0.2,0.4,0.6,0.8)合金的相结构和电化学性能.该合金系由BCC结构的V基固溶体主相和六方结构的C14 Laves第二相组成,Ni能够促进第二相的生成,Ni含量的增加导致了各相中的化学组成和晶格参数的变化,并通过电化学方法研究了Ni含量对Ti0.4Zr0.1V1.1Mn0.5Cr0.1合金电极的最大放电容量、自放电性能、高倍率放电性能、循环稳定性能等的影响.     

添加元素对AB2型Laves相合金电化学性能的影响

比较系统地研究了AB2型Laves相合金Zr0.9Ti0.1Ni0.1Mn0.7V0.3M0．1(M=None，Ni．Mn．V．Co．Cr．Al．Fe，Mo．Si．C．Zn，Cu和B)的相结构和电化学性能以及高温和低温放电性能等．结果表明．14种合金均具有六方C14型Laves相的主相晶体结构．同时，含有少量立方Cl5型Laves相和一些由Zr9Ni11及ZrNi组成的非Laves相；添加V和Mn可提高AB2合金的放电容量；添加B和Mn则显著提高了AB2合金的高倍率放电性能和低温放电容量；添加Al，C．Si和Co对合金电极的循环稳定性改善明显；而Mn．Ni．V．Fe．Cu．Mo和B等却不同程度地降低了循环稳定性；添加Si．Mo，V，Cr和Al可明显改善合金电极的自放电性能；添加Si．Cr．V可显著改善AB2合金电极的高温放电性能．讨论了各种添加元素影响合金性能的可能原因．     

Cr对V2.1TiNi0.3贮氢合金结构和电化学性能的影响

研究了Cr添加量对V_2.1TiNi_0.3Cr_x(x=0,0.2,0.4,0.6)贮氢合金的结构和电化学性能的影响。结果表明,所有合金均由V基固溶体主相和TiNi基第二相组成,且第二相呈网状分布在晶界上,部分呈颗粒状分布于合金主相之中。随着Cr含量增大,合金主相的晶胞体积与合金电极的最大放电容量逐渐减小,而循环稳定性逐渐增加,同时合金电极的动力学性能得到改善。在合金中添加Cr使合金电极的活化性能变差,但添加量的进一步增多对其活化性能影响不大。综合考虑,V_2.1TiNi_0.3Cr_0.4合金的电化学性能最好,最大放电容量可达442.20 mAh·g^-1,20次充放电循环后容量保持率达81.91%。     

Cr对V2.1TiNi0.3贮氢合金结构和电化学性能的影响

研究了Cr添加量对V_(2.1)Ti Ni_(0.3)Crx(x=0,0.2,0.4,0.6)贮氢合金的结构和电化学性能的影响。结果表明,所有合金均由V基固溶体主相和Ti Ni基第二相组成,且第二相呈网状分布在晶界上,部分呈颗粒状分布于合金主相之中。随着Cr含量增大,合金主相的晶胞体积与合金电极的最大放电容量逐渐减小,而循环稳定性逐渐增加,同时合金电极的动力学性能得到改善。在合金中添加Cr使合金电极的活化性能变差,但添加量的进一步增多对其活化性能影响不大。综合考虑,V_(2.1)Ti Ni_(0.3)Cr_(0.4)合金的电化学性能最好,最大放电容量可达442.20 m Ah·g~(-1),20次充放电循环后容量保持率达81.91%。     

VCe0.95M0.05 (M=Cu, Co, Mn, Fe或Cr) 复合氧化物的结构和氧化还原性能

采用溶胶 凝胶法制备VCe和VCe0.95M0.05(M=Cu,Co,Mn,Fe或Cr)复合氧化物。用XRD,拉曼光谱,XPS和TPR技术对结构和氧化还原性能进行表征。所有样品的主要物相是四方相的VCeO4。当Fe,Mn,Cu或Co取代部分Ce导致形成少量CeO2或单斜相的VCeO4。XPS结果表明VCe0.95Co0.05,VCe0.95Mn0.05,VCe0.95Cr0.05和VCe0.95Fe0.05复合氧化物中V的价态是+5+δ(δ<1)高于VCe,而VCe0.95Cu0.05相反,V的价态是+5-δ低于VCe。Fe,Co,Cr或Mn能促进VCeO4中V5+的还原,而Cu抑制VCeO4中V5+的还原。     

Ti0.10Zr0.15V0.35Cr0.10Ni0.30+5wt% LaNi5复合储氢合金的电化学性能与协同效应

为了改善钛钒基固溶体合金的电化学性能,利用两步电弧熔炼法制备复合储氢合金Ti0.10Zr0.15V0.35Cr0.10Ni0.30+5wt%LaNi5,X-射线衍射(XRD)和场发射扫描电镜-能谱(FESEM-EDS)显示:复合储氢合金的主相是体心立方结构的钒基固溶体相和六方结构的C14 Laves相,复合过程中生成了第二相。电化学测试结果表明:复合合金电极的P-C-T特征、活化性能、最大放电容量、循环稳定性、低温放电性能和动力学特性均较母体合金有显著改善。复合合金电极的活化周期数为5,最大放电容量为353.9 mAh.g-1,233 K时低温放电能力为50.26%。该复合合金电极的最大储氢容量、平台压、电荷转移电阻和交换电流密度均存在协同效应;在任意循环、在高/低温下以及在高倍率放电过程中,该复合合金电极的放电容量均存在协同效应。     

熔体旋淬合金Zr_(0.9)Ti_(0.1)(Ni,Co,Mn,V)_(2.1)的微结构与电化学性能

对比研究了熔体旋淬和常规熔铸合金Zr0 .9Ti0 .1(Ni,Co ,Mn ,V) 2 .1的微结构和电化学性能 .XRD分析表明 :熔体旋淬合金在退火前后的晶体结构和铸态合金一样 ,均为面心立方结构 ,由LaveC15相组成 ;并且随旋淬速度的增加 ,旋淬合金中的非晶成分越多 .电化学测试表明 :旋淬合金有较好的活化性能 ,但其最大放电容量较低 ,小于 2 80mAh/g ;而退火后的旋淬合金需经 30次循环才能完全活化 ,其最大放电容量皆为 34 0mAh/g左右 ,高于铸态合金和退火前的旋淬合金 ;在电流密度为 30 0mA/g下进行充放电循环 ,发现退火后的旋淬合金循环稳定性明显高于铸态合金电极 ,并且随旋淬速度的增加 ,循环稳定性越好 ,经过 80 0次循环后 ,退火后的 4 0m/s合金容量保持率高达 85 % ,容量衰减率只有 6.9%     

Combinatorial screening of PtTiMe ternary alloys for oxygen electroreduction

The catalytic oxygen electroreduction properties of PtTiMe (Me = Co, Cr, Cu, Fe, Mn, Mo, Ni, Pd, Ta, V, W and Zr) ternary alloys were studied using an in-house developed thin film based combinatorial high throughput method. Libraries containing discrete alloy compositions were fabricated by plasma co-sputtering and the resulting alloys were electrochemically screened by the hydrodynamic rotating disk electrode technique. Candidate catalysts were identified by comparing the activity-stability-composition relationships between the platinum titanium alloys and pure platinum standard. Among the PtTiMe alloys studied, PtTiNi, PtTiCu and PtTiV, respectively, displayed the highest catalytic oxygen electroreduction activities with a tenfold, an eightfold and a sixfold enhancement as compared to the pure platinum standard and good chemical stabilities.     

Metal oxide promoted TiO2 catalysts for photo-assisted selective catalytic reduction of NO with NH3

The photo-assisted selective catalytic reduction (SCR) of NO with NH₃ (Photo-SCR) was performed over TiO₂ modified by supporting 1 wt% of various transition metal (V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ta or W) oxides aiming at the improvement of the photo-SCR activity. The addition of Nb, Mo or W oxide to TiO₂ was found to enhance the photo-SCR activity. We have reported that the amount of acid sites on TiO₂ is one of the key factors to the photo-SCR activity. The increase in the activity depends on the enhancement of acidity of catalyst by the addition of Nb, Mo or W oxide. In contrast, the addition of V, Cr, Mn, Fe, Co, Ni or Cu oxide to TiO₂ lowered the photo-SCR activity, although addition of metal cations also changed the acidity of TiO₂. We guess that the reduction of the activity was caused by two reasons; the first is that the sites newly formed on these transition metal oxides is not photoactive and the second is that TiO₂ supporting V, Cr, Mn, Fe, Co, Ni or Cu oxides had low stabilities under the reaction conditions, i.e., the chemical state of the cations changed during the reaction. Therefore, we concluded that the increase in the acid sites that are active sites for photo-SCR and the stability of the catalysts are important for the photo-SCR.     

一种快速凝固AB2型储氢合金的球磨改性

Zr0. 9Ti0. 1 (Ni0.57V0.1Mn0. 28Co0. 05 )2.1 alloy was prepared by melt-spinning and ball-milled with Co3Mo additive to improve its kinetic characteristics. It was shown that after 2 h milling the alloy exhibited a much improved activation performance as well as electrochemical capacity. Electrochemical impedance experiments also showed that ball-milling of the alloy with Co3Mo could improve the surface activity to a great extent. This can be attributed to the catalytic effect of Co3Mo, which had a much closer contact with the alloy powder after ball-milling, on hydrogen oxidation. However, long time milling could decrease the capacity gradually due to the further amorphization of the alloy. The experimental results also showed that the alloy ball-milled with electrochemically catalytic material such as Co3Mo exhibited a better activity than those milled without any additives or with a metal powder such as Cu acting only as a conductor.     

Extractive-spectrophotometric determination of molybdenum with 4-unsubstituted-5-pyrazolones

A fairly sensitive and selective method for rapid determination of tracer amounts of molybdenum(V) as mixed-ligand complexes with thiocyanate and 4-unsubstituted-5-pyrazolones is described. The red complexes are extractable into chloroform from 1-5M hydrochloric or perchloric acid or 1-3M sulphuric arid media. The molar absorptivities are in the range 1.72-2.15 x 10(4)l.mole(-1).cm(-1) at 455 nm (lambda(max)). The method has been applied to the estimation of molybdenum in various synthetic and alloy-steel samples. In presence of excess of the reagent, Cu(II), Co(II), Mn(II), Fe(II), Fe(III), Al(III), Cr(III), Cr(VI), Ti(III), Ti(IV), Zr(IV), Hf(IV), V(III), V(IV), V(V), Nb(V), Ta(V), W(VI) and U(VI) do not interfere.