X.L.Ma
,
N.G.Shang
,
C.S.Lee
,
S.T.Lee
材料科学技术（英文）
By Ar+ sputtering onto Si wafers which were surrounded by Mo plates, uniform cones over a large area on the Si surface were formed. Scanning electron microscopic study showed that the cones were formed on the entire surface of the Si wafer. The dimensions of the uniform cones were one micrometer in diameter and 5~6 micrometers high. They were further characterized by means of cross-sectional transmission electron microscopy, with the technique of micro-diffractions. It was found that the cone contained a pure Si regime and a Mo-rich regime. In the binary Mo-Si zone, we identified three distinct areas vertically: (1) domains of Mo-induced Si ordered structures, (2) a small volume of a new Mo3Si2 structural variant, intergrown with the Si ordered structure, and (3) a small amount of pure Mo nanoparticles covering the surface of the cones. The formation of the large and uniform cones may provide a new surface configuration for potential applications in surface science and technology.
关键词:
Si cones
,
null
,
null
Xifeng Lu Qilong Wang Deliang Cui
材料科学技术（英文）
g-C3N4/TiO2 composite were prepared by hydrolysis of Ti(OC4Hn 9 )4 and the precursors of g-C3N4 at room temperature and annealing in nitrogen atmosphere. X-ray diffraction results revealed that all the products were anatase structure. The chemical nature of O, N of the g-C3N4/TiO2 were identified by X-ray photoelectron spectroscopy, presenting N-Ti-O and N-Ti-N doping status of the composite. The g-C3N4/TiO2 composite showed better photocatalytic activity for the UV and visible-light degradation of Rhodamine B.
关键词:
Composite materials
,
Chemical synthesis
,
X-ray photoelectron spectroscopy (XPS)
杭祖圣
,
谈玲华
,
黄玉安
,
应三九
,
徐复铭
功能材料
在半封闭系统中采用直接热解三聚氰胺的方法制备了C3N4,XRD、XPS及元素分析的结果证明了产物是类石墨相C3N4(g-C3N4).用热分析(TG/DTG)研究了g-C3N4的热分解过程.通过迭代法计算了热分解反应活化能Ea,采用积分法结合36种动力学函数来判断g-C3N4热分解的机理函数.计算结果表明,g-C3N4的平均热分解活化能Ea为178.59kJ/mol,可能的动力学函数积分形式是g(a)=[-In(1-a)]4,指前因子A为21.67s-1,对应的热分解动力学方程为:dα/dT=(21.67/β)exp(-178.59×103/RT)×1/4(1-α)[-ln(1-α]-3
关键词:
非等温热重法
,
g-G3N4
,
热分解动力学
,
迭代法
楚增勇
,
原博
,
颜廷楠
无机材料学报
doi:10.15541/jim20130633
利用光催化剂将太阳能转化为人类可以直接利用的能量，并用其解决地球资源的枯竭和生存环境的恶化是可再生清洁能源研究的一个方向。g-C3N4的独特结构赋予其良好的光催化性能，使之成为光催化领域的研究热点。目前在光催化领域， g-C3N4主要用于催化污染物分解、水解制氢制氧、有机合成及氧气还原。在实际应用中，为进一步提高 g-C3N4的光催化效果，科研工作者开发了多种改进方法，例如物理复合改性、化学掺杂改性、微观结构调整等。本文主要论述了 g-C3N4在光催化领域的应用以及光催化性能的改进方法，简要阐述了光催化和各种改进方法的机理，分析了目前g-C3N4在光催化领域面临的问题和挑战，展望了g-C3N4的应用前景。
关键词:
g-C3N4
,
光催化
,
改进方法
,
综述
郑小刚
,
杜京城
,
李子黎
,
付孝锦
,
由耀辉
,
刘勇
人工晶体学报
采用浸渍法制备不同掺杂量的负载型光催化剂Ni/g-C3N4,并考察其在可见光照下对亚甲基蓝的光降解性能.利用XRD、FT-IR、SEM、TEM、XPS、N2-sorption和ICP-OES等手段表征Ni/g-C3N4样品.研究表明,Ni/g-C3N4催化剂的光催化活性随着金属镍粒子掺杂量的增加而增大,随着亚甲基蓝浓度的增大而减小,其中金属镍掺杂量4.0wt%的样品4-Ni/g-C3N4表现出优异的光催化活性和光降解稳定性.这是由于4-Ni/g-C3N4样品的光降解过程中产生了超氧自由基、羟基自由基和空穴等活性物质,其中超氧自由基起主导作用.金属Ni0离子在光生电子作用下生成Ni2+,O2分子得到电子生成O2·-自由基.这些活性物质的产生有助于光生电子-空穴对的分离和抑制其复合速率,从而实现可见光下高效催化降解亚甲基蓝.
关键词:
Ni/g-C3N4
,
掺杂效应
,
亚甲基蓝
,
光降解性能
姚光远
,
黄伟欣
,
李春全
,
孙志明
,
郑水林
无机材料学报
doi:10.15541/jim20160004
以水洗高岭土为载体,采用盐酸对g-C3N4进行质子化处理,通过浸渍法制备了g-C3N4/高岭土复合光催化材料.采用X射线衍射(XRD)、场发射扫描电镜(FESEM)和紫外-可见吸收光谱(UV-Vis)等手段对复合材料的晶体结构、微观形貌和光学性能进行了表征,并以罗丹明B为目标降解物,研究了复合材料在可见光下的光催化性能.结果表明:当高岭土和g-C3N4的质量配比为6∶3时,g-C3N4/高岭土具有较优的光催化性能,其光催化速率是纯g-C3N4的8.62倍;高岭土和g-C3N4通过静电吸引力紧密结合在一起,该复合结构能够有效地降低光生电子和空穴的复合几率,改善了纯g-C3N4光催化材料的吸附性能,进而有效提高了其光催化性能.
关键词:
高岭土
,
g-C3N4
,
可见光光催化
,
浸渍法
祝佳鑫
,
李志浩
,
周鹏
,
王辉虎
,
陈钊
,
彭大硌
,
芦佳
,
董仕节
中国有色金属学报
利用二氰二胺与尿素的复合粉末作为前驱体,通过简单的高温烧结法制备石墨相g-C3N4光催化剂.采用XRD、FESEM、TEM、BET、XPS和DRS等分析手段对g-C3N4的微观结构进行表征,并考察尿素加入量、催化剂浓度、染料初始浓度、溶液pH值以及光源等对光催化降解甲基橙的影响.结果表明:复合粉末前驱体所制备的g-C3N4具有典型的多孔结构,相比于纯二氰二胺或纯尿素所制备的产物具有更高的比表面积.随着尿素含量增加,g-C3N4产物的禁带宽度逐渐增大,而其表面的C和N摩尔比则从0.70降至0.60.可见光光催化降解甲基橙的实验结果显示随着尿素含量的增加,g-C3N4的光催化活性也随之增强,表明g-C3N4的表面化学组成及其氧化还原能力对可见光光催化活性起主要作用,而比表面积起次要作用.
关键词:
g-C3N4
,
甲基橙
,
尿素
,
二氰二胺
,
光催化
International Journal of Hydrogen Energy
A highly active photocatalyst based on g-C(3)N(4) coated SrTiO(3) has been synthesized simply by decomposing urea in the presence of SrTiO(3) at 400 degrees C. The catalyst demonstrates a high H(2) production rate similar to 440 mu mol h(-1)/g catalyst in aqueous solution under visible light irradiation, which is much higher than conventional anion doped SrTiO(3) or physical mixtures of g-C(3)N(4) and SrTiO(3). The improved photocatalytic activity can be ascribed to the close interfacial connections between g-C(3)N(4) and SrTiO(3) where photo-generated electron and holes are effectively separated. The newly synthesized catalyst also exhibited a stable performance in the repeated experiments. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
关键词:
Carbon nitride;Photocatalyst;Visible light;SrTiO(3);tio2 nanotube photocatalyst;hydrogen-production;water;generation;oxynitride
