异质结构复合半导体光催化性能研究

半导体光催化技术是解决环境和能源等问题的有效途径之一。但传统的半导体催化剂存在禁带宽度较大,太阳能利用率较低,反应速率慢。通过半导体-半导体复合构造异质结构光催化剂是实现这一目的的有效手段。研究发现,异质结构的存在,可有效降低光生电子与光生空穴复合效率,提高光催化性能。结果表明,通过改变晶粒尺寸、离子掺杂、表面敏化与外场耦合等办法,可进一步提高光催化效率。     

TiO2制备改性及光催化应用研究进展

TiO2纳米粒子是一种N型半导体材料,因其具有高活性、稳定性、生物相容性而成为最受重视的一种光催化纳米材料,得到了广泛应用。但由于其存在禁带宽度较大,电子受激发跃迁时产生的电子和空穴十分容易复合等问题,影响光了催化效率,制约着其进一步发展。目前,如何提高TiO2纳米粒子的光催化效率成为材料研究中的热点,是研究的核心课题之一。本文介绍了TiO2纳米粒子的光催化原理,系统综述了TiO2纳米粒子的制备方法;同时总结了提高TiO2纳米粒子光催化效率的方法,并介绍其在生产生活中的应用。     

光催化剂TiO2改性的研究进展

TiO₂具有光催化性能好、化学性质稳定、毒性低、价格低廉等优点,但由于禁带较宽,只对紫外光有响应,且电子和空穴容易复合,导致光催化活性和效率降低。本文介绍了TiO₂的几种主要改性方法的最新研究进展。表面沉积贵金属、半导体复合、染料敏化可以降低TiO₂的禁带宽度,增加其响应波长,提高太阳光的利用率。离子掺杂可使得TiO₂晶体表面产生缺陷,抑制光生电子和空穴的复合,增加表面活性中心的数量。碳纳米管和石墨烯掺杂则能够提高TiO₂对可见光的吸收率,扩大光响应范围,同时加快电子传输,减少载流子复合,提高催化效率。指出石墨烯作为新型掺杂材料具有很大的发展潜力,TiO₂基多组分复合型光催化剂可获得比单种组分表面改性或者掺杂TiO₂更好的效果。最后介绍了TiO₂表面的亲/疏水改性研究进展。     

Cu2O光催化剂综述

介绍Cu_2O光催化降解机理,禁带宽度,光生载流子利用率和溶液pH影响Cu_2O光催化降解活性,通过掺杂,负载贵金属,碳材料修饰和半导体复合可提高Cu_2O光催化性能。     

金属和非金属掺杂二氧化钛纳米粒子的制备及应用研究进展

近年来,光催化领域的研究逐渐深入,TiO2作为一种环保廉价的光催化材料被广泛使用。纯TiO2的光催化活性受其禁带宽度的限制只能被紫外光激发,以及光生电子-空穴对复合几率高,光催化效率较低。如何有效提高TiO2的光催化效率,合成具有抑制光生电子-空穴复合且同时具有较窄能隙的TiO2材料成为研究重点。目前各类金属、非金属掺杂TiO2成为热门研究领域。本文综述了TiO2纳米材料的特点和结构,并系统归纳了常见金属、非金属掺杂TiO2纳米粒子的制备方法及其应用研究进展。     

碳基材料复合半导体光催化剂的制备及应用研究进展

半导体光催化剂被广泛地应用于光催化领域,但其常因自身的禁带宽度较大、量子效率较低、催化效率较低、与反应物接触几率较低等因素在实际应用中受到诸多限制。而碳基材料作为一类结构稳定的新材料,具有稳定性强、导电能力强、比表面积大、包含大量的吸附位点等特性,与光催化剂复合之后,能够有效减小其禁带宽度、降低其载流子的复合率并为其提供更多的吸附位点,很大程度上提高了光催化剂的光催化性能。该文章以石墨烯、碳纳米管、富勒烯以及碳纤维等碳材料与各类半导体光催化剂复合为例,综述了碳基材料与光催化剂复合的工艺、提高其光催化性能的机理、影响碳基材料改性程度的因素及其在产氢、杀菌等方面的应用,并且对其进行了展望。     

不同形貌的氧化镍的制备及应用研究

光催化技术因其广泛应用于析氢反应、降解水中污染物、CO_2还原反应等,因而在解决能源短缺和环境污染问题上有突出贡献。NiO是典型的p型半导体,但因其禁带宽度大,光生电子与空穴对易复合,阻碍了其在光催化领域的应用。通过与n型半导体复合及元素掺杂的方法可以解决上述问题,基于此,综述了NiO的制备以及光催化的研究进展。     

新型复合溴化氧铋光催化材料在废水处理中的研究进展

针对溴氧化铋可吸收利用可见光,具有良好的光学以及催化性能但单独的Bi OBr光催化效率不高的现状,结合近几年国内外研究进展,介绍了新型复合Bi OBr光催化材料的制备方法(非金属掺杂、金属掺杂、半导体复合和多种成分复合)。同时介绍了新型复合Bi OBr光催化材料在印染废水以及抗生素废水处理方面的研究进展。分析认为,进一步加强新型复合Bi OBr光催化材料稳定性及回收能力,与多种系统相结合,更广泛地用于废水处理中是今后的研究方向。     

新型复合溴化氧铋光催化材料在废水处理中的研究进展

针对溴氧化铋可吸收利用可见光,具有良好的光学以及催化性能但单独的Bi OBr光催化效率不高的现状,结合近几年国内外研究进展,介绍了新型复合Bi OBr光催化材料的制备方法(非金属掺杂、金属掺杂、半导体复合和多种成分复合)。同时介绍了新型复合Bi OBr光催化材料在印染废水以及抗生素废水处理方面的研究进展。分析认为,进一步加强新型复合Bi OBr光催化材料稳定性及回收能力,与多种系统相结合,更广泛地用于废水处理中是今后的研究方向。     

BiOI基复合光催化材料的研究进展

因其特殊的层状结构和合适的禁带宽度,BiOI显示出了优异的可见光光催化性能。通过半导体的复合制备BiOI基复合光催化材料来提高BiOI的光催化活性是当前BiOI光催化研究的主流。本文主要综述了BiOI基复合光催化材料的制备方法、结构、形貌以及光催化活性和机理的最新研究进展,并展望了其发展趋势。     

Design of NiS/CNTs nanocomposites for visible light driven catalysis and antibacterial activity studies

The outstanding photocatalytic activity of metal sulphide based photocatalysts have much attention in environmental remediation due to utilization of wide spectrum range. In present paper, the photocatalytic activity of NiS and NiS-CNTs (carbon nanotubes) nanocomposite has been investigated. The hydrothermal technique was used for synthesis of NiS and NiS/CNTs nanocomposite. Structural elucidation of NiS and NiS/CNTs nanocomposite was conducted by X-ray diffraction (XRD) and Fourier transform infra-red (FTIR) techniques. These characterization techniques verified the formation and purity of samples as extra peaks of impurities were not observed in the obtained data. Scherer formula was used to examine the crystallite size of NiS NPs and NiS/CNTs reported that 9.5 nm and 10.2 nm are sizes of NiS and NiS/CNTs respectively. Scanning electron microscopic (SEM) analysis revealed the reduction in the aggregation of NiS and improved the surface area to assist the redox reactions due to presence of CNTs. Current-voltage (I–V) measurements studied the electrical behaviour of photocatalysts. Optical measurements of synthesized samples were analysed by UV–Visible spectrophotometry. The improvement in bandgap energy of nanocomposite was main reason of excellent photocatalytic activity. About 96% degradation of methylene blue was recorded via NiS/CNTs nanocomposite within 50 min. Photocatalytic performance of nanocomposite is faster than individual metal sulphide due to production of more free radicals, Ni–S–C bond development, surface defects and availability of more reaction sites. These features improved the photocatalytic activity of NiS/CNTs and provide an evidence to use carbon nanotubes for the formation of metal sulphide nanocomposites. Antibacterial property of sample was investigated by four Gram negative bacteria (Proteus vulgaris, Klebsiella pneumonia, Escherichia coli and Pseudomonas aeruginosa) and one Gram positive bacteria (Staphylococcus aureus) at different concentrations using disc diffusion method. The possible mechanism for degradation of Methylene blue under UV–Visible illuminations has been discussed. The upgraded degradation of methylene blue by NiS/CNTs nanocomposite supported that it is promising material for treatment of wastewater.     

石墨烯制备中的无机氧化剂和无机还原剂

化学氧化还原法制备石墨烯具有原料来源广、成本低、产率高和容易扩大的特点,是工业化生产石墨烯的发展方向。综述了石墨烯制备中的无机氧化剂和无机还原剂及其作用原理和化学反应;从实际应用角度出发,提出了石墨烯制备中无机氧化剂和无机还原剂的改进方向,介绍了K₂FeO₄为代表的新型氧化剂和硅为代表的新型还原剂,以推进石墨烯及其复合材料的绿色制备。建议关注未来石墨烯产业发展对无机盐行业发展的带动作用;建议加强纳米石墨烯掺杂氧化物复合材料相关的应用基础研究。     

石墨烯及其复合材料的制备研究进展

石墨烯具有独特的物理化学性质,在很多领域都表现出良好的应用前景,得到了日益广泛的关注和研究。本文对石墨烯及其复合材料的制备方法进行了综述,并以石墨烯/量子复合材料、石墨烯/碳纳米管复合材料、石墨烯/Pd复合材料及石墨烯/聚醚砜导电复合材料的制备为例进行具体阐述。     

Improved photocatalytic performance in Bi2S3-ZnSe nanocomposites for hydrogen production

One way to improve the rate of hydrogen production from water-splitting reactions is by the separation of photogenerated carriers. This separation process can be achieved with narrow bandgap semiconductors. ZnSe has a 2.7?eV bandgap, but its photocatalytic activity is very low due to a high recombination rate of the photogenerated carriers. Therefore, a combination of Bi₂S₃ and ZnSe may potentially produce a visible-light-active photocatalyst, utilizing bandgap engineering and the p-n junction effect. ZnSe, Bi₂S₃ and Bi₂S₃-ZnSe nanocomposites were prepared by a hydrothermal method. Bi₂S₃ at different weight percentages (3–15?wt%) was decorated with ZnSe nanoparticles. The hydrogen evolution reaction was conducted in the investigation of ZnSe, Bi₂S₃ and Bi₂S₃-ZnSe photocatalytic efficiency. The results demonstrate that photocatalytic efficiency was highly affected by the Bi₂S₃ weight percent. The optimal weight percent for Bi₂S₃ was 15?wt%, at which the rate of hydrogen evolution was 2600?μmol?g^?1 h^?1 within 240?min in the presence of 1.2?g/L photocatalyst.     

天然橡胶复合材料制备及力学性能研究

分别以白炭黑、碳纳米管、碳微球及石墨烯为增强剂,对天然橡胶复合材料的制备以及其力学性能进行研究。采用传统机械混炼法将复合材料进行混合,通过平板硫化机进行交联制备天然橡胶复合材料。分别考察不同增强剂的含量对橡胶复合材料力学性能的影响,找到最佳的添加量。分析了不同种增强剂对复合材料力学性能的影响规律,对其增强效果进行对比说明。采用电子万能拉伸测试仪、邵氏硬度计对复合材料的拉伸性能和硬度性能进行分析,结果表明:复合材料的力学性能随着炭微球、碳纳米管和石墨烯含量的增加而增加,随着白炭黑的含量的增加而减少,碳纳米管和石墨烯的增强效果较好。     

Influence of doped platinum nanoparticles on photocatalytic performance of CuO–SiO2 for degradation of Acridine orange dye

Preparation of cupric oxide-silicon dioxide nanoparticles was carried out using a sol-gel method. Cupric oxide-silicon dioxide nanoparticles were decorated by different weight percent of platinum (0.5, 1.0, 3.0 and 5.0 wt %) using method of photoassisted deposition. XRD remarks revealed that XRD patterns for all samples are composed of cupric oxide. Therefore, silicon dioxide is amorphous and decoration of cupric oxide-silicon dioxide nanoparticles by platinum has no effect on the formed phase. Also, due to low percent of platinum there are no peaks for platinum oxide or platinum. Cupric oxide has bandgap energy absorb in visible region but has high e-h recombination rate. Decoration of cupric oxide-silicon dioxide nanoparticles by platinum was decreased bandgap energy from 2.38 to 1.91 eV and also decrease rate of e-h recombination rate. The photocatalytic activity of platinum decorated cupric oxide-silicon dioxide nanoparticles was measured under visible light for Acridine orange dye degradation. 100% of Acridine orange dye can be degraded using 3.0 wt % of platinum decorated cupric oxide-silicon dioxide photocatalyst, 1.2 g/L dose of platinum decorated cupric oxide-silicon dioxide photocatalyst and 30 min reaction time. 3.0 wt % of platinum decorated cupric oxide-silicon dioxide photocatalyst has photocatalytic stability for five times.     

超声雾化辅助微波法合成氧化锌纳米颗粒及其光催化性能

氧化锌(ZnO)具有宽带隙、高光催化效率和稳定的化学性质,已成为处理水体中有机污染物的常用材料。采用超声雾化辅助微波法成功合成了ZnO纳米颗粒,XRD图谱和TEM照片表明超声雾化抑制了ZnO结晶,其结构为无序状,得到的ZnO纳米颗粒为非晶态。非晶态ZnO纳米颗粒紫外最强吸收峰为300 nm,紫外吸收边发生红移,禁带宽度降至3.17 eV,紫外吸收率高于晶态ZnO颗粒,光催化活性显著提高,对Rhodamine B催化降解效率较晶态ZnO颗粒高出37%。超声雾化辅助微波法是一种低温、低能耗合成非晶态ZnO纳米颗粒的方法,合成的ZnO纳米颗粒光催化活性高,但其光催化效率随催化循环次数增加而降低,其分散性和稳定性有待进一步改善。     

Enhanced hydrogen production from aqueous methanol solution using TiO2/Cu as photocatalysts

The photocatalytic hydrogen production from aqueous methanol solution using titanium dioxide (TiO₂) was investigated in the addition of metal particles including copper, lead, tin, and zinc. The results show that only the addition of copper particles enhances the hydrogen production. The copper usage and reaction temperature were further optimized for TiO₂/Cu photocatalyts. Under the optimal conditions, the hydrogen production using TiO₂/Cu as photocatalysts is approximately 68 times higher than that obtained with only TiO₂.     

基于德温特专利数据的低维纳米碳材料发展态势文献分析

富勒烯、碳纳米管和石墨烯等低维纳米碳材料为近年来纳米材料和纳米技术领域的研究热点。本文以3种典型的低维纳米碳材料为研究对象,通过对德温特（Derwent）专利数据库收录的从2005—2015年专利受理数量、国家分布、专利权人名称、学科类别及国际专利分类代码等相关信息进行分析,发现近年来研发人员更加关注石墨烯,对碳纳米管和富勒烯的关注度在逐渐下降。经过对全球低维纳米碳材料技术创新现状与发展趋势的分析,指出我国低维纳米碳材料在进一步发展中还存着研发领域发展不均衡、缺乏全方位发展战略的整体布局研究、技术成果不能顺利转化、经费投入偏低等问题,并针对以上问题提出了建设性意见,以期为我国低维纳米碳材料相关领域的技术创新和决策提供参考。     

Carbon-based TiO2-x heterostructure nanocomposites for enhanced photocatalytic degradation of dye molecules

Application of brown titanium dioxide (TiO_2-x) and its modified composite forms in the photocatalytic decomposition of organic pollutants in the environment is a promising way to provide solutions for environmental redemption. Herein, we report the synthesis of effective and stable TiO_2-x nanoparticles with g-C₃N₄, RGO, and multiwalled carbon nanotubes (CNTs) using a simple hydrothermal method. Among all the as-synthesized samples, excellent photocatalytic degradation activity was observed for RGO-TiO_2-x nanocomposite with high rate constants of 0.075 min^?1_, 0.083 min^?1 and 0.093 min^?1 for methylene blue, rhodamine-B, and rosebengal dyes under UV–Visible light irradiation, respectively. The altered bandgap (1.8 eV) and the large surface area of RGO-TiO_2-x nanocomposite impacts on both absorption of visible light and efficiency of photogenerated charge electron (e^?)/hole (h⁺) pair separation. This resulted in enhanced photocatalytic property of carbon-based TiO_2-x nanocomposites. A systematic study on the influence of different carbon nanostructures on the photocatalytic activity of brown TiO_2-x is carried out.