Ozone formation with (V)UV-enhanced dielectric barrier discharges in dry and humid gas mixtures of O-2, N-2/O-2, and Ar/O-2

The effect of (V)UV illumination at 172 nm and 253.7 nm on ozone formation with dielectric barrier discharges in air-like mixtures of nitrogen/oxygen and argon/oxygen as function of the water concentration is presented. Altho ugh (V)UV at these wavelengths efficiently cleaves ozone, the ozone concent ration in a combined (V)UV/dielectric barrier discharge in oxygen-containin g gases is reduced only very little. This corresponds to an enhanced concen tration of atomic singlet oxygen, which, in presence of water, increases th e production of hydroxyl radicals. This is confirmed by measurements of the removal rates of 2-propanol and of its byproducts in dry and humid air in a combined (V)UV/dielectric barrier discharge treatment.