二维石墨相氮化碳纳米片的制备及其光催化性能

利用水热反应法将三聚氰胺悬浊液在200℃下反应生成中间产物,中间产物经煅烧直接制成了二维石墨相氮化碳(g-C3N4)纳米片(WCN),并与本体g-C3N4(CN)、传统热氧剥离法得到的g-C3N4纳米片(OCN)进行了比较.采用SEM、XRD、FTIR、Raman、AFM、PL对样品进行了表征,探讨了其光电化学性能和光催化性能.结果表明,两种方法均实现了对CN的剥离,WCN和OCN与CN的晶体结构和组成相同,WCN和OCN比表面积分别是CN的3.6倍和3.1倍.光电化学分析显示,WCN具有更好的载流子迁移与分离效率,具有较好的光催化活性.可见光照射下,WCN对亚甲基蓝(MB)的光催化降解率达到82.0％,分别是OCN和CN的2.4倍和6.7倍,光催化降解过程符合一级动力学方程.WCN具有优良的稳定性和可重复利用性能.     

超薄氧掺杂g-C3N4纳米片的制备及其光催化性能

采用H2SO4与KMnO4为氧化剂，通过对热聚合法合成的原始石墨相氮化碳（g-C3N4）超声辅助氧化剥离，制备了超薄氧掺杂g-C3N4纳米片。基于HRTEM、XRD、AFM、XPS表征，考察了超声辅助氧化剥离对原始g-C3N4形貌、结构的影响；通过可见光催化降解刚果红分析了超薄氧掺杂g-C3N4纳米片的光催化性能；通过UV-vis-DRS、EIS、PL分析，探究了超薄氧掺杂g-C3N4纳米片光催化性能的增强机制。结果表明，对原始g-C3N4超声辅助氧化剥离6 h，可获得比表面积为58.45 cm2 g-1、厚度为1.08 nm的超薄氧掺杂g-C3N4纳米片；超薄氧掺杂g-C3N4纳米片（200 mg L-1）对刚果红（20 mg L-1）在120 min内可实现83%的降解，具有良好的光催化性能；与原始g-C3N4相比，超薄氧掺杂g-C3N4纳米片更有利于催化活性位点的暴露与光生载流子的分离传输，从而具有更好的光催化性能。     

加热温度对尿素水溶液制备类石墨相氮化碳的影响及其机理EI北大核心CSCD

石墨相氮化碳（g-C3N4）由于其优异的化学稳定性和独特的电子能带结构被认为是一种廉价且极具潜力的光催化剂,然而传统方法制备的g-C3N4存在比表面积小、光生电子–空穴复合严重及剥离效率低等问题。采用尿素溶于一定量的水中,通过控制一定的升温速率及加热温度制备性能优异的g-C3N4。结果表明,在水中450~500℃裂解尿素可获得疏松多孔、类石墨相的g-C3N4纳米片,在500℃时获得的g-C3N4具有较多的纳米孔隙及较大的比表面积;550℃时孔隙消失,且g-C3N4的带隙能随着加热温度升高逐渐降低。光催化结果表明,随水中裂解尿素温度升高,制备的g-C3N4在可见光下对罗丹明B的降解率先增大后减小,500℃时降解率最高,达到75.5%,且明显好于500℃时直接加热尿素制备g-C3N4的降解率（24.1%）。多孔、少层且高比表面积的类石墨烯微观结构是500℃下获得多孔g-C3N4样品较高的光催化活性的主要原因,h＋和·O2–是参与降解反应的主要活性基团。     

g-C3N4/ZnO复合材料的制备、表征及可见光催化性能

以一步法原位合成了g-C3N4/ZnO异质结复合材料,评价其在可见光下降解亚甲基蓝（MB）的光催化活性,并探讨了g-C3N4/ZnO的光催化机制。运用XRD、FT-IR、SEM和UV-Vis DRS对所合成的复合材料进行表征。结果表明,经复合后g-C3N4和ZnO紧密结合,构建了异质结,提高了光生电子-空穴的分离效率,并且在可见光区表现出较强的光响应性;当g-C3N4的质量分数为19%时,复合材料降解MB的反应速率常数为0.0206min-1,是纯g-C3N4的3.8倍。催化剂重复使用5次,仍保持较高的催化活性。     

g-C3N4/ZnO复合光催化剂的制备及其可见光光催化性能的研究

采用缩聚法合成了类石墨氮化碳(g-C3N4),并与商品ZnO复合得到新型复合光催化剂g-C3N4/ZnO。采用XRD、SEM和UV-vis DRS对催化剂进行了表征。以300 W的卤钨灯为光源(λ>420 nm),以罗丹明B(RhB)为目标降解物进行了光催化实验。结果表明,与单纯的ZnO和g-C3N4相比,g-C3N4/ZnO复合催化剂的光催化性能有所提高,其中g-C3N4含量为7.0 wt%时光催化性能最好。     

Zr掺杂g-C3N4光催化降解有机污染物

以盐酸胍为前驱体，硝酸锆为锆源，通过热聚合法制备了Zr掺杂的Zr/g-C3N4光催化剂。运用XRD、SEM、UV-Vis DRS、PL、XPS、BET等手段对催化剂的结构、形貌、光学性能进行了表征分析。结果表明：Zr掺杂改性的Zr/g-C3N4光催化剂拓宽了可见光的吸收，增大了比表面积，且降低了光生电子-空穴的复合率，具有较好的光催化活性。可见光照射下，在60 min内，5Zr/g-C3N4对罗丹明B（RhB）的光催化降解率达99.29%，光催化降解过程符合一级动力学方程，其速率常数k= 0.08647 min-1，是纯g-C3N4的8.3倍。捕获剂实验发现降解RhB的主要活性物种为超氧自由基，并推测了可能的反应机理。     

g-C3N4/TiO2光催化复合材料光催化活性提升路径研究

由于g-C3N4存在着表面积小、光生载流子复合严重等问题,限制了光催化材料的光催化活性,故以g-C3N4/TiO2光催化复合材料为实验对象,提出g-C3N4/TiO2光催化复合材料光催化活性提升路径研究.选取适当的实验试剂与仪器,并对试剂进行一定的处理,制备g-C3N4纳米片、TiO2纳米片与g-C3N4/TiO2光催...     

纳米片层状类石墨氮化碳的制备及其光催化性能（英文）

以三聚氰胺为原料,采用热缩聚合成法,结合酸、热刻蚀协同改性工艺,制备了二维纳米片层状类石墨氮化碳(g-C3N4)。通过X射线衍射、扫描电镜、透射电镜、红外光谱、X射线光电子能谱、Raman光谱对试样进行了物相组成、显微形貌与分子结构表征。采用BET法分析了试样的比表面积,采用紫外–可见漫反射光谱、Mott–Schottky曲线分析了试样的可见光吸收性能与能带结构。通过可见光降解罗丹明B染料与盐酸四环素溶液,评估了试样的可见光催化性能。结果表明:采用热刻蚀改性剥离时,当三聚氰胺与NH4Cl的摩尔比为5:4时,所制备的纳米片层状g-C3N4厚度为47 nm,比表面积为22 m2/g,可见光催化降解性能提高显著,相比未经过改性处理的g-C3N4,其降解效率提高了3.4倍;4 h内对盐酸四环素溶液的降解率达到83.2%。     

Co3O4/g-C3N4复合光催化剂降解罗丹明B的研究

为提高石墨相氮化碳(g-C3N4)的光催化性能,采用3D花状ZIF-Co与g-C3N4混合热处理的方法制备了3D花状Co3O4/g-C3N4复合光催化剂,并将其用于光催化降解罗丹明B模拟染料废水。结果表明:当ZIF-Co与g-C3N4的质量比为5%时,制备的Co3O4/g-C3N4的光催化性能最佳,在可见光下照射30 min,其对罗丹明B的降解率可达90%以上,且该催化剂的重复稳定性好。在降解罗丹明B的过程中活性基团的作用顺序为·O2->h+>·OH。     

类石墨相氮化碳的制备及光催化还原CO2 性能研究

分别以尿素、三聚氰胺为前驱体,采用缩聚法制备不同形貌及性能的类石墨相氮化碳(g-C3N4)半导体催化剂,探究不同前驱体对催化剂的形貌及光催化还原CO2活性的影响。采用X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、紫外-可见光分光光度计（Uv-vis）、傅氏转换红外线光谱分析（FTIR）、比表面积测试（BET）、荧光光谱（PL）对所得g-C3N4进行各方面性能的探究,从而分析前驱体对所得产物性能的影响。实验结果表明,以尿素为前驱体制备出的g-C3N4在甲醇溶液中光催化还原CO2制备甲酸甲酯的产率 为512.8μmol/gcat•h ,以三聚氰胺为前驱体制备出的g-C3N4光催化产率为257.3 μmol/gcat•h。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。