硫掺杂改性二氧化钛光催化剂的研究进展

二氧化钛具有良好的稳定性、低成本和无二次污染等特点，有着广阔的应用前景．但禁带较宽致使紫外光激发成为制约其应用的瓶颈，拓宽二氧化钛的光谱响应范围、实现可见光激发是二氧化钛光催化材料面临的主要问题。综述了非金属硫掺杂二氧化钛的制备方法及光催化机理的研究进展，并展望了今后值得关注与研究的问题。     

纳米二氧化钛光催化性能的研究进展及应用前景

纳米二氧化钛是一种新型半导体材料,因其具有优良的光催化特性,在太阳能储存与利用、光电转换、光致变色及光催化降解大气和水中污染物等诸多方面具有广阔的应用前景.对目前纳米二氧化钛光催化性能的研究情况以及光催化应用前景进行了综述.     

二氧化钛掺杂改性的研究进展

二氧化钛作为一种具有光催化活性的氧化物半导体材料,在利用太阳能降解环境污染物的领域具有广阔的应用前景。但是,由于二氧化钛存在光量子产率低,禁带宽度较大,光催化反应活性较低等缺点,严重阻碍了其在实际应用中的发展。目前,为改善二氧化钛的光催化性能,多种化学物质被用于二氧化钛的掺杂研究,包括过渡金属、贵金属、非金属和稀土元素等,不论是对二氧化钛进行单独掺杂或共掺杂都已被广泛地研究,结果表明,适当的掺杂将显著提高二氧化钛的光催化活性。本文对该领域的研究现状进行了综述,在此基础上对二氧化钛掺杂改性研究的发展进行了展望。     

纳米TiO_2的光催化性能改进及其在环境保护中的应用研究

基于纳米二氧化钛光催化性能的广泛应用及其在应用时效率偏低的问题,从抑制TiO2内载流子的复合、提高催化剂的比表面积和改变催化剂的结构与表面性质3个方面综述了修饰纳米二氧化钛以提高其光催化性能的各项措施,并从污水处理、空气净化、抗菌除臭等方面评述了纳米TiO2在环境保护领域中的应用。     

纳米二氧化钛固相载体研究进展

目前,随着工业化社会的快速发展,由有机物引发的环境污染问题日益严重,而常用的有机物处理技术无法满足实际的应用需求,因此,需要开发更加高效、先进的有机物处理技术.纳米二氧化钛有良好的光催化降解有机物的能力,在光照作用下,可将有机物完全降解为对环境无污染的CO2和H2 O,有着广阔的应用前景.在实际应用中,纳米二氧化钛存在比表面积大、易团聚的问题,会使其光催化活性降低.而且纳米粉体形式的二氧化钛存储、运输和使用困难,回收利用成本高,二氧化钛的损耗量大.但将二氧化钛负载于固相载体上,可以很好地解决这些问题,有利于促进纳米二氧化钛光催化剂商业化的推广和应用.本文综述了纳米二氧化钛固相载体的研究进展,系统介绍了负载纳米二氧化钛常用的固相载体和负载方法.     

二氧化钛基纳米材料及其在清洁能源技术中的研究进展

二氧化钛纳米材料是当前纳米科技的研究热点,其在太阳能光催化分解水制氢、二氧化碳的光催化还原、染料敏化太阳能电池等清洁能源技术方面均显示了重大的应用前景.本文主要综述了近年来二氧化钛基纳米材料的研究趋势、存在的主要问题,以及这些材料在上述清洁能源利用中的最新进展.对备受关注的非金属掺杂、高能面暴露的二氧化钛、染料敏化太阳能电池阳极致密层等热点问题进行了评述和展望.     

纳米二氧化钛光催化氧化技术

纳米TiO2光催化氧化技术是近年来备受关注的一项节能高效、绿色环保型新技术.详细评述了光催化氧化作用机理、提高纳米二氧化钛光催化活性的途径以及光催化氧化技术的应用.对当前该技术的研究现状以及存在的问题进行了分析,并提出了今后的发展方向.     

二氧化钛光催化研究进展及应用

综述了二氧化钛光催化研究的国内外进展及发展概况,并就其光催化机理、载体形式、应用等方面树了概述。     

TiCl_4自生晶种水解法制备纳米二氧化钛

采用TiCl4自生晶种水解法制备纳米二氧化钛,研究了反应物的添加方式和浓度对二氧化钛粉体形貌和晶相的影响,制备了粒径20～30nm,分散性好的球状纳米二氧化钛。用亚甲基蓝的光催化降解研究了最佳条件下所制备的二氧化钛粉体的光催化活性。结果表明:该二氧化钛粉体对亚甲基蓝的光催化降解在100min内可达95%以上,具有较高的光催化活性。     

二氧化钛纳米管阵列的应用研究进展

二氧化钛纳米管阵列具有独特的结构、良好的化学惰性、更大的比表面积、纳米管与基底结合牢固等优点,其应用非常广泛.综述了二氧化钛纳米管阵列在太阳能电池、传感器、光解水制氢、光催化和环境分析方面的应用研究进展,并提出了二氧化钛纳米管阵列的应用发展趋势及展望.     

Hybrid organic-inorganic light-emitting diodes

The demonstration of colour tunability and high efficiency has brought organic light-emitting diodes (OLEDs) into the displays and lighting market. However, high production costs due to expensive deposition techniques and the use of reactive materials still limit their market entry, highlighting the need for novel concepts. This has driven the research towards the integration of both organic and inorganic materials into devices that benefit from their respective peculiar properties. The most representative example of this tendency is the application of metal oxides in organic optoelectronics. Metal oxides combine properties such as high transparency, good electrical conductivities, tuneable morphology, and the possibility of deposition on large areas with low-cost techniques. The use of metal oxides as charge injection interfaces in OLEDs has also been investigated. Hybrid organic-inorganic light-emitting diodes (HyLEDs) are inverted OLEDs that employ air-stable metal oxides as the charge injection contacts. They are emerging as a potential competitor to standard OLEDs, thanks to their intrinsic air stable electrodes and solution processability, which could result in low-cost, large area, light-emitting devices. This article reviews the short history of this class of devices from its first solid state example published in 2006 to the present achievements. The data presented shed light on the electronic mechanism behind the functioning of HyLEDs and give guidelines for their further optimization.     

二氧化钛非金属氮掺杂的研究进展

二氧化钛具有稳定性好、光效率高和不产生二次污染等特点,有着广阔的应用前景.当前的研究热点为通过金属以及非金属的掺杂改性来提高其可见光活性及抑制电荷复合.介绍了二氧化钛非金属氮掺杂改性的研究进展.分别对氮掺杂机理、制备方法以及共掺杂等方面进行了详细的综述.     

Electro catalytic oxidation reactions for harvesting alternative energy over non noble metal oxides: Are we a step closer to sustainable energy solution?

Methanol oxidation reaction and oxygen evolution reaction are the two fundamental and bottleneck reactions of methanol and hydrogen economy. Due to cost, slow reaction kinetics and associated poisoning issues with noble metal catalysts, a substantial amount of research have been focused on non-noble metal structured oxides, where the solid state structure coupled with its unique surface properties have demonstrated low overpotentials and high current densities with fascinating chemistry and potential to commercialization. The transition metal oxides with cubic rock salt, spinel and perovskite structures have been the interest of research for many years for methanol oxidation reaction and oxygen evolution reaction. However, in spite of significant studies, there is not a single monograph on compiling and critically comparing the mechanism and performances of these two electrocatalytic oxidation reactions over structured oxides. This review probes the mechanism and efficiency of methanol oxidation reaction and oxygen evolution reaction in light of solid state structures, anionic vacancies, corresponding surface morphologies and electronic configurations of oxide catalysts. An overall critical conclusion is drawn at the end of this article.     

Defects-Driven Ferromagnetism in Undoped Dilute Magnetic Oxides:A Review

In the past several decades, dilute magnetic semiconductors, particularly the dilute magnetic oxides have evolved into an important branch of materials science due to their potential application in spintronic devices combining of properties of semiconductors and ferromagnets. In spite of a major effort devoted to the mechanism of ferromagnetism with a high Curie temperature in these materials, it still remains the most controversial research topic, especially given the unexpected d0 ferromagnetism in a series of undoped wide-band-gap oxides films or nanostructures. Recently, an abundance of research has shown the critical role of various defects in the origin and control of spontaneous magnetic ordering, but contradicting views from intertwined theoretical calculations and experiments require more in-depth systematic research. In our previous work, considerable efforts have been focused on two major oxides, i.e. ZnO and ZrO 2. This review will present a summary of current experimental status of this defect-driven ferromagnetism in dilute magnetic oxides(DMOs).     

Solid‐State Diffusional Behaviors of Functional Metal Oxides at Atomic Scale

Metal/metal oxides have attracted extensive research interest because of their combination of functional properties and compatibility with industry. Diffusion and thermal reliability have become essential issues that require detailed study to develop atomic‐scaled functional devices. In this work, the diffusional reaction behavior that transforms piezoelectric ZnO into magnetic Fe₃O₄ is investigated at the atomic scale. The growth kinetics of metal oxides are systematically studied through macro‐ and microanalyses. The growth rates are evaluated by morphology changes, which determine whether the growth behavior was a diffusion‐ or reaction‐controlled process. Furthermore, atom attachment on the kink step is observed at the atomic scale, which has important implications for the thermodynamics of functional metal oxides. Faster growth planes simultaneously decrease, which result in the predominance of low surface energy planes. These results directly reveal the atomic formation process of metal oxide via solid‐state diffusion. In addition, the nanofabricated method provides a novel approach to investigate metal oxide evolution and sheds light on diffusional reaction behavior. More importantly, the results and phenomena of this study provide considerable inspiration to enhance the material stability and reliability of metal/oxide‐based devices.     

Partially decomposed PVP as a surface modification of ZnO,CdO, ZnS and CdS nanostructures for enhanced stability and catalytic activity towards sulphamethoxazole degradation

In order to prepare stable and efficient photocatalysts, a microwave-furnace-assisted method using ethylene glycol (EG) as a solvent has been employed to obtain metal oxides and metal sulphides nanocatalysts with partial decomposition of the polyvinylpyrrolidone (PVP) cap (P-ZnO, P-CdO, P-ZnS and P-CdS); this associates the protective functionality of PVP with enhanced catalytic activity due to effective carriers transfer. The as-produced catalysts characterization revealed an extended growth of metal oxides compared with metal sulphides, which is attributed to the competition of EG as the source of oxygen with PVP to capsulate metal oxides during the synthesis. Infrared spectra confirmed the PVP–metal complexation and partial decomposition of the polymer. Metal sulphides exhibited a better catalytic activity compared with metal oxides for sulphamethoxazole degradation in UVC light owing to their size and morphology impact; further, P-CdS induced 71% antibiotic degradation after 10 h of illumination with visible light compared with only 48% for P-ZnS, 29% for P-ZdO and 20% for P-CdO due to improved light absorption. Interestingly, around 86% degradation was induced by mixing P-CdS with P-ZnS in 80:20% ratio, indicating an enhanced visible light activity due to improved electron–hole pair separation and high redox potential of P-ZnS.     

Metal oxide applications in organic-based photovoltaics

Abstract

Organic-based photovoltaics (PV) have attracted increasing attention in recent years and efficiencies exceeding 8% have recently been confirmed. These low cost, lightweight and mechanically flexible devices offer unique advantages and opportunities currently unavailable with crystalline silicon technology. Progress in the field of organic PV has been achieved in part due to the incorporation of transition metal oxides. These offer a wide range of optical and electronic properties, making them applicable in organic-based PV in many capacities. Transparent electrodes can be made from doped metal oxides. The high intrinsic charge carrier mobility of many undoped metal oxides makes them attractive as active materials and charge collectors. Metal oxides can increase the charge selectivity of the electrodes due to the energetic positioning of their valence and conduction bands. Thin films of these materials can manipulate the light distribution inside of organic devices, allowing for improved light harvesting. Metal oxides are stable and can be processed at low temperatures. Consequently, they have been demonstrated as suitable intermediate layer materials in tandem cells. Finally, oxygen-deficient metal oxides can improve the stability of the oxygen- sensitive organic semiconductors. The present work reviews the various applications of metal oxide layers in organic PV devices and summarises the challenges associated with organic/oxide interfaces.     

催化氧化法去除烟气中NOx的研究现状与展望

综述了SCO法(选择性催化氧化法)中催化剂的研究现状。从过渡金属元素、稀土元素、贵金属、活性炭四类催化剂进行了介绍。锰类复合氧化物催化剂具有较高的催化活性,且成本较低。钙钛矿催化剂的催化活性能与贵金属类催化剂相媲美。这些非贵金属催化剂成本都较低,具有潜在的应用价值。但总的来说目前对于催化剂抗硫抗水的研究还不够深入,一些催化剂可能还未达到实际工业应用中应具有的抗中毒能力。总结分析了SCO法应用中存在的问题,展望了其应用前景。     

Synthesis and characterization of IR up-conversion material CaS:Eu, Sm by low-temperature combustion synthesis method

Infrared up-conversion material CaS:Eu, Sm was synthesized by the low-temperature combustion synthesis (LCS) method, which has expanded the application range of the LCS method which is always used in the synthesis of oxides and compound oxides. The combustion process was discussed and the effect of the amount of carbamide on the up-conversion luminescence properties was analyzed. XRD patterns show that the products are with the cubic CaS crystal structure. Spectral analysis indicates that the sample can be excited effectively by ultraviolet or visible light to store energy, and subsequently is sensitive to 800-1600 nm infrared light and then emit red light resulting from the multi-transitions of Eu²⁺ 4f⁶5d → 4f⁷(⁸S_7/2).     

Noninvasively Modifying Band Structures of Wide‐Bandgap Metal Oxides to Boost Photocatalytic Activity

Although doping with appropriate heteroatoms is a powerful way of increasing visible light absorption of wide‐bandgap metal oxide photocatalysts, the incorporation of heteroatoms into the photocatalysts usually leads to the increase of deleterious recombination centers of photogenerated charge carriers. Here, a conceptual strategy of increasing visible light absorption without causing additional recombination centers by constructing an ultrathin insulating heterolayer of amorphous boron oxynitride on wide‐bandgap photocatalysts is shown. The nature of this strategy is that the active composition nitrogen in the heterolayer can noninvasively modify the electronic structure of metal oxides for visible light absorption through the interface contact between the heterolayer and metal oxides. The photocatalysts developed show significant improvements in photocatalytic activity under both UV–vis and visible light irradiation compared to the doped counterparts by conventional doping process. These results may provide opportunities for flexibly tailoring the electronic structure of metal oxides.