Fe掺杂A-TiO_2在溴甲酚绿中的可见光催化活性及动力学

以FeCl_3·6H_2O为Fe源,采用水热法制备了Fe掺杂锐钛型TiO_2(A-Ti O2)光催化剂。以溴甲酚绿为降解对象,考察溴甲酚绿的初始浓度、催化剂用量、掺Fe量等因素对自制催化剂可见光催化降解反应的动力学方程的影响。结果表明:在40 W白炽灯照射下,当溴甲酚绿初始浓度为10 mg/L(pH=7)、催化剂的用量为0.6 g/L、掺Fe量为4%(摩尔分数)、室温下反应时间为3 h时,溴甲酚绿的降解率最大为76.05%。溴甲酚绿光催化降解曲线符合一级反应动力学方程,于上述最佳条件下其表观反应速率常数k达到最大值,为0.389 7 h-1。     

Fe掺杂改性TiO_2光催化膜的性能

二氧化钛是一种具有半导体性质的光催化剂,可利用低能量的紫外光照射,进行有机污染物光催化的分解反应。用溶胶凝胶法合成Ti O2,并在其中掺杂Fe3+。在玻璃片上制备了Ti O2薄膜,并用此薄膜对甲基橙在紫外光和可见光下进行降解。发现经过掺杂的薄膜在450℃处理后,不会对Ti O2结构产生明显的影响,但可大大提高Ti O2在紫外光照射下对污染物的分解效率,并且大大拓展了Ti O2对可见光的响应范围。     

组合外加电场提高Fe∶LiNbO_3中90°记录体全息的衍射效率

针对90°全息记录结构的特殊性,在记录和读出阶段分别施加不同极性的外加电场,实现了Fe∶LiNbO3晶体中高衍射效率的全息记录和读出。在库赫塔列夫(Kukhtarev)方程基础上引入两维耦合波理论,对组合外加电场提高掺铁铌酸锂晶体光折变特性的机理进行了探讨。实验和理论计算结果都表明这种分别在记录和读出过程施加不同极性组合的外加电场是在Fe∶LiNbO3中实现高衍射效率90°记录结构体全息的有效技术方案。     

Influences of Fe Element on the Structural and Electrochemical Performances of LiNi0.5Co0.2Mn0.3O2 Cathode Materials

The effect of Fe element on the structural and electrochemical performance of the Layered LiNi_0.5Co_0.2Mn_0.3O₂ materials with various Fe-doped amounts synthesized by high-temperature solid state method had been studied quantitatively and in detail. The structural and morphological of the prepared samples were characterized by X-ray diffraction patterns (XRD) and scanning electron microscopy (SEM). The study results show that the discharge capacity and cycling performance of the LiNi_0.5Co_0.2Mn_0.3O₂ all reduced by Fe doping, that is mainly attributed to the aggravated disorder degree of the layered structure and charge transfer resistance. Fe content should be controlled strictly in the layered LiNi_1?x?yCo_xMn_yO₂ cathode materials production process.     

Single atom iron carbons supported Pd–Ni–P nanoalloy as a multifunctional electrocatalyst for alcohol oxidation

Exploring high-performance and multifunctional electrocatalysts for alcohols oxidation is the key to develop alkaline fuel cells. Herein, we prepared a novel palladium-nickel-phosphorus catalyst supported on single atom iron carbons (SAICs) with different diameter sizes (1000 nm, 200 nm, 100 nm, 50 nm, and 20 nm), which were synthesized by direct carbonization of Fe-doped Zeolitic Imidazolate Framework-8 (ZIF-8). Electrochemical tests reveal that the as-prepared PdNiP/50nmSAIC exhibited excellent electrooxidation activity and stability to the various alcohols (methanol, glycerol, and especially ethylene glycol) electrooxidation in the alkaline solution, which is much higher than that of commercial Pd/C and other advanced Pd-based catalysts. Meanwhile, the rotating disk electrode (RDE) and CO-stripping results proves that PdNiP/50nmSAIC possesses a faster kinetic process of ethylene glycol oxidation and enhanced anti-CO poisoning ability. Our efforts provide a new strategy for the development of MOFs-derived multielement electrocatalyst with excellent activity and stability, and a bright future for alcohol oxidation.     

SrTi1−x Fe x O3 nanoparticle: a study of structural,optical, impedance and magnetic properties

We investigate the effects of Fe-dopant concentration on the structure, as well as optical, electrical transport and magnetic properties of SrTi_{1? x} Fe _x O₃ (x?=?0.00, 0.10, 0.20, 0.30, 0.40 and 0.50) nanoparticles prepared by sol–gel method. The dopant-induced changes are studied by X-ray diffraction (XRD), Raman, optical absorption, impedance and magnetic measurements. The results show an average particle size of about 15–30?nm, depending on the Fe-doped concentration. The decrease in lattice parameters and the change of phonon modes related to structural changes, decreasing gap with increasing dopant concentration in conjunction with increasing grain boundary contribution to the impedance. The Fe-doped content has affected the structure, absorption and Raman spectroscopy of the samples. These indicate that the Fe ion has replaced the site of Ti in unit cell. By this method, we have decreased the annealing temperature considerably than that in the conventional solid-state reaction.     

Dielectric properties of Fe-doped Ba0.65Sr0.35TiO3 thin films fabricated by the sol–gel method

Fe-doped Ba_0.65Sr_0.35TiO₃ (BST) thin films have been fabricated on Pt/Ti/SiO₂/Si substrate using the sol–gel method. The structural and surface morphology, dielectric, and leakage current properties of undoped and 1 mol% and 2 mol% Fe-doped BST thin films have been studied in detail. The results demonstrate that the Fe-doped BST films exhibit improved dielectric loss, tunability, and leakage current characteristics as compared to the undoped BST thin films. The improved figure of merit (FOM) of Fe-doped BST thin film suggests a strong potential for utilization in microwave tunable devices.     

Improving ultraviolet light photocatalytic activity of polyaniline/silicon carbide composites by Fe-doping

It was aimed to prepare polyaniline (Pani) composites, including silicon carbide (SiC) nanofibers doped with iron (Fe) ions. The Fe-doping of SiC was performed to enhance the photocatalytic activity of the composites through the separation of photoexcited mobile charge carriers. For comparison purposes, Pani composites were also prepared with undoped SiC nanofibers. The composite samples were characterized by FTIR, XRD, SEM, EDX, and UV–Vis spectroscopies. Experiments on photocatalytic degradation of methylene blue under ultraviolet light irradiation revealed that Pani/SiC-Fe composites exhibited higher photocatalytic activity when compared with Pani/SiC composites. Almost 22% dye removal was obtained within 300 min with the Pani composite, containing 15 wt.% SiC-Fe. FTIR, XRD, SEM, EDX, and UV–Vis spectroscopies demonstrated that SiC nanofibers were successfully doped with iron ions and incorporated into the polyaniline matrix. The original aspect of this study was to research the photocatalytic activity of polyaniline composites containing Fe-doped SiC nanofibers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48524.     

Structural investigations on TiO2 and Fe-doped TiO2 nanoparticles synthesized by laser pyrolysis

Undoped and Fe-doped TiO₂ nanopowders with Fe/Ti (atomic ratio) precursor concentration ranging from 7% up to 25% have been prepared by the IR laser pyrolysis technique. A sensitized mixture of TiCl₄ and Fe (CO)₅ was used as titanium and iron precursor, respectively. Reference undoped titania samples with a major concentration of anatase phase (about 90%) were obtained by the same technique by using very high flows of the oxidizing agent (air). The effects of the iron-dopant concentration on the essential structural properties of the resultant powders such as the phase formation, the crystallinity, the average particle size and distributions were systematically investigated by X-ray diffraction, Raman spectroscopy and transmission electron microscopy. The decrease of the TiO₂-anatase crystalline phase, the simultaneous increase of the amorphous phase and the decrease in size of particle mean diameter appear as main effects induced by the Fe-dopant concentration.     

树脂软模板修饰铁掺杂g-C3N4光催化剂的制备及性能

采用一步熔融法,将三聚氰胺甲醛树脂MF与铁元素一同掺杂到纳米g-C₃N₄上,成功获得树脂软模板修饰铁掺杂g-C₃N₄新型复合光催化剂g-C₃N₄/MF/Fe。采用X射线多晶衍射分析(XRD)、傅里叶变换红外光谱(FT-IR)、扫描电子显微镜(SEM)、紫外漫反射光谱(UV-vis)等多种手段对掺杂前后的复合光催化剂进行了表征。以罗丹明B为染料模型,研究了复合催化剂的染料降解性能。结果表明,将MF树脂与铁元素一同掺杂到g-C₃N₄上,复合光催化剂对罗丹明B有优异的降解能力,40 min可以实现染料完全降解,催化剂的禁带宽度由2.63 eV降低至1.43 eV。