Abstract

Green Synthesis of Zinc Oxide and Hydrogenated Zinc Oxide Catalysts

Author(s): James D Onubun, Joshua L Konne and Grace A Cookey

A novel green synthesis of zinc oxide catalysts using zinc nitrate, aqueous extract of plantain peel ash (for ZnO-PT control experiment) with hydrogen gas (for hydrogenated zinc oxide, ZnO-PTH) has been reported. The samples were characterized using XRD, SEM, EDS, UV and FT-IR. The XRD patterns of both samples showed characteristic reflections of ZnO with broader background for ZnO-PTH. Particle size estimations gave 50.67 and 52.93 nm for ZnO-PT and ZnO-PTH respectively. The SEM micrographs of ZnO-PH showed porous monophasic rod-like and rectangular polycrystallite plates while ZnO-PTH appeared largely biphasic (greyish and cloudy-patches) with larger pores. The EDS analysis showed Zn contents of both phases as approximately 50% and 56% in ZnO-PT and ZnO-PTH respectively. The UV-Vis of ZnO-PT nanoparticles in ethanol also showed different strong absorption bands at 310 nm, 330 nm and 360 nm while ZnO-PTH showed only at 320 nm in the UV region and two others at 580 nm and 620 nm in the visible region. Similarly, the FT-IR showed decrease in the wave number of bands (blue shift) for corresponding ZnO-PTH bands due to hydrogenation that caused ligand-metal charge transfer (LMCT). The results confirmed the formation of Zn1-xO (ZnO-PT) and ZnO1-x (ZnO-PTH) phases respectively.