Hierarchical TiO Layers Prepared by Plasma Jets.

Heterogeneous photocatalysis of TiO is one of the most efficient advanced oxidation processes for water and air purification. Here, we prepared hierarchical TiO layers (Spikelets) by hollow-cathode discharge sputtering and tested their photocatalytic performance in the abatement of inorganic (NO, NO) and organic (4-chlorophenol) pollutant dispersed in air and water, respectively. The structural-textural properties of the photocatalysts were determined via variety of physico-chemical techniques (XRD, Raman spectroscopy, SEM, FE-SEM. DF-TEM, EDAX and DC measurements). The photocatalysis was carried out under conditions similar to real environment conditions. Although the abatement of NO and NO was comparable with that of industrial benchmark Aeroxide TiO P25, the formation of harmful nitrous acid (HONO) product on the Spikelet TiO layers was suppressed. Similarly, in the decontamination of water by organics, the mineralization of 4-chlorophenol on Spikelet layers was interestingly the same, although their reaction rate constant was three-times lower. The possible explanation may be the more than half-magnitude order higher external quantum efficacy (EQE) compared to that of the reference TiO P25 layer. Therefore, such favorable kinetics and reaction selectivity, together with feasible scale-up, make the hierarchical TiO layers very promising photocatalyst which can be used for environmental remediation.