= 아 래 =
1. 일 시 : 2013. 4. 16 (화), 16:00 ~
2. 장 소 : 응용공학동 1층 영상강의실
3. 연 사 : 이선영 교수 (한양대학교 재료공학과)
4. 제 목 : Fabrication of reduced graphene oxide and CdS nanoparticles
sensitized ZnO nanostructure composites for effective removal of organic pollutants
Zinc oxide (ZnO) composites with reduced graphene oxide nanosheets (RGO) and cadmium sulfide (CdS) nanoparticles are crucial in developing efficient photocatalytic device under visible light. ZnO is applicable in photocatalyst because of its high electron mobility at room temperature and it’s easier to grow various nanostructures. For graphene, it exhibit high electrical conductivity, large surface area and high adsorption properties which can boost catalytic performance. However, the wide band gap of ZnO limits absorption of solar spectrum in UV region. Hence, in order to expand band gap energy from UV to visible range, sensitization of CdS nanoparticles was performed. Moreover, whole solar spectrum using CdS nanoparticles with different sizes can be captured due to its quantum size effect. In this work, we have sensitized chemically grown nanorods of ZnO with RGO and CdS using chemical bath deposition method in single step. The fabricated nanocomposites were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and optical absorbance. The peaks corresponding to ZnO, CdS and graphene in diffraction pattern revealed successful formation of nanocomposites. Moreover, Raman shifts at 439 cm-1(E2mode),1353cm-1(Dbandofgraphene)1589cm-1(Gbandofgraphene)and607cm-1(CdS)indicatedsuccessfulformationsofZnO,CdSandreducedgraphenenanocomposites.Thesynthesizednanocompositeswereusedtodegrademethyleneblue(MB)undervisiblelighttoevaluateitsphotocatalyticactivity.Itwasalso found that RGO-CdS-ZnO nanocomposites exhibit higher photocatalytic activity (99%) compared to ZnO-CdS (84%) only, which is attributed to effective charge separation and transportation of photo-electrons. Therefore, these nanocomposites can be used in various fields such as photocatalysis, solar cells, gas sensors, field emission and anti-bacterial activity.