Double Hydrothermal Synthesis of Graphene Supported TiO_2(b)Nanosheets as Anode Materials for Lithium Ion Batteries

The synthesis of graphene supported TiO2（b） nanosheets by a double hydrother- mal method for lithium storage was reported. The titanate nanosheets synthesized by the first hydrothermal progress and the graphene oxide obtained by the oxidation of graphite were hydrothermally treated together to fabricate the TiO2（b）/graphene composite. The electrochemical measurements illustrate that the graphene supporter obviously improves the cyclic performance of TiO2（b）, which can be attributed to the better dispersion and the decrease of resistance for the TiO2（b） nanosheets in the composite.

Pt/FeSnO(OH)_5： A Novel Supported Pt Catalyst for Catalytic Oxidation of Benzene

Pt/FeSnO（OH）_5 was synthesized as a novel catalyst for VOCs oxidation. Compared with Pt/γ-Al_2O_3 during catalytic oxidation of benzene, Pt/Fe Sn O（OH）5 showed better catalytic activity. After characterization of the catalysts by XRD, SEM, TEM, EDS, XPS, BET, TGA and DTA, we found most Pt could be reduced to metallic state when the hydroxyl catalyst was used as supporter, and the metallic Pt in Pt/Fe Sn O（OH）5 was more active than the oxidized Pt in Pt/γ-Al_2O_3 in catalytic oxidation of VOCs. Pt/FeSnO（OH）_5 shows both good catalytic activity and high stability, which may be a promising catalyst. This study may also be helpful for the design and fabrication of new catalysts.

Electrochemical Catalytic Properties of Pt/FeSnO(OH)_5 towards Methanol Oxidation

The Pt/FeSnO（OH）_5 catalyst has been prepared by depositing Pt nanoparticles on the synthesized FeSnO（OH）_5 nanoboxes and demonstrates excellent performance towards methanol oxidation reaction（MOR） in direct methanol fuel cells（DMFCs）.The Pt/FeSnO（OH）_5 catalyst exhibits a higher mass activity（1182.35 mA/mgPt） compared with Pt/C（594.57 mA/mgPt） catalysts.The X-ray powder diffraction,field emission scanning electron microscope,field emission transmission electron microscopy,X-ray photoelectron spectroscopy and electrochemical experiments have been employed to explore the relationships between the crystal structure and electrochemical properties.The increased activity and resistance of CO poisoning for Pt/FeSnO（OH）_5 catalyst can be attributed to the strong interaction between the transition metal in the hydroxide and Pt and the bifunctional effect.The higher relative concentration of Pt^0 in Pt/FeSnO（OH）_5 also contributes to the MOR activity.Moreover,the charge transfer resistance of Pt/FeSnO（OH）_5 is lower than that of Pt/C.Therefore,Pt/FeSnO（OH）_5 has great application prospect as a high-performance electrocatalyst in DMFCs.

Photoluminescent Property Effect of Sc_(3+) on Er_(3+)/Y_(3+)/Yb_(3+) Doped Al_2O_3 Powders

The photoluminescence （PL） property effect of Sc3＋ on the Er3＋/Y3＋/Yb3＋ doped Al2O3 powders prepared by sol-gel method has been investigated. The X-ray diffraction （XRD） and transmission electron microscopy （TEM） implied that the distribution of dopants （Er3＋ , Y3＋ , Yb3＋ , Sc3＋） was improved effectively with the rise of Sc3＋ concentration. The Fourier transform infrared spectra （FTIR） results demonstrated that the ligand around the quenching center -OH and the population of -OH were altered by introducing different amounts of Sc3＋ . The PL intensity centered at 1530 nm was increasingly improved with the rise of Sc3＋ concentration, as well as the corresponding full widths at the half maximum （FWHM） and lifetime. The optimized PL intensity was 4.7 times higher than that non-Sc3＋ doped sample for the Al2O3 powders codoped with 10mol% Sc3＋ . This material can be promising candidates for optical fiber amplifier.

Facile Synthesis, Morphologies and Gas Sensing Properties of CuO Powder

CuO powder with microspheres,submicron sheets had been synthesized only from CuSO4 and Na2CO3 aqueous solutions by a facile route.Significant effects of initial droplet size of CuSO4 aqueous solution were observed on particle size,morphology and gas sensitivity of CuO.The morphologies of CuO powder varied from microspheres to submicron sheets with the introduction method of CuSO4 to Na2CO3 aqueous solutions.Based on the characterized structure and morphology,a possible formation mechanism of CuO had been proposed.High gas sensitivity to ethanol was obtained for the CuO microspheres synthesized by spray method,which exhibited the response sensitivity of 3.25 to ethanol with the concentration of 300 ppm at 250℃.It suggests that the facile route is promising to the batch synthesis of CuO powder with good gas sensing properties.

Upconversion Luminescence Properties of NaY0.92Yb0.05Er0.03F4 Enhanced by Zr^4＋ Codoping

In this paper we present a novel report on the upconversion luminescence performance of NaY0.92Yb0.05Er0.03F4 enhanced by Zr^4＋ codoping. The luminescence intensity of the tridoped hexagonal NaYF_4 synthesized by a hydrothermal method increased to the maximum, about seven times of the non-Zr^4＋ sample when the Zr^4＋ codoping concentration rose to 6 mol%, while the luminescence lifetime was also prolonged by Zr^4＋ codoping. To explore the relationships between the microstructure and upconversion properties, X-ray powder diffraction, field emission scanning electron microscope, electron energy-dispersive spectroscopy and upconversion emission spectroscopy were employed. From these characterizations, we found that the codoping of Zr^4＋ could modulate the crystal microstructure of NaYF_4 for higher upconversion luminescence intensity and longer lifetime. This study may be helpful for the design and synthesis of high-performance upconversion materials.

In^(3+)共掺杂诱导NaY_(0.95-x)Yb_(0.03)Er_(0.02)F_4相转变与上转换发光增强研究

引入In3+作为新的掺杂离子通过水热法合成了In3+与Er3+,Yb3+共掺杂的NaYF4上转换发光材料.通过XRD表征及Rietveld精修,SEM以及TEM研究了In掺杂引起的NaYF4形貌与晶体结构的变化.通过发射光谱与发光衰减曲线表征了掺杂NaYF4的上转换发光性能,以研究晶体微观结构与上转换发光性能之间的关系.结果表明随着In掺杂量的增加,立方相NaYF4的晶格畸变不断增强且发生由立方相向六方相的转变.对于六方相NaYF4,其上转换发光强度随着In含量的提高不断增强并当In含量为3%时达到最大值.该研究结果可以有助于设计与合成具有优良上转换发光性能的材料.

不同形貌Er,Yb共掺六方NaYF_4的合成及上转换发光特性研究

利用水热法成功合成了不同形貌的稀土掺杂六方NaY0.95Yb0.03Er0.02F4,包括柱状、粒状、片状、管状等.通过XRD,SEM,TEM对合成样品的物相结构及晶粒形态进行了表征,探讨络合剂EDTA用量;表面活性剂CTAB,P123,十二烷基苯磺酸钠;热溶剂水、乙二醇、聚乙二醇对晶体生长方向的影响,并对不同形态样品进行上转换发光性能测试,分析晶粒形态对上转换发光强度与寿命的影响,结果显示晶粒越小发光强度越强,相当粒径的管状样品的发光强度比粒状的强,不同晶粒形态上转换的主要能量传递模式也不相同.研究结果可以指导我们可控合成适应实际应用需求的晶粒形态及优良上转换发光性能的材料.

Hf^(4+)共掺NaYF_4:Yb/Tm提高上转换发光性能研究

利用X射线多晶衍射仪、场发射扫描电镜、场发射透射电镜、X射线光电子能谱和荧光光谱仪对相近半径离子Hf^(4+)和Zr^(4+)共掺六方Na YF_4:Yb^(3+)/Tm^(3+)的结构、形貌和上转换发光性能进行研究.结果表明Hf^(4+)和Zr^(4+)离子共掺六方Na YF_4:Yb^(3+)/Tm^(3+)可有效调控晶场的不对称性,Hf^(4+)相对于Zr^(4+)是个更好的掺杂离子,它在调控晶场的同时还参与Tm^(3+)离子上转换发光的能量传递过程,明显提高了短波500 nm以下发射带的荧光强度;而Zr4+离子仅扮演晶场调控角色而未能参与稀土离子Tm^(3+)的上转换发光过程,Tm^(3+)离子小于500 nm短波发射带的荧光强度没有得到明显的提高,仅提高802 nm发射带的荧光强度.该研究发现Hf^(4+)可作为蓄能离子参与稀土离子的上转换发光过程,有助于将Hf^(4+)作为蓄能离子和晶格操纵工具用于设计和制备其它高性能的稀土上转换发光材料.

硅藻土辅助制备有序介孔碳及其电催化性能

以共聚物F127为软模板,酚醛树脂为碳源,引入硅藻土充当暂态支架,在不同硅藻土与酚醛树脂质量比下,用蒸发自组装法合成有序介孔碳材料.利用XRD,TEM,N2吸附-脱附对其结构进行表征,结果显示,与单一软模板相比,在硅藻土辅助下获得的介孔碳材料不仅具有高度有序的孔道,还具有更大的比表面积(717～773 m2 g-1)和孔径(3.9～11.3 nm).依据原料比例与介孔碳结构两者间的变化规律,初步探讨了硅藻土在制备中所起的辅助作用.采用微波多元醇还原法制备介孔碳载Pt电催化剂,在甲醇溶液中进行循环伏安测试,发现比表面积的增大有利于碳材料的电催化性能提高,当硅藻土与酚醛树脂的比例为0.5时,制备出的有序介孔碳比表面积最大,载Pt后呈现的正向氧化峰电流也最大.

Eu^(3+)/Tb^(3+)/MoO_4^(2–)掺杂钨酸钙体系荧光粉的结构及其发光性能

采用化学共沉淀法合成了Ca0.75Mg0.2Tb0.02Eu0.03(WO4)1-x(Mo O4)x(x=0~1.0)系列荧光粉,并对荧光粉的晶体结构和发光性能进行了表征。结果表明:不同Mo O42–掺杂量的样品均为四方相Ca0.75Mg0.2Tb0.02Eu0.03(WO4)1-x(Mo O4)x固溶体。在273 nm波长紫外光激发下,随着x的增大,Eu3+离子的发光强度先增强后减弱,当x=0.6时发光强度最强,为未掺杂Mo O42–样品的6倍。Mo O42–共掺杂改变了稀土离子周围的配位环境和局部晶体场的对称性,促进Eu3+离子4f电子的超敏跃迁,提高Eu3+的O2–→Eu3+电荷迁移跃迁,增加基体、Tb3+离子与Eu3+离子之间的能量传递。

羟基锡酸盐载铂复合催化剂Pt/(Co,Zn)Sn(OH)_6的合成及其甲醇电催化氧化性能

以羟基锡酸盐CoSn(OH)6和ZnSn(OH)6纳米空心立方体为前体,采用抗坏血酸作为弱还原剂,经过超声过程分别合成了羟基锡酸钴载Pt/CoSn(OH)6和羟基锡酸锌载Pt/ZnSn(OH)6复合催化剂,并在甲醇氧化反应(MOR)中表现出良好的性能。Pt/CoSn(OH)6和Pt/ZnSn(OH)6催化剂的单位质量活性分别为1 095.6mA/mg和699.5mA/mg,高于C载Pt(Pt/C)的594.6mA/mg。利用XRD、SEM、TEM、XPS和电化学测试对催化剂晶体结构和性能间的关系进行了探索。CO溶出实验结果表明,羟基锡酸盐载体有利于Pt表面CO的去除,载体与Pt间的强相互作用和载体表面的大量羟基基团增强了催化剂的催化活性和CO抗毒性。此外,Pt/(Co,Zn)Sn(OH)6催化剂中单质Pt高的相对含量也有利于提高MOR活性。通过研究载铂羟基锡酸盐电催化氧化甲醇性能,能够揭示载体结构对催化性能的影响,有助于羟基锡酸盐载铂复合催化剂在直接甲醇燃料电池(DMFCs)领域的应用。

不同质量浓度5-氟尿嘧啶联合曲安奈德治疗瘢痕疙瘩的多中心前瞻性随机对照临床研究

目的评价不同质量浓度的5-氟尿嘧啶联合曲安奈德治疗瘢痕疙瘩的临床效果。方法2018年3月—2019年3月,将福建医科大学附属协和医院整形外科接诊的29例患者31个瘢痕疙瘩、平潭综合实验区医院皮肤科接诊的11例患者20个瘢痕疙瘩、福州市仓山迪娅医疗美容门诊部接诊的9例患者9个瘢痕疙瘩纳入此前瞻性随机对照研究,其中男27例、女22例,年龄(30±9)岁。将瘢痕疙瘩按随机数字表法分为低质量浓度组(19个瘢痕疙瘩,17例患者)、中质量浓度组(21个瘢痕疙瘩,19例患者)、高质量浓度组(20个瘢痕疙瘩,17例患者),分别采用质量浓度为0.5、5.0、12.5 mg/mL的5-氟尿嘧啶联合曲安奈德注射治疗,每4周注射1次,共3次。首次治疗前及末次治疗后3个月,采用温哥华瘢痕量表(VSS)评价瘢痕疙瘩外观、采用视觉模拟评分法(VAS)评定瘢痕疙瘩疼痛和瘙痒程度,并计算治疗前后的评分差值。末次治疗后6个月,采用疗效满意度评价量表行患者疗效满意度评分。记录治疗期间不良反应。末次治疗后1年随访,统计瘢痕疙瘩复发率。对数据行χ^(2)检验、单因素方差分析、配对样本t检验、LSD-t检验、Wilcoxon秩和检验、Kruskal-Wallis秩和检验、Fisher确切概率法检验。结果首次治疗前,3组瘢痕疙瘩外观VSS评分相近(F=0.039,P>0.05);末次治疗后3个月,低质量浓度组瘢痕疙瘩外观VSS评分明显高于中质量浓度组及高质量浓度组(t=2.267、4.086,P<0.05或P<0.01)。末次治疗后3个月,低质量浓度组、中质量浓度组、高质量浓度组瘢痕疙瘩外观VSS评分均较首次治疗前明显降低(t=18.222、44.272、22.523,P<0.01)。低质量浓度组瘢痕疙瘩治疗前后外观VSS评分差值明显低于中质量浓度组与高质量浓度组(t=-4.096、-6.357,P<0.01),中质量浓度组瘢痕疙瘩治疗前后外观VSS评分差值明显低于高质量浓度组(t=-2.368,P<0.05)。首次治疗前,3组瘢痕疙瘩疼痛和瘙痒VAS评分相近(χ^(2)=0.149,P>0.05);末次治疗后3个月,低质量浓度组瘢痕疙瘩疼痛和瘙痒VAS评分明显高于中质量浓度组及高质量浓度组(Z=2.191、4.386,P<0.05或P<0.01),中质量浓度组瘢痕疙瘩疼痛和瘙痒VAS评分明显高于高质量浓度组(Z=2.276,P<0.05)。末次治疗后3个月,中质量浓度组和高质量浓度组瘢痕疙瘩疼痛和瘙痒VAS评分均较首次治疗前明显降低(Z=-3.904、-3.844,P<0.01)。低质量浓度组瘢痕疙瘩治疗前后疼痛和瘙痒VAS评分差值明显低于中质量浓度组与高质量浓度组(Z=-4.265、-6.104,P<0.01)。末次治疗后6个月,高质量浓度组瘢痕疙瘩对应患者疗效满意度评分为(88±8)分,明显高于中质量浓度组的(76±8)分和低质量浓度组的(60±8)分(t=-3.820、-6.675,P<0.01),中质量浓度组瘢痕疙瘩对应患者疗效满意度评分明显高于低质量浓度组(t=-2.984,P<0.05)。3组瘢痕疙瘩治疗期间仅疼痛差异明显(P<0.01)。末次治疗后1年随访,高质量浓度组瘢痕疙瘩复发率明显低于低质量浓度组(χ^(2)=8.313,P<0.01),中质量浓度组瘢痕疙瘩复发率与低质量浓度组、高质量浓度组相近(χ^(2)=3.536、0.577,P>0.05)。结论高质量浓度的5-氟尿嘧啶联合曲安奈德治疗瘢痕疙瘩后,症状改善明显,患者治疗满意度增加,无明显不良反应且疗效持久,较中、低质量浓度的5-氟尿嘧啶整体效果好,值得临床推广。