Photocatalytic Application of Zinc Oxide Nanowires for Green Space Exploration
- Paper number
IAC-13,D4,P,1.p1,x17196
- Author
Mr. INNOCENT UDOM, University of South Florida, United States
- Year
2013
- Abstract
Of particular interest for space missions is the potential applicability of photocatalysis for the decomposition of organics in order to mitigate potential health and environmental problems in the controlled environment of a spacecraft or space station, particularly for long-term manned missions. One resource common to all manned missions in the immediate future is an abundance of sunlight, which presents an opportunity to use concentrated sunlight, through the use of solar concentrators, to possibly enhance or augment photocatalytic process(es). Among the various technologies, the potential applicability of photocatalysis, to decompose organic waste and inactivate a wide range of harmful microorganisms to benign products, is of a particular interest and viable solution. Although TiO2 a commonly studied photocatalyst, ZnO is found to be an alternative nanomaterial semiconductor for photocatalyst because of lower commercial cost and higher efficiency. The solar energy utilization efficiency could be improved by modifying the ZnO nanowire through doping of transition metals. In this work, ZnO nanowires were doped with silver on glass substrate through hydrothermal method and screened for the decomposition of methyl orange, MO (a model contaminate) under UV and visible irradiation. Characterization of the synthesized doped photocatalysts were performed using scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) for morphology and crystallinity, respectively. Brunhauer, Emmettt and Teller (BET) analysis measured mass-specific surface area; while UV-Vis absorbance spectra were acquired using Fourier transforms infrared spectroscopy (FTIR). Photocatalytic performance of ZnO and ZnO/Ag nanowires were obtained and compared to P25 titanium oxide (TiO2) for decomposition of MO. interestingly, in 2 hr ZnO and ZnO/Ag under UV irradiation revealed photodegradation efficiencies of 78% and 99%, respectively. Under visible light in 4hr, ZnO/Ag showed a superior photocatalytic activity similar to P25-TiO2. A potential deployment of photocatalytic technologies on a mission could be a reactor with modest enhancement in solar intensity brought about by a trough style reactor, with reactants and catalyst flowing along the axis of the trough and therefore being illuminated for a controlled duration based on the flow rate.
- Abstract document
- Manuscript document
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