超声辐照制备SrFeO3降解苯酚光催化性能研究

采用超声辐照柠檬酸络合法制备了复合氧化物SrFeO3，以苯酚为光催化探针分子，以450W高压汞灯为光源（主波长〉410nm），研究了SrFeO3光催化性能、研究表明，经过超声辐照制备的SrFeO3光催化活性提高一倍以上。XRD、TEM、DRS表征结果表明，超声辐照制备的SrFeO3粒径均匀、分散性好、粒径较小，光吸收红移显著。探讨了超声提高催化性能的机理。     

Cobalt-free perovskite SrTa0.1Mo0.1Fe0.8O3-δ as cathode for intermediate-temperature solid oxide fuel cells

Ta⁵⁺ and Mo⁶⁺ substituted SrFeO_3-δ perovskites were researched as cathodes of intermediate-temperature solid oxide fuel cells (IT-SOFCs). The samples were synthesized with three components, e.g. mono-doped SrTa_0.2Fe_0.8O_3-δ, SrMo_0.2Fe_0.8O_3-δ and co-doped SrTa_0.1Mo_0.1Fe_0.8O_3-δ. Their phase structure, thermal stability, electrical conductivity and electrochemical catalytic property were researched comparatively. Ta⁵⁺ and Mo⁶⁺ co-doped SrTa_0.1Mo_0.1Fe_0.8O_3-δ possesses better electrochemical catalytic activity than that of the mono-doped SrFeO_3-δ. The performance difference between the mono-doped and co-doped SrFeO_3-δ has a close relation with the different contents of oxygen vacancy in the materials. The synergistic effect derived from Ta⁵⁺ and Mo⁶⁺ co-doping enhances the amount of oxygen vacancies in material, thus resulting in its better electrochemical property. The cells with SrTa_0.1Mo_0.1Fe_0.8O_3-δ as cathode deliver a R_p of 0.085 Ω·cm² and an output of 931 mW·cm^-2 at 800 °C.     

钙钛矿型CaxSr1-xFeO3的光催化活性研究

首先利用柠檬酸溶胶-凝胶法制备了钙钛矿型化合物SrFeO3纳米晶及其掺杂产物粉末,然后利用差热分析找出前驱体干凝胶的灰化温度和焙烧温度分别为400、700℃,利用XRD、TEM等检测手段对催化剂晶体进行了表征。结果表明,柠檬酸溶胶-凝胶法制备的SrFeO3复合氧化物的粒径50～70 nm,属于纳米级;利用紫外-可见光分光光度计测定了SrFeO3对亚甲基蓝溶液的催化性能,发现Ca的掺杂能够明显提高催化剂的催化性能,并得到Ca掺杂5%时（摩尔分数）的催化性能最佳。     

A Room‐Temperature Ferroelectric Ferromagnet in a 1D Tetrahedral Chain Network

Ferroelectricity occurs in crystals with broken spatial inversion symmetry. In conventional perovskite oxides, concerted ionic displacements within a 3D network of transition‐metal–oxygen polyhedra (MO_x) manifest spontaneous polarization. Meanwhile, some 2D networks of MO_x foster geometric ferroelectricity with magnetism, owing to the distortion of the polyhedra. Because of the fundamentally different mechanism of ferroelectricity in a 2D network, one can further challenge an uncharted mechanism of ferroelectricity in a 1D channel of MO_x and estimate its feasibility. Here, ferroelectricity and coupled ferromagnetism in a 1D FeO₄ tetrahedral chain network of a brownmillerite SrFeO_2.5 epitaxial thin film are presented. The result provides a new paradigm for designing low‐dimensional MO_x networks, which is expected to benefit the realization of macroscopic ferro‐ordering materials including ferroelectric ferromagnets.     

微波加热法制备SrFeO3光催化材料的研究

提出了一种新的制备SrFeO3光催化材料的方法,微波加热法。实验确定其最佳制备条件为：微波功率560W,微波加热时间30min,煅烧温度700℃和煅烧时间5h;对在该条件下制备的催化剂进行了XRD表征。在可见光条件下,以模拟染料酸性大红废水为目标物,对催化材料的光催化性能进行了研究,结果表明微波加热法制备的光催化材料具有较高的光催化降解性能,染料降解率最高可达93．4％。     

SrBiFeO基NTC陶瓷的制备及其电性能研究

以Bi2O3、Fe2O3和SrCO3为主要原料,采用传统固相法制备出具有NTC特性的SrBiFeO(SBF)陶瓷。研究了该陶瓷的物相结构、断面形貌及电性能。结果表明:试样由BiFeO3、SrFeO3-x和三方晶系的Sr2.25Bi6.75O12.38相组成,试样的室温电阻率ρ25随Fe2O3掺杂量的增加呈现先减小后增大的趋势,而B25/85值却呈现单调递增趋势,陶瓷试样SBF30即:n(Bi2O3):n(SrCO3):n(Fe2O3)=50:70:15时具有较好的NTC特性,ρ25为1.192×103Ω.cm,B25/85值为3 604 K。     

共沉淀法合成铁酸锶及其光催化活性研究

用共沉淀法制备了纳米粉SrFeO3-x, 并以XRD、IR、UV-Vis等手段对其进行了表征,以活性艳红水溶性染料的降解脱色率为标志测定了其光催化活性.同时研究了制备纯物相的条件及物相纯度、溶液pH值对光催化活性的影响.结果表明：在1 000 ℃制得单一SrFeO3-x立方钙钛矿相;单一相在中性溶液里无显著的光催化活性,而含有杂相的SrFeO 3-x具有很高的光催化活性;不论是否纯相,光催化剂在酸性溶液里活性很高,在碱性溶液里活性极低.     

SrFeO_3阳极催化剂对乙醇电催化氧化性能研究

用溶胶凝胶法制备了钙钛矿型氧化物SrFeO3,热重分析(DTA-TG)和X射线衍射(XRD)分别对制备过程和产物进行分析和表征.用循环伏安、计时电流、交流阻抗(EIS)方法测试了所得产物对常温下碱性介质中乙醇电化学氧化的催化性能.循环伏安曲线、计时电流和交流阻抗结果表明,在乙醇溶液中,阳极电流密度大于氢氧化钾溶液中的阳极电流密度,并且随着电极中乙醇浓度的增加,电流密度也增加,在乙醇溶液中,SrFeO3电极的电荷迁移阻抗明显降低,表明SrFeO3对乙醇电化学氧化有催化作用.可以此为基础,研究开发应用于直接乙醇燃料电池阳极的非贵金属催化材料.     

钙钛矿型LaFeO3和SrFeO3的光催化性能

采用柠檬酸法合成钙钛矿型复合氧化物LaFeO3和SrFeO3,并以其为光催化剂对不同水溶性染料进行光催化降解实验.结果表明:SrFeO3的光催化活性明显高于LaFeO3,这与A位离子(La3+,Sr2+)的电子构型的不同有关.