钙钛矿型 Ba0.97Ca0.03Sn0.08Ti0.92O3-δ作为多硫化物固定剂在锂硫电池中的应用

制备具有氧空位的钙钛矿结构的Ba_0.97Ca_0.03Sn_0.08Ti_0.92O_3-δ(BCST)材料并将其作为多硫化物的固定剂,通过强的化学键合作用抑制多硫化物(LiPS)穿梭。作为促进LiPS转化的催化剂,BCST/KB/S(KB为科琴黑)正极在0.1C下提供了1 164.3 mAh·g^-1的初始放电容量,以及优异的循环稳定性。经过800次的充放电循环后,平均每次循环的容量衰减率仅为0.052%。     

SrTi0.9M0.1O3-δ钙钛矿型氧化物催化剂甲烷氧化偶联反应性能的研究

The structure and catalytic properties of SrTi_0.9M_0.1O_3-δ (M=Mg，Al， Zr) perovskite-type catalysts for ox-idative coupling of methane (OCM) have been studied by using X-ray diffraction (XRD)，X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption of oxygen(O₂-TPD) methods. It has been shown that doping the cations of lower valence (e.g. Mg²⁺， Al³⁺) to the B site of SrTi_0.9M_0.1O_3-δ perovskite-type catalysts results in the higher content of adsorbed oxygen species on the surface of catalysts and thus higher C₂-selectivity for OCM reaction. It is suggested that the oxygen vacancies of SrTi_0.9M_0.1O_3-δ (M=Mg， Al， Zr) perovskite-type catalysts are the sites responsible for oxygen activation， and the adsorbed oxygen species on the surface of SrTi_0.9M_0.1O_3-δ catalysts are the main active species for OCM reaction.     

SrTi1-xMgxO3-δ钙钛矿型氧化物催化剂甲烷氧化偶联反应性能的研究

The structure and catalytic properties of SrTi_1-xMg_xO_3-δ perovskite-type catalysts for oxidative coupling of methane (OCM) have been studied by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Temperature-programmed desorption (O₂-TPD) methods. It has been shown that doping Mg²⁺ cations to the B site of SrTi_1-xMg_xO_3-δ perovskite-type catalysts results in the formation of oxygen vacancies in the lattices of oxide cata-lysts. With increasing the amount of Mg²⁺ doped in the B site of SrTi_1-xMg_xO_3-δ, methane conversion and C₂ selectivity first increase and then decrease remarkably. The SrTi_1-xMg_xO_3-δ catalyst with x=0.1 has the highest methane conversion and C₂ yield. It is suggested that the oxygen vacancies produced by Mg²⁺ cations doping are the sites responsible for oxygen activation, and the adsorbed oxygen species on the surface of SrTi_1-xMg_xO_3-δ catalysts are the main active species for OCM reaction. However, the over high content of the adsorbed oxygen species on the surface results in the complete oxidation of methane. Introducing water steam into feedstock can improve the catalytic properties of SrTi_1-xMg_xO_3-δ perovskite-type catalysts for OCM reaction at lower temperature. The SrTi_0.9Mg_0.1O_3-δ catalyst has the methane conversion of 28.0 % with C₂ hydrocarbons selectivity of 36.8 % under reaction temperature of 550 ℃.     

类钙钛矿新铌酸盐Ba3La2Ti2Nb2O15的合成、结构与介电特性

为满足现代通信技术的小型化、集成化与高可靠性的迫切要求,探索具有高介电常数、低介电损耗与低温度系数的微波介电材料引起了材料科学、化学、物理和电子学等领域科学工作者的广泛关注,并已开发出复合钙钛矿结构[Ba(Zn1/3Ta2/3)O3]和钨青铜结构[Ba6-3xLn8+2xTi18O54]等实用化的高性.     

Y掺杂Ba0.90Sr0.08Ca0.02TiO3固溶体纳米晶粒尺寸 对其晶体结构的影响

The title nanocrystalline powders were prepared by sol-gel method, the influences of grain size on crystal structure were investigated by XRD and DSC techniques.The experiment results show that the tetragonal ferroelectric phase content of the powders and the Curie temperature Tc are increased with the increase of grain size.When the grain size is less than 34.7nm, crystal structure of the particle changes into cubic paraelectric phase and the transition of ferro-paraelectric phase disappears as well.     

SrFe0.6Cu0.3Ti0.1O3-δ混合导体透氧材料的稳定性

利用柠檬酸络合法制备了SrFe(Cu,Ti)O_3-δ混合导体透氧材料。 采用XRD、O₂-TPD、H₂-TPR、SEM等测试技术考察了材料的稳定性。 结果表明,SrFe_0.7Cu_0.3O_3-δ在低氧压下会发生相分解,产生SrCuO₂杂相,而掺杂Ti后的SrFe_0.6Cu_0.3Ti_0.1O_3-δ在低氧压下保持单一的钙钛矿结构。 H₂-TPR和O₂-TPD的测试表明,Ti⁴⁺的掺杂提高了材料的氧脱附起始温度和其它金属离子的还原温度。 SrFe_0.6Cu_0.3Ti_0.1O_3-δ膜在透氧过程中,会有Cu²⁺和Sr²⁺从钙钛矿结构中析出,在原晶粒边界形成新的小晶粒,但这种轻微的组分偏析没有影响到材料的透氧量,此透氧膜在66 h的操作过程中显示了良好的稳定性。     

Mg掺杂In2O3-x催化剂光热催化CO2加氢

为提高光热催化CO₂加氢In₂O₃催化剂的催化活性,采用均相水热法制备Mg (OH)₂-In (OH)₃前驱体,通过高温煅烧和H₂-还原处理得到了富含氧空位的Mg掺杂In₂O_3-x(Mg-In₂O_3-x)催化剂。在300℃、常压、可见光照射条件下,CO₂加氢转化为CO的CO₂转化率可达31.20%,CO产生速率为14.22 mmol·g_cat^-1·h^-1,CO选择性为100%。相比于单一In₂O_3-x催化剂,Mg-In₂O_3-x催化剂光热催化CO₂转化率及CO产生速率明显提高,这归因于Mg成功掺杂到In₂O₃晶格中,促进In₂O₃表面氧空位的形成,进而对可见光响应效率大幅提高,并有效减缓光生电子-空穴的复合。     

Mg掺杂In2O3-x催化剂光热催化CO2加氢

为提高光热催化CO₂加氢催化剂In₂O₃的催化活性,采用均相水热法制备Mg(OH)₂-In(OH)₃前驱体,通过高温煅烧和H₂-还原处理得到了富含氧空位的Mg掺杂In₂O_3-x(Mg-In₂O_3-x)催化剂。在300℃、常压、可见光照射条件下,CO₂加氢转化为CO的CO₂转化率可达31.20%,CO产生速率为14.22 mmol·gcat^-1·h^-1,CO选择性为100%。相比于单一In₂O_3-x催化剂,Mg-In₂O_3-x催化剂光热催化CO₂转化率及CO产生速率明显提高,这归因于Mg成功掺杂到In₂O₃形晶格中,促进In₂O₃表面氧空位的形成,进而对可见光响应效率大幅提高,并有效减缓光生电子-空穴的复合。     

类钙钛矿新铌酸盐Ba4LaTiNb3O15的合成、结构与介电特性

A new niobate compound Ba₄LaTiNb₃O₁₅ has been synthesized and characterized. Through Rietveld refinement of X-ray powder diffraction data, Ba₄LaTiNb₃O₁₅ is identified as the A₅B₄O₁₅ type cation-deficient perovskites with space group of P3m1(164) and lattice constants a=0.572 38(1) nm, c=1.169 48(1) nm, V=0.331 81(1) nm³, and Z=1. The crystal structure can be described as consisting of identical perovskite-like blocks, four corner-sharing (Ba,La)O₆ octahedra thick, separated by layers of vacant octahedral. The (Ba,La)-O bond lengths range from 0.267 to 0.321 nm and the (Ti,Nb)-O bond lengths range from 0.175 to 0.213 nm. The Ba₄LaTiNb₃O₁₅ ceramic has a high dielectric constant of 53.3, high quality factors (Q) 3 650 (at 6.402 5 GHz), and low temperature variation of resonant frequency (τ_f) +69.3 × 10^-6 K^-1.     

LaNi1-xFexO3钙钛矿型氧化物的制备与光催化降解性能

通过溶胶-凝胶法制备系列LaNi_1-xFe_xO₃（x=0.05, 0.1, 0.2, 0.4, 0.6和0.8）钙钛矿型氧化物光催化材料,采用X射线衍射进行结构表征,以甲基橙的降解率作为催化剂活性的评价指标,探究了实验条件对光催化活性的影响。结果表明,少量掺杂Fe³⁺可提高LaNiO₃的光催化活性,在所有样品中LaNi_0.95Fe_0.05O₃的光催化活性最高;当催化剂用量为1.0 g﹒L^-1时,对浓度为10 mg﹒L^-1的甲基橙溶液的光催化效果最佳,可见光照射120 min的降解率高达98.9%,5次重复使用后的降解率仍可达84.6%,具有稳定高效的重复利用性。      

高分散Co3O4对钙钛矿类LaCoO3低浓度甲烷催化燃烧性能的影响

本研究采用溶胶凝胶法,通过调变镧钴比合成了一种纳米新型钙钛矿类催化剂。利用物理吸附、ICP、XRD、H₂-TPR、O₂-TPD和XPS等技术对催化剂进行了表征,并对其在乏风甲烷氧化燃烧中的催化性能进行了研究。结果表明,高分散性的Co₃O₄纳米颗粒有利于甲烷的低温活化,且催化剂中镧钴钙钛矿体相可提供大量的晶格氧,促进高温下甲烷的催化燃烧速率和催化剂的高温稳定性。通过调变镧钴比例,可有效调变催化剂中Co₃O₄纳米颗粒的分散状态,进而实现催化剂低温活性和高温稳定性的有效统一。当La/Co比为0.9时,在空速为30000 mL/(gcat·h)的条件下,La0.9CoO₃钙钛矿催化剂的甲烷起燃温度为382℃;稳定运行72 h后,甲烷转化率保持在95%以上。这些结果为今后开发低成本、高活性和高稳定性的甲烷燃烧催化剂提供了参考。     

固体氧化物燃料电池La0.7Sr0.3Cr1-xMnxO3-δ阳极性能研究

采用溶胶凝胶法制备了La0.7Sr0.3Cr1-xMnxO3-δ(x=0.3,0.4,0.5,0.6)系列阳极粉体。在1000℃下焙烧后,XRD结果显示粉体物相为单一的钙钛矿相。制备以La0.7Sr0.3Cr1-xMnxO3-δ为阳极,Ce0.8Sm0.2O1.9(SDC)为电解质,Pr0.6Sr0.4Co0.8Fe0.2O3-δ-SDC复合阴极的电解质支撑型固体氧化物燃料单电池。由扫描电子显微镜(SEM)观察表明单电池电解质致密,阳极孔径分布均匀,厚度约为20μm,多孔阴极厚度为10μm。采用直流四电极法测试以La0.7Sr0.3Cr0.5Mn0.5O3-δ为阳极用湿氢气作燃料时在800℃下获得最大输出功率为232.84 mW.cm-2,短路电流为0.92 A.cm-2。     

g-C3N4/双钙钛矿复合材料的制备及氧催化性能

通过溶胶-凝胶法制备出不同Ni掺杂比例的双钙钛矿Sr_2Ni_xCo_(2-x)O_6(x=0.2,0.4,0.6,0.8),通过热分解法制备出具有层状结构的纳米颗粒g-C_3N_4,并制备其复合物催化剂。将双钙钛矿和g-C_3N_4分别制备成双功能电极片,用于测试其对氧还原(ORR)和氧析出(OER)的催化活性,然后选取具有最佳氧催化活性的Ni掺杂比例x=0.4的双钙钛矿与一定重量比例的g-C_3N_4进行复合,测试复合催化剂的氧催化活性。结果表明,复合后的催化剂催化效果明显优于单一催化剂,当g-C_3N_4添加量占双钙钛矿的30%(w/w)时复合催化剂催化氧还原反应的最大电流密度为395.7 mA·cm~(-2)(-0.6 V vs Hg/HgO),氧析出反应的最大电流密度为372.0mA·cm~(-2)(1 V vs Hg/HgO),这表明g-C_3N_4与Sr_2Ni_(0.4)Co_(1.6)O_6复合后协同催化能够提高双钙钛矿的氧催化活性。     

Conductivity and chemical stability of SrCe0.92Nb0.03Tm0.05O3-δ membrane prepared by modified sol-gel method

SrCe0.92 Nb 0.03 Tm0.05 O 3-δ powders were synthesized by a modified sol-gel method using citrate as a chelating agent.X-ray diffraction(XRD) analysis verified SrCe 0.92 Nb 0.03 Tm 0.05 O 3-δ powders and membranes consisting of a single perovskite phase.The morphologies of the sintered membranes were investigated by using scanning electron microscopy(SEM) technique.Stability tests demonstrated that the Nb introduction into doped strontium cerate greatly enhanced the chemical stability.Electrical conductivities of SrCe 0.92 Nb 0.03 Tm 0.05 O 3-δ and SrCe 0.95 Tm 0.05 O 3-δ were measured by the four-point DC method under 10% H 2 /He atmosphere and temperatures(700-900℃).With a maximum conductivity of 0.0067 S cm-1 at 900℃,the total electrical conductivity of SrCe 0.92 Nb 0.03 Tm 0.05 O 3-δ increases with increasing temperature.The H 2 permeation flux of SrCe 0.92 Nb 0.03 Tm 0.05 O 3-δ is 0.035 mL cm-2 min-1 when 40% H 2 /He and Ar were used respectively as the feed and sweeping gases at 900℃.     

复合阳极共烧制备致密La0.7Ca0.3Cr0.97O3-δ连接体薄膜的研究

固体氧化物燃料电池(SOFC)陶瓷连接材料的低成本薄膜化制备是现在公认的技术难题。为了改善传统NiO/YSZ阳极与LaCrO3基连接材料的共烧匹配性能,将化学性质稳定的Y0.7Ca0.3Cr0.9Zn0.1O3-δ(YCCZ)连接材料创造性地引入到NiO/YSZ阳极中,制备NiO/YSZ/YCCZ(6∶4∶2,m/m/m)三相复合阳极,并进行烧结特性、微观结构、电导率、热膨胀系数等系列性能的对比测试,结果表明NiO/YSZ/YCCZ新型复合阳极具有优良的综合性能。以NiO/YSZ/YCCZ为支撑体,采用浆料浸渍法制备湿膜,1 400℃空气条件下共烧,成功制备致密La0.7Ca0.3Cr0.97O3-δ连接体薄膜。     

核壳结构的Co3O4@δ-MnO2/Pt作为锂氧电池高效催化正极

通过简易、可控的水热方法在泡沫镍基体上直接生长了核壳结构的阵列型Co₃O₄@δ-MnO₂/Pt正极。阵列电极有利于电极的润湿、氧气的传输和Li₂O₂的负载。Co₃O₄@δ-MnO₂/Pt正极对氧还原和氧析出反应具有高的催化性能,可促使Li₂O₂依附Co₃O₄@δ-MnO₂/Pt阵列生长,从而保持阵列结构。该生长行为有利于Li₂O₂在充电时分解。以Co₃O₄@δ-MnO₂/Pt为催化正极的锂氧电池显示出高的容量（在电流密度100 mA·g^-1时容量为2 480 mAh·g^-1）,以及长的循环寿命（容量限定在500 mAh·g^-1时,在200 mA·g^-1电流密度下,可循环65次）,该性能超过了使用Co₃O₄或Co₃O₄@δ-MnO₂催化剂的电池。     

PO43-掺杂Bi2O2CO3/Bi0的制备及其可见光催化性能

构建氧空位以及附着金属单质Bi(Bi⁰)是增强半导体材料光吸收性能、促进半导体光生载流子分离的有效方法。通过简单的共沉淀法及氢气热还原成功制备了PO₄^3-掺杂Bi₂O₂CO₃附着Bi⁰(Bi-P-BOC)的可见光催化剂,并对其在可见光下催化降解氧氟沙星(OFX)的性能及机理进行了研究。材料表征结果表明BOC随着PO₄^3-的均匀掺杂,可见光吸收能力增强,表面缺陷增多,比表面积增大。而随着氢气热还原,BOC表面形成Bi⁰的同时也原位构建了大量的氧空位。可见光催化性能测试表明,Bi-P-BOC可以在180 min内降解约85%的OFX,降解速率为0.013 0 min^-1,是BOC降解速率的8倍。Bi-P-BOC光催化降解机理表明其具有更好的可见光吸收能力,Bi⁰以及氧空位的存在促进了光生载流子的分离,h⁺是其...     

Ce/Co比对Ag/CeO2-Co3O4催化剂低温氧化降解甲醛性能的影响

采用共沉淀法制备了一系列具有不同Ce/Co比的Ag/CeO₂-Co₃O₄催化剂,对其在甲醛低温氧化降解中的催化性能进行了研究。结果发现,Ag/CeO₂-Co₃O₄催化剂具有较好的甲醛低温降解活性,而Ce/Co比是影响其催化性能的一个重要因素。XRD、氮吸附-脱附、Raman光谱、H₂-TPR和in-situ DRIFTS等表征结果表明,随着Co含量的增加,Ag/CeO₂-Co₃O₄催化剂的孔体积随之增大,而比表面积减小。CeO₂有利于Ag/CeO₂-Co₃O₄催化剂的氧化还原性能提高,促进氧空位增加,提升Co²⁺的含量,从而有利于氧分子的活化,促进甲醛降解。同时,in-situ DRIFTS结果表明,甲酸盐物种的分解是甲醛在Ag/CeO₂-Co₃O₄催化剂表面催化氧化降解的速控步骤。     

Bi2Ti2O7/TiO2/Bi4Ti3O12多异质结的构筑及其增强的可见光催化性能

以静电纺丝技术制备的TiO₂纳米纤维为基质,硝酸铋为铋源,KOH为矿化剂,成功制备了多异质结Bi₂Ti₂O₇/TiO₂/Bi₄Ti₃O₁₂复合纳米纤维光催化剂。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外可见漫反射光谱(UV-Vis DRS)等一系列表征,对其物相组成、微观形貌和光学性质等进行分析。结果表明：TiO₂纳米纤维的介入,将Ⅰ型异质结Bi₂Ti₂O₇/Bi₄Ti₃O₁₂分离为2个Ⅱ型异质结Bi₂Ti₂O₇/TiO₂和Bi₄Ti₃O₁₂/TiO₂。Bi₂     

基于La0.6Ca0.4Fe0.7Sc0.1Ni0.2O3-δ氧电极的可逆固体氧化物电池性能研究

本研究制备了10%Sc掺杂的La_0.6Ca_0.4Fe_0.7Sc_0.1Ni_0.2O_3-δ(LCFSN)材料,采用半电池研究了该材料的氧还原催化活性(ORR)和氧析出催化活性(OER),发现LCFSN的ORR催化活性优于OER催化活性。组装了Ni-YSZ((Y₂O₃)_0.08(ZrO₂)_0.92)/YSZ/GDC(Gd_0.1Ce_0.9O_2-δ)/LCFSN全电池并研究了其在燃料电池模式(SOFC)和电解池模式(SOEC)下的电化学性能,电池在800℃以H₂为燃料时的最高功率密度可达1.471 W/cm²,在750℃, 50%H₂O和1.3 V热中性电解电压条件下其产氢速率高达627 mL/(cm²·h...