摘要
采用一步法制备了还原氧化石墨烯(RGO)包覆ZnO纳米颗粒(NPs)的准核壳结构ZnO@RGO光催化复合材料.光催化实验表明,石墨烯的包覆使得ZnO@RGO对有机染料亚甲基蓝(MB)的光催化效率较ZnO NPs提高了10倍左右.透射电镜(TEM)和X射线衍射(XRD)表明,ZnO@RGO是由纤锌矿ZnO和石墨烯组成,且石墨烯包覆了颗粒尺寸约为6nm的ZnO.X射线光电子能谱(XPS)和拉曼谱(Raman)表明,石墨烯在ZnO中引入了应力及氧空位(VO).光致发光谱(PL)进一步表明,与ZnO纳米晶相比,ZnO@RGO的带间发射强度降低了约80%,并且出现了对应于VO的绿光发射峰.最后,根据上述实验结果提出了ZnO@RGO光催化活性增强的机理:石墨烯纳米片和界面应力作用所产生的氧空位对光生电子的高效协同俘获作用是导致ZnO@RGO具有高效光催化活性的内在原因.
The ZnO@ RGO quasi-core-shell composite photocatalyst ,where ZnO nanoparticles （NPs） were wrapped by graphene nanoshells , was prepared via a one-step method . Photocatalytic experiments indicated that the photodegradation efficiency of ZnO@ RGO on methylene blue （MB） increased by about 10 times compared to that of ZnO NPs .ZnO nanocrystals with the particle size of about 6 nm wrapped by RGO （reduced graphene oxide） nanosheets could be observed in transmission electron microscopy （TEM ） images .X-ray diffraction （XRD） patterns showed that the structure of ZnO was hexagonal wurtzite .X-ray photoelectron spectroscopy （XPS ） and Raman scattering manifested that there was strong interfacial interaction between ZnO and graphene which introduced about 3% interfacial stress and quantities of oxygen vacancies （VO ） . Photoluminescence （PL ） further evidenced the approximately 80% decrease in band-gap emission intensity in ZnO@ RGO compared with that in ZnO and the presence of interfacial VO. Finally ,the mechanism of the enhanced photocatalytic activity in ZnO@ RGO was proposed .The effective synergetic capture of graphene nanoshells and VO as a result of interfacial strain interaction improves the photocatalytic activities of ZnO based semiconductor photocatalysts .
基金
国家自然科学基金(U1332131)资助
关键词
氧化锌
光催化活性
纳米颗粒
石墨烯
降解
核壳
ZnO
photocatalytic activity
nanoparticle
graphene
degradation
core-shell
作者简介
杨晓喻，男，1989年生，硕士．研究方向：硬X射线吸收谱学．E-mail：yxiaoyu@mail．ustc．edu．cn
通讯作者：闫文盛，博士／副研究员．E-mail：ywsh2000@ustc．edu．cn
