新型二维碳材料——石墨烯在光催化分解水制氢中的研究进展

能源危机和日益严重的环境污染问题是目前人类生存和发展面临的严峻挑战,在化石能源日益枯竭的今天,清洁太阳能的转化、储存和利用成为当前研究的热点.利用太阳能光催化分解水制氢,并将太阳能以氢能的形式储存是解决能源问题最理想     

中空纳米材料的构建原理及其在光催化制氢和二氧化碳还原反应中的应用

随着全球经济的快速发展,能源短缺与环境污染成为当今世界共同关注的热点问题,开发和利用洁净能源成为当务之急.近年,以半导体为基础的光催化技术引起了国内外的广泛关注,其中包括光催化分解水制氢、光催化还原CO2、光催化固氮以及光催化降解污染物等.尤其太阳能驱动的光催化分解水和光催化CO2还原均可将太阳能转化为可储存和运输的化...     

太阳能光催化制氢研究进展

随着人类社会的快速发展和传统能源的急剧消耗,能源紧缺和环境污染已经成为制约人类社会可持续发展的重要因素,构建清洁的环境友好的可再生新能源体系是当前各国高度关注的焦点和重大战略.在众多绿色环保、可持续新能源选项中,半导体光催化制氢因其可利用清洁可再生的太阳能制取高效清洁氢能,有望完全解决能源紧缺和环境污染问题,成为最有应用前景的技术之一. 本文通过概述半导体光催化制氢原理、半导体光电化学及光电稳定性、半导体光催化制氢效率,重点介绍半导体光催化剂、光生电荷分离及光催化制氢体系等方面若干新进展,并对太阳能光催化制氢技术的发展加以评述和展望.     

基于二氧化钛光催化剂生物质转化制备氢气和化学品的研究进展

随着化石能源的枯竭和环境问题的日益严重,发展可再生资源变得越来越重要.太阳能和生物质是自然界中的两大可再生资源.利用太阳能转化生物质制备H2和化学品可以缓解对化石能源的依赖,是解决能源和环境问题的途径之一.本文作者概述了基于TiO2催化剂的光催化生物质制备H2和化学品的研究进展;着重介绍了甲醇、乙醇、甘油和葡萄糖的光催化反应选择性问题和机理研究,分析了存在的问题和可能的解决措施,并就其发展趋势进行了展望.     

构建S型异质结COF/CdS以增强太阳光产氢

高效利用太阳能是解决当前能源危机和环境问题的有效途径.光催化制氢技术具有绿色环保、成本低等优势,且氢气可作为能源载体,其燃烧产物仅为水,因此被认为是实现高效利用太阳能的最佳途径之一.为更好地利用太阳能,研究者们致力于开发具有良好可见光活性的光催化剂.CdS因具有良好的电荷转移能力和在可见光区域强吸收的特性,在光催化制氢...     

太阳能光催化分解水制氢※

利用太阳能光催化分解水制氢是解决能源环境问题并实现太阳能有效转化和储存最有前途的技术之一, 这一“圣杯”式反应经过几十年不懈努力取得了诸多重要研究进展. 本文将综述光催化分解水制氢体系的基本概念、活性测试方法与注意事项、光催化材料种类等; 并从光催化分解水制氢的光吸收、光生电荷分离和表面催化反应等基本过程和关键科学问题的角度总结其重要研究进展, 最后对于太阳能光催化分解水制氢的挑战和潜在的发展方向进行分析和展望. 希望通过本综述的简要介绍能让刚从事光催化分解水制氢研究的青年科技人员清晰地了解掌握该领域的一些基本概念、操作规范、研究总体进展和现状等.     

光催化：电子的奇妙之旅

半导体光催化技术可以利用太阳能光催化分解水制备氢气和降解有机污染物以解决能源问题和环境污染问题,并且具有反应低能耗、低温深度反应和反应具有光谱性等优点,是解决环境和能源问题领域中最具有应用前景的新技术之一。本文通过将半导体光生电子拟人化,以电子先生的旅游视角介绍了光催化反应中电荷的转移过程,介绍了光催化技术在制氢和降解有机污染物领域中的应用。     

功能化Cu2O光催化研究进展

光催化技术是利用太阳能解决能源短缺和环境污染等问题的有效方法之一.因此,开发一种具有高效光催化活性的光催化材料具有重要意义.Cu₂O是一种窄带隙的P型半导体材料,因其成本低、制备方法简单以及高可见光活性被广泛应用于光催化、传感和储能材料等领域.本文主要结合氧化亚铜光催化机理概述了功能化氧化亚铜光催化性能研究进展,介绍了杂原子掺杂、贵金属负载、半导体复合、碳材料复合以及三元复合材料等改性方法,最后对氧化亚铜基光催化材料的应用前景做出了展望.     

钛基钙钛矿型光催化材料的研究进展

由于化石能源的快速消耗以及化石能源在燃烧过程中会释放有害气体,所以寻找新的、干净的能源体系迫在眉睫。氢能具有高燃烧值和高效率的优点,成为了目前最有前景的新能源之一,而利用太阳能进行光催化产氢是最符合"绿色化学"的方法之一。根据目前所探究的光催化剂,钙钛矿型光催化剂因其多样性、特征性以及可变性成为了热门的研究体系。钛基钙钛矿材料及其衍生物表现出了许多优异的光催化活性,是太阳能光催化研究领域的研究热点。本文详细综述了钛基钙钛矿材料及其衍生物的结构、改性方式以及在光催化分解水领域的研究进展。     

铋基光催化剂的金属或非金属改性研究进展（英文）

随着经济的快速增长,环境和能源问题日益突出。太阳能作为一种可再生、环保的能源,受到了许多研究人员的关注,最大限度地利用太阳能资源成为未来的研究热点。众所周知,光催化技术可以将太阳能转化为化学能或电能,为环境污染提供解决方案。因此,半导体光催化技术被认为是解决能源危机和环境问题的最环保的技术之一。铋基半导体材料由于合适的能带结构、丰富的种类、无毒性和低成本,在光催化领域受到欢迎。然而,纯Bi基光催化剂存在光激发电子-空穴对复合效率高、量子产率低和光吸收能力有限的问题,导致光催化性能低。为了克服这些限制,人们设计了各种策略,比如金属或非金属掺杂、金属沉积、异质结构建和诱导缺陷生成来提高它们的光催化活性。在这些策略中,元素掺杂或金属沉积被认为是调整铋基材料能带结构和物化性质的有效方法。这个方法拓宽了光响应范围和提高了光催化性能。这篇综述总结了金属掺杂、非金属掺杂、金属和非金属共掺杂以及金属沉积改性铋基材料的最新研究进展。它也探索了它们在光催化降解污染物和重金属离子、氮气还原、二氧化碳还原、光催化抗菌等各个领域的应用。关于金属掺杂,我们将其分为三类：碱金属或碱土金属掺杂、过渡金属掺杂和稀土金属...     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.