钛合金表面掺金属类金刚石薄膜的摩擦磨损性能研究

采用阳极层流型矩形气体离子源结合非平衡磁控溅射法在钛合金基体表面制备掺金属类金刚石(Me-DLC)薄膜,通过X射线光电子能谱仪、俄歇微探针、表面形貌仪及扫描电子显微镜等对薄膜结构进行表征,用SRV型摩擦磨损试验机评价其摩擦磨损性能.结果表明,类金刚石薄膜可以提高钛合金基体的承载能力和硬度,对基体材料起到有效的耐磨减摩作用,掺钨类金刚石薄膜的硬度及膜/基结合强度较高,具有良好的耐磨减摩性能,且在膜层承载能力范围内,载荷越高,DLC梯度薄膜的摩擦系数越小.

环氧树脂掺金属粉末嵌入式FBG封装技术研究

针对光纤光栅(FBG)与被测金属构件可靠连接问题,提出环氧树脂掺金属粉末嵌入式封装技术,阐明了该封装工艺,采用纯弯曲梁对裸光纤光栅和封装后的光纤光栅分别进行应变实验,结果表明,经环氧树脂掺金属粉末封装后的光纤光栅传感器应变灵敏度是裸光纤光栅的1.3倍,达到1.53pm/με,具有很好的重复性,该方法提高了嵌入光纤光栅后被测金属构件的机械强度。

掺Ni^(2+)、Cu^(2+)、Zn^(2+)金属离子聚合物对BSA的吸附性能研究

本文以丙烯酰胺作为功能单体、乙二醇二甲基丙烯酸酯作为交联剂、偶氮二异丁腈作为引发剂作为反应体系,分别向该体系中加入一定量的醋酸镍、醋酸铜和氯化锌以获得对蛋白质具有亲和力的活性位点,采用方便易行的热引发本体聚合方法制备了对蛋白质具有特异性吸附的三种掺金属离子聚合物,并通过透射电子显微镜和马尔文激光粒度仪对其进行了表征。随后用牛血清白蛋白(BSA)为蛋白质模型,考察了这三种掺金属离子聚合物对蛋白质的吸附性能。结果表明,这三种掺金属离子聚合物对蛋白质的吸附是由聚合物中的金属离子含量决定的,属于特异性的亲和吸附,且掺铜离子聚合物的吸附性能最强。

基于金属掺杂ITO透明导电层的紫外LED制备

为降低ITO薄膜对紫外波段的光吸收,制备低电压高功率的紫外LED,研究了一种基于金属掺杂ITO透明导电层的365nm紫外LED的制备工艺。利用1cm厚的石英片生长了不同厚度ITO薄膜以及在ITO上掺杂不同金属的新型薄膜,并研究了在不同的退火条件下这种薄膜的电阻和透过率,分析了掺杂金属ITO薄膜的带隙变化。将这种掺杂的ITO薄膜生长在365nm外延片上并完成电极生长,制备成14mil×28mil的正装LED芯片。利用电致发光(EL)设备对LED光电性能进行测试并对比。实验结果表明:掺Al金属的ITO薄膜能够相对ITO薄膜的带隙提高0.15eV。在600℃退火后,方块电阻降低6.2Ω/□,透过率在356nm处达到90.8%。在120mA注入电流下,365nmLED的电压降低0.3V,功率提高14.7%。ITO薄膜掺金属能够影响薄膜带隙,改变紫光LED光电性能。

掺过渡金属钴的非晶硅薄膜的ESR和光电特性的研究

本文对用电子束蒸发法制备的a-Si:Co薄膜的ESR和光学特性进行了研究.对样品的ESR信号、光学带隙和室温电导率随杂质浓度的变化关系进行了测量.结果表明,Co原子在a-Si:Co薄膜中形成受主中心,并伴随着对悬挂键的补偿;当杂质浓度小于3％时,光学带隙、自旋态密度和峰峰宽度基本不变,当杂质浓度大于3％时,随着Co含量的增加,光学带隙、自旋态密度减小,室温电导率和峰峰宽增大.本文对上述结果进行了分析和讨论.

非金属元素N-S共掺杂SnO_(2)电性能第一性原理研究

基于密度泛函理论第一性原理和平面波超软赝势法,采用广义梯度近似法构建了非金属元素N、S单掺,以及N-S共掺的SnO_(2)的超晶胞,分析这三类超晶胞的焓变、能带图、态密度、电荷布局以及导电率。理论结果表明,N和S单掺杂以及N-S共掺杂都可以使SnO_(2)的带隙变小,能带紧密,而N-S双掺杂的效果最好。其中,在价带中部S原子和N原子的掺入均引入了新能级,S原子的轨道和N原子的轨道与Sn轨道发生杂化,使得电子转移加剧。价带顶被S原子的3p轨道和N原子,2p轨道占据,会有更多的空穴载流子,价带顶部向上移动。N、S原子共掺杂时,轨道共同杂化,效果最明显,电性能变好。

三氧化钨氢还原时碱金属元素引起的钨粉超常规粗化现象

研究了锂、钠、钾在氢还原二氧化钨时引起产物钨粉超常规粗化现象的特点、差别。锂是使钨粉晶粒长大的最佳掺杂元素，当它的掺入量≥400×10－6、还原温度≥1000℃时，可以获得FSSS粒度达100μp的特粗结晶钨粉。

Single atom doping induced charge-specific distribution of Cu1-TiO_(2)for selective aniline oxidation via a new mechanism

Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging endeavor.Meanwhile,identifying the active site also represents a significant obstacle,primarily due to the intricate electronic environment of single atom site doped metal oxide.Herein,a single atom Cu doped TiO_(2)catalyst(Cu_(1)-TiO_(2))is prepared via a simple“colloid-acid treatment”strategy,which switches aniline oxidation selectivity of TiO_(2)from azoxybenzene to nitrosobenzene,without using additives or changing solvent,while other metal or nonmetal doped TiO_(2)did not possess.Comprehensive mechanistic investigations and DFT calculations unveil that Ti-O active site is responsible for triggering the aniline to form a new PhNOH intermediate,two PhNOH condense to azoxybenzene over TiO_(2)catalyst.As for Cu_(1)-TiO_(2),the charge-specific distribution between the isolated Cu and TiO_(2)generates unique Cu_(1)-O-Ti hybridization structure with nine catalytic active sites,eight of them make PhNOH take place spontaneous dissociation to produce nitrosobenzene.This work not only unveils a new mechanistic pathway featuring the PhNOH intermediate in aniline oxidation for the first time but also presents a novel approach for constructing single-atom doped metal oxides and exploring their intricate active sites.

玻璃中植入金属离子的特性及应用前景

在绝缘体中植入离子后可能由于辐射损伤、相分离或化合物的形成而引起折射系数的变化。结果有可能形成在光电子学领域有很大应用价值的光波导。目前，金属（如银、铜、金、铅等）离子的植入已证明有可能在玻璃基体的表面薄层中形成小半径的胶粒。这种粒子显示出一种电子等离子体子共振，这种共振取决于植入金属的光学常数和玻璃基质的折射系数。这种胶体的非线性光学性能，特别是Ｋｅｒｒ光学磁化率的增大暗示人们。

金属掺杂ITO透明导电薄膜的制备及应用

研究制备了一种新型金属掺杂ITO透明导电薄膜。通过研究掺杂不同的金属及不同的金属厚度,对比在500℃和600℃退火条件下的透过率和方块电阻变化,并利用这种掺杂的ITO薄膜制备成14mil×28mil正装395nm UV LED芯片。利用电致发光(EL)设备对LED光电性能进行测试以及对比。实验结果表明:掺3nm金属Al和Ti的ITO薄膜在600℃退火后方块电阻最大降低6.2Ω/,透过率在395nm处最大达91.2%。在120mA注入电流下,395nmLED电压降低0.5V,功率提升19.7%。ITO薄膜掺杂金属能够影响薄膜性能,提升紫光LED光电性能。

First-Principles Study of Magnetism in Transition Metal Doped Na0.5Bi0.5TiO3 System

The origins of magnetism in transition-metal doped Na0.5Bi0.5TiO3 system are investigated by ab initio calculations. The calculated results indicate that a transition-metal atom sub- stitution for a Ti atom produces magnetic moments, which are due to the spin-polarization of transition-metal 3d electrons. The characteristics of exchange coupling are also calculated, which shows that in Cr-/Mn-/Fe-/Co- doped Na0.5Bi0.5TiO3 system, the antiferromagnetic coupling is favorable. The results can successfully explain the experimental phenomenon that, in Mn-/Fe- doped Nao.sBio.sTiO3 system, the ferromagnetism disappears at low tem- perature and the paramagnetic component becomes stronger with the increase of doping concentration of Mn/Fe/Co ions. Unexpectedly, we find the Na0.5Bi0.5Ti0.67V0.33iO3 sys- tem with ferromagnetic coupling is favorable and produces a magnetic moment of 2.00 P-B, which indicates that low temperature ferromagnetism materials could be made by intro- ducing V atoms in Na0.5Bi0.5TiO3. This may be a new way to produce low temperature multiferroic materials.

Influence of the metal sites of M-N-C(M=Co, Fe, Mn) catalysts derived from metalloporphyrins in ethylbenzene oxidation

Transition metal catalysts M-N-C（M = Co,Fe,Mn） were synthesized by a template-free method by heating meso-tetraphenyl porphyrins（i.e.CoTPP,FeTPPCl,MnTPPCl） precursors.The catalysts were characterized by N2 adsorption-desorption,thermogravimetry,high-resolution transmission electron microscopy,and Raman and X-ray photoelectron spectroscopy.The selective oxidation of ethylbenzene with molecular oxygen under a solvent-free condition was carried out to explore the catalytic performance of the M-N-Cs,which exhibited different catalytic performance.That was ascribed to the difference in M（Co,Fe,Mn） and different graphitization degree forming during the heating process,in which M（Co,Fe,Mn） might have different catalytic activity on the formation of the M-N-C catalyst.All the M-N-C composites had remarkable recyclability in the selective oxidation of ethylbenzene.

Interactions of Anionic and Neutral Serine with Pure and Metal-doped Graphene Studied by Density Functional Theory

We present a theoretical study of interactions of anionic and neutral serine （Ser） on pure or metal-doped graphene surfaces using density functional theory calculations. Interactions of both types of Ser with the pure graphene surface show weak non-covalent interactions due to the formation of-COOH…π, -COO^-…π, and -OH…π interactions. On metal- doped graphene, covalent interactions to the surface dominate, due to the formation of strong metal-O and O-metal-O interactions. Furthermore, the doped Fe, Cr, Mn, A1, or Ti enhances the ability of graphene to attract both types of Ser by a combination of the adsorption energy, the density of states, the Mulliken atomic charges, and differences of electron density. At the same time, the interaction strengths of anionic Ser on various graphene surfaces are stronger than those of neutral Ser. These results provide useful insights for the rational design and development of graphene-based sensors for the two forms of Ser by introducing appropriate doped atoms. Ti and Fe are suggested to be the best choices among all doped atoms for the anionic Ser and neutral Ser, respectively.

Transition Metal Substitutions Induce Ferromagnetism in Bi2Te3

The possibilities of magnetism induced by transition-metal atoms substitution in Bi2Te3 system are investigated by ab initio calculations. The calculated results indicate that a transition-metal atom substitution for a Bi atom produces magnetic moments, which are due to the spin-polarization of transition-metal 3d electrons. The values of magnetic moments are 0.92, 1.97, 2.97, 4.04, and 4.98 μB for 4% Ti-, V-, Cr-, Mn- and Fe-doped Bi2Te3 re- spectively. When substituting two transition-metal atoms, the characteristics of exchanging couple depend upon the distributions of the Bi atoms substituted. When two transition- metal atoms substituting for Bi atoms locate at the sites of Bil and Bi5, with the distance of 11.52A, the Bi1.84TM0.16Te3 system is energetically most stable and exhibits ferromagnetic coupling.

Metal-doped Mo2C(metal=Fe,Co,Ni,Cu)as catalysts on TiO2 for photocatalytic hydrogen evolution in neutral solution

The neutral hydrogen evolution reaction(HER)is vital in the chemical industry,and its efficiency depends on the interior character of the catalyst.Herein,work function(WF)engineering is introduced via 3d metal(Fe,Co,Ni,and Cu)doping for modulating the Fermi energy level of Mo2C.The defective energy level facilitates the free water molecule adsorption and,subsequently,promotes the neutral HER efficiency.Specifically,at a current density of 10 mA/cm2,Cu-Mo2C exhibits the best HER performance with an overpotential of 78 mV,followed by Ni-Mo2C,Co-Mo2C,Fe-Mo2C,and bare Mo2C with 90,95,100,and 173 mV,respectively,and the corresponding Tafel slope values are 40,43,42,56,and 102 mV/dec.The modified WF can also lead to an enhanced photocatalytic efficiency owing to the lowered Schottky barrier and excellent carrier transition across the electrocatalyst–solution interface.When coupling the metal-doped Mo2C samples with TiO2,enhanced photocatalytic neutral HER rates are obtained in comparison to the case with bare TiO2.Typically,the HER rates are 521,404,275,224,147,and 112μmol/h for Cu,Ni,Co,Fe,bare Mo2C,and bare TiO2,respectively.Time-resolved photoluminescence spectroscopy(TRPS)and ultrafast transient absorption(TA)measurements are carried out to confirm the recombination and migration of the photogenerated carriers.The fittedτvalues from the TRPS curves are 22.6,20.5,10.1,4.7,4.0,2.5,and 1.9 ns for TiO2,TiO2-Mo2C,TiO2-Fe-Mo2C,TiO2-Fe-Mo2C,TiO2-Fe-Mo2C,TiO2-Fe-Mo2C,and TiO2-Pt,respectively.Additionally,the fittedτvalues from the TA results are 31,73,and 105 ps for the TiO2-Mo2C,TiO2-Cu-Mo2C,and TiO2-Pt samples,respectively.This work provides in-depth insights into the WF modulation of an electrocatalyst for improving the HER performance.

A comparison study of alkali metal-doped g-C_3N_4 for visible-light photocatalytic hydrogen evolution

Photocatalytic hydrogen production based on semiconductor photocatalysts has been considered as one of the most promising strategies to resolve the global energy shortage.Graphitic carbon nitride(g‐C3N4)has been a star visible‐light photocatalyst in this field due to its various advantages.However,pristine g‐C3N4usually exhibits limited activity.Herein,to enhance the performance of g‐C3N4,alkali metal ion(Li+,Na+,or K+)‐doped g‐C3N4are prepared via facile high‐temperature treatment.The prepared samples are characterized and analyzed using the technique of XRD,ICP‐AES,SEM,UV‐vis DRS,BET,XPS,PL,TRPL,photoelectrochemical measurements,photocatalytic tests,etc.The resultant doped photocatalysts show enhanced visible‐light photocatalytic activities for hydrogen production,benefiting from the increased specific surface areas(which provide more active sites),decreased band gaps for extended visible‐light absorption,and improved electronic structures for efficient charge transfer.In particular,because of the optimal tuning of both microstructure and electronic structure,the Na‐doped g‐C3N4shows the most effective utilization of photogenerated electrons during the water reduction process.As a result,the highest photocatalytic performance is achieved over the Na‐doped g‐C3N4photocatalyst(18.7?mol/h),3.7times that of pristine g‐C3N4(5.0?mol/h).This work gives a systematic study for the understanding of doping effect of alkali metals in semiconductor photocatalysis.

Simple synthesis of nitrogen‐doped carbon spheres as a highly efficient metal‐free electrocatalyst for the oxygen reduction reaction

In the present work, nitrogen‐doped carbon spheres were synthesized through a simple hydro‐thermal treatment using glucose and melamine as inexpensive carbon and nitrogen sources, re‐spectively. The ratio of melamine to glucose and annealing temperature were optimized. The final optimal sample exhibited a catalytic activity for the oxygen reduction reaction（ORR） that was supe‐rior than that of commercial 20%Pt/C in 0.1 mol/L KOH. It revealed an onset potential of –22.6 mV and a half‐wave potential of –133.6 mV （vs. Ag/AgCl）, which are 7.2 and 5.9 mV more positive than those of the 20%Pt/C catalyst, respectively, as well as a limiting current density of 4.6 mA/cm^2, which is 0.2 mA/cm^2 higher than that of the 20%Pt/C catalyst. The catalyst also exhibited higher stability and superior durability against methanol than 20%Pt/C. Moreover, ORRs on this catalyst proceed through a more effective 4 e^– path. The above mentioned superiority of the as‐prepared catalyst makes it promising for fuel cells.

Doping-induced metal–N active sites and bandgap engineering in graphitic carbon nitride for enhancing photocatalytic H_(2 )evolution performance

Durable and inexpensive graphitic carbon nitride(g-C_(3)N_(4))demonstrates great potential for achieving efficient photocatalytic hydrogen evolution reduction(HER).To further improve its activity,g-C_(3)N_(4)was subjected to atomic-level structural engineering by doping with transition metals(M=Fe,Co,or Ni),which simultaneously induced the formation of metal-N active sites in the g-C_(3)N_(4)framework and modulated the bandgap of g-C_(3)N_(4).Experiments and density functional theory calculations further verified that the as-formed metal-N bonds in M-doped g-C_(3)N_(4)acted as an"electron transfer bridge",where the migration of photo-generated electrons along the bridge enhanced the efficiency of separation of the photogenerated charges,and the optimized bandgap of g-C_(3)N_(4)afforded stronger reduction ability and wider light absorption.As a result,doping with either Fe,Co,or Ni had a positive effect on the HER activity,where Co-doped g-C_(3)N_(4)exhibited the highest performance.The findings illustrate that this atomic-level structural engineering could efficiently improve the HER activity and inspire the design of powerful photocatalysts.

High activity and durability of carbon-supported core-shell PtPx@Pt/C catalyst for oxygen reduction reaction

Alloying Pt with transition metals can significantly improve the catalytic properties for the oxygen reduction reaction(ORR).However,the application of Pt-transition metal alloys in fuel cells is largely limited by poor long-term durability because transition metals can easily leach.In this study,we developed a nonmetallic doping approach and prepared a P-doped Pt catalyst with excellent durability for the ORR.Carbon-supported core-shell nanoparticles with a P-doped Pt core and Pt shell(denoted as PtPx@Pt/C)were synthesized via heat-treatment phosphorization of commercial Pt/C,followed by acid etching.Compositional analysis using electron energy loss spectroscopy and X-ray photoelectron spectroscopy clearly demonstrated that Pt was enriched in the near-surface region(approximately 1 nm)of the carbon-supported core-shell nanoparticles.Owning to P doping,the ORR specific activity and mass activity of the PtP_(1.4)@Pt/C catalyst were as high as 0.62 mA cm^(–2)and 0.31 mAμgPt–^(1),respectively,at 0.90 V,and they were enhanced by 2.8 and 2.1 times,respectively,in comparison with the Pt/C catalyst.More importantly,PtP_(1.4)@Pt/C exhibited superior stability with negligible mass activity loss(6%after 30000 potential cycles and 25%after 90000 potential cycles),while Pt/C lost 46%mass activity after 30000 potential cycles.The high ORR activity and durability were mainly attributed to the core-shell nanostructure,the electronic structure effect,and the resistance of Pt nanoparticles against aggregation,which originated from the enhanced ability of the PtP_(1.4)@Pt to anchor to the carbon support.This study provides a new approach for constructing nonmetal-doped Pt-based catalysts with excellent activity and durability for the ORR.