Nanoelectrode Corona Discharges for Minimizing Ozone Emission from Indoor Corona Devices

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27 Σεπ 2011 (πριν από 5 χρόνια και 10 μήνες)

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Nanoelectrode Corona Discharges for Minimizing Ozone Emission from Indoor Corona Devices

Nanoelectrode Corona Discharges for Minimizing Ozone
Emission from Indoor Corona Devices
Z. Bo, K. Yu, G. Lu, S. Mao, J. Chen, and F.-G. Fan
University of Wisconsin-Milwaukee; Tongji University; Mechanical Engineering Sciences Laboratory (MESL)
Route
Route

Carbon nanotubes (CNTs) as the electrodes

Graphene sheets rolled-up into cylinders

High aspect ratio, high electrical conductivity, good
chemical stability, superior mechanical strength and durability

Smaller number of electrons and plasma volume
Introduction
Introduction
Electrostatic devices Inside corona system
Ozone
If
at excessive concentration
levels in poorly ventilated areas
Respiratory system
Lung function

FDA, OSHA, NIOSH and EPA have
proposed/improved regulations or health
recommendations to limit ozone emission
Acknowledgements:We acknowledge the financial support from National Science Foundation (CBET-0741336), Xerox Corporation, University of Wisconsin System, and UWM Research Growth Initiative. The authors thank H. A. Owen for technical support with SEM, A. Ash for
technical support with ozone analyzer, and A. V. Skliarov for technical support with Raman. Z. Bo acknowledges the research fellow support from the UWM Research Foundation.
Experimental
Experimental
Ozone emission
Ozone emission

Nanoscale electrodes are prepared by drop casting well-
dispersed CNT/ethanol suspension onto the substrate

The substrate is a holey carbon film coated copper TEM grid

CNTs: ~20 nm in diameter and ∼2.5 μm in length

Holes in the substrate: around 1 ~ 3μm

Discharge is from the side surfaces of the suspended CNTs
Electrical measurements
Electrical measurements

Corona discharge from CNTs can initiate and operate at a
much lower voltage due to the small electrode diameter, and is
thus energy-efficient

There is an optimum CNT length (CNT loading) that
maximizes the surface current density
J-V curve
Supply voltage for the same current density

Obvious ozone generation from tungsten wire discharges

For a given surface current density, the ozone generation
decreases with the decreasing wire size

No ozone (below the detection limit of 0.5 ppb) from CNT
discharges for surface current densities up to 0.744 A/m
2
Positive discharges Negative discharges
Stability
Stability

CNTs show good chemical stability after 30 min discharge
cycle
Raman spectra of the CNT electrode
Conclusion
Conclusion

Energy-efficient (lower corona initiation voltage) and
environmentally friendly (near-zero ozone emission)
corona discharge through the use of CNTs as discharge
electrodes is promising for practical applications in indoor
electrostatic devices.
MESL
10th Annual SyracuseCoE Symposium on Environmental & Energy Systems, Oncenter, Syracuse, NY, 9/27-28, 2010