N-Fe共掺杂BiVO_4的制备及其光催化活性的研究

采用溶胶凝胶法制备了N和Fe共掺杂的Bi VO4可见光光催化剂,并用X射线衍射(XRD)、比表面积测试(BET)和紫外-可见漫反射谱(UV-Vis DRS)对其进行了表征.结果显示,N-Fe共掺杂对Bi VO4晶型没有产生影响,掺杂前后均为单斜晶系,但晶粒粒径有所减小,BET比表面积相对增大.由UV-Vis可知,N-Fe共掺杂的Bi VO4的吸光强度明显增强,禁带宽度变窄.以可见光降解甲基橙(MO)考察催化剂的光催化活性,N-Fe共掺杂的Bi VO4对MO的降解速率明显高于纯Bi VO4,证明N-Fe共掺杂产生的协同效应提高了Bi VO4在可见光照射下的光催化活性.     

氮硼掺杂菌糠炭：蜂窝结构用于电极材料

绿色可再生、储量丰富且成本低廉的农林废弃物在能源转化利用领域具有重要位置。本文利用中国北方最常见的农林废弃物菌糠为原料,分别以氢氧化钾、硼酸铵为活化剂和掺杂剂,通过简单的高温煅烧法制备了具有蜂窝结构的氮硼双掺杂菌糠炭（NBFC）。NBFC的微观形貌和物理结构表征结果显示：NBFC-3为表面粗糙的蜂窝状多孔材料,孔径集中在2nm左右,比表面积高达2968.48m²/g,具有相互连接的微介孔网络结构。电化学性能测试结果表明：当电流密度为0.5A/g时,NBFC-3的比电容高达297.2F/g。即使当电流密度增加到10A/g后,比电容仍可达218.5F/g,在循环5000圈后（电流密度为5A/g）,比电容保持率为94.5%,展现了良好的倍率性能和显著的电化学稳定性。综上,NBFC是一种极有潜力的电化学储能材料。该研究也为农林废弃物菌糠的高效利用提供了新思路。     

LiNi0．85Co0．10Al0．05O2正极材料合成及表征

以LiOH·H2O,Ni2O3,Co2O3和Al(OH)3为原料,采用固相反应法合成Co-Al共掺入LiNiO2的化合物LiNi0.85Co0.10Al0.05O2,由TG-DTA,XRD,SEM,DSC和电化学测试表征材料.结果表明,该材料首次放电容量达186.2mAh/g(3.0 V～4.3 V,18 mA/g),10次循环之后,容量还有180.1 mAh/g,容量保持率为96.7%;与未掺杂的LiNiO2相比,该材料显示出良好的循环性能,且热稳定性也有所提高,是一种很有应用前景的锂离子电池正极材料.     

Low temperature thermoluminescence properties of Eu and R doped CaAl2O4

The thermoluminescence (TL) of calcium aluminate persistent luminescence materials doped with Eu²⁺ and co-doped with R³⁺ ions were studied between 20 and 325 K. The basic material, CaAl₂O₄:Eu²⁺, showed three TL bands between 150 and 300 K in the glow curve. Changing the R³⁺ co-dopant to the adjacent element in the rare earth series affects significantly the thermoluminescence intensity and even the position of the glow curve maximum. The physical effect seemed to be removing the traps since the La³⁺, Y³⁺, and Lu³⁺ ions suppressed the thermoluminescence. The Pr³⁺, Ho³⁺, and Dy³⁺ co-doping enhanced mainly the low temperature traps and these materials have an intense but relatively short persistent luminescence at room temperature. The Nd³⁺ and Tm³⁺ ions enhanced the TL bands close to room temperature and are thus the most suitable co-dopants to induce intense and long persistent luminescence. The quenching of the thermoluminescence by Sm³⁺ was concluded to be due to the presence of Sm²⁺ that removes totally the traps.     

Synthesis and characterization of LiNi0.95-xCoxAl0.05O2 for lithium-ion batteries

Samples of LiNi0.95-xCoxAl0.05O2 （x = 0.10 and 0.15） and LiNiO2, synthesized by the solid-state reaction at 725℃ for 24 h from LiOH-H2O, Ni2O3, Co2O3, and AI（OH）3 under an oxygen stream, were characterized by TG-DTA, XRD, SEM, and electrochemical tests. Simultaneous doping of cobalt and aluminum at the Ni-site in LiNiO2 was tried to improve the cathode performance for lithium-ion batteries. The results showed that co-doping （especially, 5 at.% A1 and 10 at.% Co） definitely had a large beneficial effect in increasing the capacity （186.2 mA.h/g of the first discharge capacity for LiNio.s.42OoaoAlo.0502） and cycling behavior （180.1 mA-h/g after 10 cycles for LiNio.85CooaoAlo.osO2） compared with 180.7 mA.h/g of the first discharge capacity and 157.7 mA.h/g of the tenth discharge capacity for LiNiO2, respectively. Differen- tial capacity versus voltage curves showed that the co-doped LiNio.95_xCoxmlo.osO2 had less intensity of the phase transitions than the pristine LiNiO2.     

铁铕共掺杂的TiO_2空心微球的制备及光催化活性

通过溶胶-凝胶法制备铁铕共掺杂的TiO_2(Fe~(3+)-Eu~(3+)/TiO_2)空心微球,采用XRD、TEM、BET和XPS等对样品进行表征,以亚甲基蓝(MB)的光催化降解为目标反应,评价其光催化活性。结果表明:SiO_2微球表面均匀地包覆了1层TiO_2,超声有利于提高SiO_2@TiO_2复合微球间的分散性,同时也发现煅烧前对SiO_2@TiO_2复合微球进行研磨处理后所得的Fe~(3+)-Eu~(3+)/TiO_2空心微球部分塌陷,而未研磨和煅烧后研磨所得Fe~(3+)-Eu~(3+)/TiO_2空心微球完整性较好。XRD和BET分析表明,Fe~(3+)-Eu~(3+)/TiO_2空心微球为锐钛矿且具有良好的介孔结构,铁铕共掺杂在TiO_2空心微球中产生协同作用,使Fe3+-Eu3+/TiO2空心微球的粒径进一步减小,比表面积增大。当Fe~(3+)的掺杂量为1.0%、Eu~(3+)的掺杂量为0.5%时,Fe~(3+)-Eu~(3+)/TiO_2空心微球的光催化活性最高。     

射频输入功率对DLC∶F∶Si薄膜结构和附着特性的调制机理

以SiC陶瓷靶为靶材,Ar和CHF_3为源气体,采用反应磁控溅射法在双面抛光的316L不锈钢基片上制备出了系列Si和F共掺杂的DLC∶F∶Si薄膜。研究了射频输入功率对薄膜的附着力、硬度和表面接触角的影响。结果表明,选取适当的输入功率(180W左右)可以制备出附着力达11N的DLC∶F∶Si薄膜。通过拉曼和红外光谱分析以及样品粗糙度分析,作者提出了输入功率对DLC∶F∶Si薄膜结构和特性调制的机理,即输入功率直接影响SiC靶的溅射产额、空间Ar~+的能量以及CHF_3的分解程度,继而影响空间Si、C、-CF、-CF_2,特别是F~*等基团的能量和浓度,调制薄膜中F含量以及Si-C键含量和C网络的关联度。Si-C、C=C键的增加有助于薄膜附着力的明显改善,F含量的减少则会导致薄膜的疏水性能有所下降。     

S,Fe共掺杂纳米TiO_2的制备及其光催化性能

以水热法制得了S,Fe共掺杂的纳米TiO2光催化剂(TiO2-S-Fe),XRD分析表明,其为锐钛矿晶型,S,Fe掺杂能抑制TiO2粒径的生长;UV-vis漫反射表明,TiO2-S-Fe对可见光吸收增强,吸收带边明显红移;XPS显示S,Fe共掺杂,使得TiO2表面羟基氧含量提高,从而提高催化剂活性;可见光降解甲基橙溶液结果表明,共掺杂样品光催化效果优于单掺样品,S和Fe共掺杂对提高TiO2可见光活性具有协同效应。当Fe3+∶S∶Ti(摩尔比)=0.005∶1∶1,180℃下水热反应3 h时,制得的TiO2-S-Fe可见光催化活性比纯TiO2的活性提高了约10倍。     

Fabrication of Er3+/Pr3+ Co-doped soda-lime glass thin films using RF magnetron sputtering method and optical property characterization

Er^3+/Pr³⁺ co-doped soda-lime glass thin films have been fabricated using RF magnetron sputtering method and their structural and optical properties have been studied. Deposition rate, crystallinity, and composition of glass thin films were investigated by scanning electron microscopy, transmission electron microscopy, and electron probe micro area analysis. Refractive index, birefringence and binding characteristics have been investigated using a prism coupler and X-ray photoelectron spectroscopy. Er³⁺/Pr³⁺ co-doped soda lime glass thin films were prepared by changing substrate temperature (room temp. ∼550^∘C), RF power (90 W–130 W), and Ar/O₂ gas flow ratio at processing pressure of 4 mTorr. Glass thin films could be obtained at the optimized processing condition at 350^∘C, RF power of 130 W, and gas flow of Ar:O₂ = 40:0 with maximum deposition rate of 1.6 μm/h. Refractive index and birefringence increased from 1.5614 to 1.5838 and from 0.000154 to 0.000552, respectively, as the content of Pr³⁺ increased. Binding energy of Pr3d also increased as the content of Pr³⁺ increased.     

Morphological influence of graphitic carbon nanofibers by N–F dual-doping on Pt electrocatalytic activity and stability for oxygen reduction reaction in polymer electrolyte membrane fuel cells

Morphology of carbon nanofibers significantly effects Pt nanoparticles dispersion and specific interaction with the support, which is an important aspect in the fuel cell performance of the electrocatalysts. This study emphasizes, the defects creation and structural evolution comprised due to N–F co-doping on graphitic carbon nanofibers (GNFs) of different morphologies, viz. GNF-linearly aligned platelets (L), antlers (A), herringbone (H), and their specific interaction with Pt nanoparticle in enhancing the oxygen reduction reaction (ORR). GNFs–NF–Pt catalysts exhibit better ORR electrocatalytic activity, superior durability that is solely ascribed to the morphological evolution and the doped N–F heteroatoms, prompting the charge density variations in the resultant carbon fiber matrices. Amongst, H–NF–Pt catalyst performed outstanding ORR activity with exceptional electrochemical stability, which shows only 20 mV loss in the half-wave potential whilst 100 mV loss for Pt/C catalyst on 20,000 potential cycling. The PEMFC comprising H–NF–Pt as cathode catalyst with minimum loading of 0.10 mg cm^?2, delivers power density of 0.942 W cm^?2 at current density of 2.50 A cm^?2 without backpressures in H₂–O₂ feeds. The H–NF–Pt catalyst owing to its hierarchical architectures, performs well in PEMFC at the minimized catalyst loading with outstanding stability that can significantly decrease total price for the fuel cell.