二氧化钛纳米粒子催化合成Hantzsch酯和多氢喹啉衍生物(英文)

1,4-Dihydropyridine and polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using nanosized titanium dioxide as a heterogeneous catalyst.The present methodology offers several advantages such as excellent yields,short reaction times (30-120 min),environmentally benign,and mild reaction conditions.The catalyst can be readily separated from the reaction products and recovered in excellent purity for direct reuse.     

Preparation,Characterization and Photocatalytic Activity of Lanthanum Doped Mesoporous Titanium Dioxide

Lanthanum doped mesoporous titanium dioxide photocatalysts with different La content were synthesized by template method using tetrabutyltitanate (Ti(OC₄H₉)₄) as precursor and Pluronic P123 as template. The catalysts were characterized by thermogravimetric dif-ferential thermal analysis, N₂ adsorption-desorption measurements, X-ray diffraction, and UV-Vis adsorption spectroscopy. The effect of La³⁺ doping concentration from 0.1% to 1% on the photocatalytic activity of mesoporous TiO₂ was investigated. The characterizations indicated that the photocatalysts possessed a homogeneous pore diameter of about 10 nm with high surface area of 165 m²/g. X-ray photoelectron spectroscopy measurements in-dicated the presence of C in the doped samples in addition to La. Compared with pure mesoporous TiO₂, the La-doped samples extended the photoabsorption edge into the visible light region. The results of phenol photodecomposition showed that La-doped mesoporous TiO₂ exhibited higher photocatalytic activities than pure mesoporous TiO₂ under UV and visible light irradiation.     

铽负载介孔二氧化钛的制备、表征和协同效应

以嵌段共聚物P123为模板剂,采用蒸发诱导自组装法制备了铽负载介孔TiO2光催化剂,并利用XRD、N2吸附解吸和UV-Vis吸收光谱等技术手段对样品进行了表征。 制备的样品为锐钛矿和金红石混合晶相,以罗丹明B为模拟有机降解物,样品显示了良好的可见光催化活性。 研究发现0.7%的铽负载和380 ℃的煅烧温度是较佳的制备条件。 介孔结构所具有的高的比表面积、小的晶粒尺寸、铽负载诱导的电荷分离和可见光吸收增强协同提高了光催化活性。 同时,提出了铽负载二氧化钛诱导增强光催化作用的机理。     

Nipagin-Functionalized Porphyrazine and Phthalocyanine—Synthesis,Physicochemical Characterization and Toxicity Study after Deposition on Titanium Dioxide Nanoparticles P25

Aza-porphyrinoids exhibit distinct spectral properties in UV-Vis, and they are studied in applications such as photosensitizers in medicine and catalysts in technology. The use of appropriate peripheral substituents allows the modulation of their physicochemical properties. Phthalocyanine and sulfanyl porphyrazine octa-substituted with 4-(butoxycarbonyl)phenyloxy moieties were synthesized and characterized using UV-Vis and NMR spectroscopy, as well as mass spectrometry. A comparison of porphyrazine with phthalocyanine aza-porphyrinoids revealed that phthalocyanine macrocycle exhibits higher singlet oxygen generation quantum yields, reaching the value of 0.29 in DMF. After both macrocycles had been deposited on titanium dioxide nanoparticles P25, the cytotoxicities and photocytotoxicities of the prepared materials were studied using a Microtox^® acute toxicity test. The highest cytotoxicity occurred after irradiation with a red light for the material composed of phthalocyanine deposited on titania nanoparticles.     

铋掺杂介孔二氧化钛的制备及光催化动力学

以介孔分子筛(KIT-6)为载体,采用溶液浸渍法合成了铋(Bi)掺杂的介孔二氧化钛(TiO₂)光催化剂。利用XRD、TEM、SEM、XPS、N₂吸附-脱附法和拉曼光谱法等技术手段对材料的结构和形貌进行表征。通过紫外-可见吸收光谱法考察了催化剂对罗丹明B光催化降解效率,进一步考察了Bi的掺杂量对光催化反应速率的影响,并对光催化降解动力学进行了初步研究。结果表明,Bi掺杂的介孔TiO₂具有较窄的孔径分布(3~4 nm),而且吸收范围扩展到可见光区,其光催化活性明显高于商品TiO₂(P25)。随之Bi掺杂量的提高,反应速率常数也增大,其光催化降解罗丹明B的反应均符合准一级动力学方程。     

铽(III)掺杂TiO2纳米材料相转移和光催化性质研究

以无水丁二醇为溶剂在中性条件下用溶胶凝胶法制备了系列Tb~(3+)(x=0. 0025～0.07)均匀掺杂的二氧化钛纳米材料。研究结果表明，Tb~(3+)掺杂对纳米二 氧化钛的相转移有很强的抑制作用。这种抑制作用的强弱与Tb~(3+)掺杂的浓度有 密切关系，Tb~(3+)(x = 0.02)的掺杂对TiO_2锐钛矿(anatase)向金红石(rutile) 转化的抑制作用最强。伴随着发生相转移温度的提高，掺杂纳米二氧化钛材料的高 温烧结大大缓解，掺杂纳米TiO_2的热稳定性明显增强；掺杂浓度越高，热稳定性 提高越大。对罗丹明的光降解实验表明，Tb~(3+)掺杂可以有效提高TiO_2光催化活 性。对不同浓度、不同煅烧温度样品光催化降解活性进行系统考察后发现，Tb~ (3+)(x=0.02)掺杂的样品在不同煅烧温度下均显示出最好的光催化效率，说明掺杂 浓度对其光催化性质影响很大。用浸渍法制备的样品其光催化活性较纯的二氧化钛 低，并且其催化活性随浸渍浓度的增加而降低，表明稀土离子的分布是影响稀土掺 杂纳米TiO_2光催化性质的主要因素之一。     

Preparation,Characterization, and Electrocatalytic Properties of Cobalt Oxide and Cobalt Hexacyanoferrate Hybrid Films

Polynuclear mixed‐valent films of cobalt oxide and cobalt hexacyanoferrate (CoOCoHCF) have been deposited on electrode surfaces from a solution of Co²⁺ and Fe(CN)₆^3? ions by repetitive potential cycling method. Simultaneous cyclic voltammetry and electrochemical quartz crystal microbalance measurements demonstrate the steady growth of modified film. The effect of type of monovalent cations as well as acidity of the supporting electrolyte on film growth and redox behavior of resulting film was investigated. In pure supporting electrolyte, electrochemical responses of modified electrode resemble with that of a surface immobilized redox couple. The hybrid film electrodes showed electrocatalytic activity toward oxidation of NADH, hydrazine and hydroxylamine. The feasibility of using our modified electrodes for analytical application was also explored.     

镧掺杂二氧化钛纳米管光催化性能

以多孔有序阳极氧化铝为模板,利用溶胶-凝胶法制备掺杂La的二氧化钛纳米管,用场发射扫描电子显微镜、X射线衍射仪和比表面分析仪对其进行表征,以甲基橙为目标降解物,对比未掺杂的二氧化钛纳米粉、纳米管以及掺杂的二氧化钛纳米粉研究其光催化性能,并对降解机制进行分析。结果表明：适量的掺杂有利于提高二氧化钛纳米管的光催化性能,掺杂存在一个最佳量,本试验条件下为1%（质量分数）。掺杂的二氧化钛纳米管光催化性能优于掺杂的纳米粉。     

An Overview of Metal-Organic Framework Based Electrocatalysts: Design and Synthesis for Electrochemical Hydrogen Evolution,Oxygen Evolution,and Carbon Dioxide Reduction Reactions

Due to the increasing global energy demands, scarce fossil fuel supplies, and environmental issues, the pursued goals of energy technologies are being sustainable, more efficient, accessible, and produce near zero greenhouse gas emissions. Electrochemical water splitting is considered as a highly viable and eco-friendly energy technology. Further, electrochemical carbon dioxide (CO₂) reduction reaction (CO₂RR) is a cleaner strategy for CO₂ utilization and conversion to stable energy (fuels). One of the critical issues in these cleaner technologies is the development of efficient and economical electrocatalyst. Among various materials, metal-organic frameworks (MOFs) are becoming increasingly popular because of their structural tunability, such as pre- and post- synthetic modifications, flexibility in ligand design and its functional groups, and incorporation of different metal nodes, that allows for the design of suitable MOFs with desired quality required for each process. In this review, the design of MOF was discussed for specific process together with different synthetic methods and their effects on the MOF properties. The MOFs as electrocatalysts were highlighted with their performances from the aspects of hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and electrochemical CO₂RR. Finally, the challenges and opportunities in this field are discussed.     

Synthesis and Characterization of Mesoporous Titanium Dioxide Spheres

Mesoporous titanium dioxide spheres were synthesized by a convenient solvothermal method at room temperature with tetraethyl titanate as a precursor. Investigation by means of X-ray diffraction(XRD), transmission electron microscopy(TEM), scanning electron microscopy(SEM), and N2 adsorption-desorption isotherms confirms that the sample has a mesostructure with a higher specific surface area and shows that the mesoporous TiO2 spheres have a diameter of 2 μm, the average pore size is about 5.9 nm, and the BET...     

C-N-S-TiO2光催化剂的制备、表征及其性能

以钛酸四丁酯为钛源、功能生物小分子胱氨酸为掺杂剂,采用溶胶-凝胶法同步合成了C-N-S-TiO2光催化剂,利用XRD、XPS、FT-IR和DRS等测试技术对样品的结构及物化性能进行了表征。XRD和DRS分析表明,共掺杂抑制了TiO2晶粒的生长,提高了晶相转变温度,且C-N-S-TiO2样品的吸收带边明显"红移",光吸收范围一直延长至800 nm左右。XPS分析结果显示,C-N-S-TiO2样品表面产生了杂质能级,C、S元素分别取代部分晶格Ti4+以CO23-和S6+形式存在;而N峰呈宽化状态,以O—Ti—N和Ti—O—N键存在,且样品表面羟基含量明显增加。以罗丹明B染料为模型污染物,考察了该催化剂的可见光催化活性。结果表明,与P25 TiO2比较,C-N-S-TiO2光催化剂活性得到改进,C-N-S-TiO2光催化剂在470～800 nm波长下辐射120 min后对罗丹明B的降解率可高达83%。     

纳米氧化钛与小鼠乙酰胆碱酯酶的作用关系

纳米TiO₂已在各领域得到广泛应用, 由于其小尺寸效应、表面效应、量子尺寸效应等性质因而具有很强的生物学效应, 易进入人体内, 因而担心对人的健康构成潜在危害作用, 但其作用机制不明朗. 通过体内和体外实验相结合的研究方法, 运用光谱学的手段, 研究了纳米TiO₂颗粒与乙酰胆碱酯酶(AChE)结构-功能的作用关系. 结果表明, 在体内, 随着纳米TiO₂颗粒处理剂量的增加, AChE活性明显增加. 在体外, 一定浓度范围内纳米TiO₂颗粒对AChE有显著的激活作用. 光谱学分析证实纳米TiO₂颗粒与AChE直接发生结合作用, 强结合位点数为1.6个, 结合常数为2.56×10⁷ L•mol^－1, 而弱结合位点的结合常数为3.06×10⁶ L•mol^－1. 过多纳米TiO₂颗粒的结合将导致AChE去折叠并破坏其二级结构. 提示纳米TiO₂颗粒处理引起小鼠体内AChE活性的变化可能与纳米TiO₂颗粒结合后引起AChE的结构变化有密切关系.     

A novel ball-in-ball hollow oxygen-incorporating cobalt sulfide spheres as high-efficient electrocatalyst for oxygen evolution reaction

Transition-metal chalcogenides with hollow nanostructure,especially cobalt sulfides,are considered as the most pro mising non-precious metal catalysts for oxygen evolution reactio n.However,it is difficult to synthesize oxygen-containing cobalt sulphides with hollow structure due to the different physical/chemical properties between metal sulfides and metal cobalts.Herein,we report a novel oxygencontaining amorphous cobalt sulfide ball-in-ball hollow sphere s(Co-S-O BBHS) synthesized by an anion exchange method.Taking advantage of the ball-in-ball hollow structure,the amorphous Co-S-O BBHS shows supe rior oxygen evolution reaction(OER) electrocatalytic performance with a low overpotentiat of285 mV at 10 mA/cm~2,small Tafel slope of 49.67 mV/dec,high Faraday efficiency of 96%,and satisfied durability.Experiments and DFT calculations demonstrate that the introduction of oxygen and sulfur modulates the electronic structure of Co-S-O BBHS,thus enhancing the adsorption of *0(adsorbed 0 species on catalyst surface) intermediate,which greatly boosts the catalytic activity towards OER.This work provides a new strategy for controllable synthe sis of complex hollow structures of transition-metal chalcogenides for OER.     

共沉淀法制备氧化硅改性的纳米二氧化钛及其性质

采用共沉淀法合成了氧化硅改性的具有高比表面积的纳米二氧化钛.氧化硅的添加提高了二氧化钛纳米颗粒的热稳定性能,有效地抑制了纳米二氧化钛的颗粒增长、团聚和锐钛向金红石的晶型转换.光催化降解亚甲基蓝证明,样品具有较高的光催化活性,而且随着氧化硅添加量的增加,光催化活性提高.     

氮掺杂石墨烯的制备及氧还原电催化性能

采用两步热解法, 用尿素掺杂氧化石墨烯(GO)得到N掺杂的还原氧化石墨烯(N-RGO), 通过控制反应温度, 制备了具有不同电催化活性的N掺杂的还原氧化石墨烯. 透射电子显微镜(TEM)和扫描电子显微镜(SEM)结果显示, 制得的氮掺杂石墨烯(nG)表面褶皱和重叠增加. X射线光电子能谱(XPS)证明, 氮元素以吡啶N、 吡咯N和石墨化的N 3种形式掺杂在石墨烯中, 最高摩尔分数为6.6%. 通过循环伏安(CV)和旋转圆盘电极(RDE)测试了nG的电化学性能, 结果表明, 在酸性电解质中对氧还原(ORR)有较高的催化活性, 起始电位在0.1 V左右, 电催化还原氧气时主要为四电子反应, 且相对商用的Pt/C催化剂有更好的电化学稳定性, 其中第一步热解温度为200℃制得的nG催化性能最好.     

核-壳和中空多面体二氧化钛制备、表征及光催化

本文采用水热法控制制备了具有特殊纳米结构的核-壳和中空多面体二氧化钛, 以进一步提高具有特定暴露面多面体二氧化钛的比表面积, 达到更优异的光催化效果。用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)等技术对所制备特殊结构二氧化钛的物相和微/纳结构进行表征分析, 结果表明所得核-壳和中空结构多面体二氧化钛具有一个类似隧道结构的(001)/(001)洞开的截顶双金字塔型壳层。这两种特殊结构的形成可能是源于配位/弱酸性腐蚀原理的共同作用。用核-壳和中空结构二氧化钛对亚甲基蓝进行光降解实验, 结果表明:所得两种新颖结构二氧化钛的光催化效率得到明显提高, 尤其是在添加过氧化氢条件下。可能原因是:两种特殊结构二氧化钛大比表面积正面作用抵消了(001)晶面消失或减少所产生的副作用, 以及过氧化氢在光催化反应中提供的活性氢氧根自由基使得光辐照二氧化钛产生的电子-空穴对在催化剂表面得到有效分离。     

核-壳和中空多面体二氧化钛制备、表征及光催化

本文采用水热法控制制备了具有特殊纳米结构的核-壳和中空多面体二氧化钛,以进一步提高具有特定暴露面多面体二氧化钛的比表面积,达到更优异的光催化效果。用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)等技术对所制备特殊结构二氧化钛的物相和微/纳结构进行表征分析,结果表明所得核-壳和中空结构多面体二氧化钛具有一个类似隧道结构的(001)/(001)洞开的截顶双金字塔型壳层。这两种特殊结构的形成可能是源于配位/弱酸性腐蚀原理的共同作用。用核-壳和中空结构二氧化钛对亚甲基蓝进行光降解实验,结果表明:两种新颖结构二氧化钛具有优异的光催化性能,尤其是在添加过氧化氢条件下。可能原因是:两种特殊结构二氧化钛大比表面积正面作用抵消了(001)晶面消失或减少所产生的副作用,以及过氧化氢在光催化反应中提供的活性氢氧根自由基使得光辐照二氧化钛产生的电子-空穴对在催化剂表面得到有效分离。     

Synthesis of Cobalt Sulfide/Sulfur Doped Carbon Nanocomposites with Efficient Catalytic Activity in the Oxygen Evolution Reaction

Cobalt sulfide/sulfur doped carbon composites (Co₉S₈/S‐C) were synthesized by calcining a rationally designed sulfur‐containing cobalt coordination complex in an inert atmosphere. From the detailed transmission electron microscopy (TEM) and X‐ray photoelectron spectroscopy (XPS) analyses, the electrocatalytically active Co₉S₈ nanoparticles were clearly obtained and combined with the thin sulfur doped carbon layers. Electrochemical data showed that Co₉S₈/S‐C had a good activity and long‐term stability in catalyzing oxygen evolution reaction in alkaline electrolyte, even better than the traditional RuO₂ electrocatalyst. The excellent electrocatalytic activity of Co₉S₈/S‐C was mainly attributed to the synergistic effect between the Co₉S₈ catalyst which contributed to the oxygen evolution reaction and the sulfur doped carbon layer which facilitated the adsorption of reactants, prevented the Co₉S₈ particles from aggregating and served as the electrically conductive binder between each component.     

Regulating the Spin State of FeIII by Atomically Anchoring on Ultrathin Titanium Dioxide for Efficient Oxygen Evolution Electrocatalysis

Ferric oxides and (oxy)hydroxides, although plentiful and low‐cost, are rarely considered for oxygen evolution reaction (OER) owing to the too high spin state (e_g filling ca. 2.0) suppressing the bonding strength with reaction intermediates. Now, a facile adsorption–oxidation strategy is used to anchor Fe^III atomically on an ultrathin TiO₂ nanobelt to synergistically lower the spin state (e_g filling ca. 1.08) to enhance the adsorption with oxygen‐containing intermediates and improve the electro‐conductibility for lower ohmic loss. The electronic structure of the catalyst is predicted by DFT calculation and perfectly confirmed by experimental results. The catalyst exhibits superior performance for OER with overpotential 270 mV @10 mA cm^?2 and 376 mV @100 mA cm^?2 in alkaline solution, which is much better than IrO₂/C and RuO₂/C and is the best iron‐based OER catalyst free of active metals such as Ni, Co, or precious metals.