Study of nitric oxide degradation properties of photoactive concrete containing nitrogen and/or carbon co-modified titanium dioxide – preliminary findings

In recent years, titanium dioxide (TiO2) has been commonly applied in the production of photoactive concrete materials capable of degrading a wide range of air contaminant such as nitric oxide (NO), VOC etc. It was confirmed that the photocatalytic activity of TiO2 can be further enhanced by modifying the photocatalyst with non-metals such as nitrogen (N) or carbon (C). In view of this finding, several concrete/TiO2 composites consisting of commercial concrete and raw anatase TiO2 (supplied by Grupa Azoty Zakłady Chemiczne ‘POLICE’ S.A., Poland), previously modified with ammonia [N source] and/or 2-propanol [C source] have been manufactured. For reference, the additional concrete samples were prepared, containing unmodified TiO2 and commercial titania P25 (Evonik). The NO degradation properties of prepared photoactive concrete materials were evaluated using laboratory test set-up. The measurements were conducted under constant temperature and humidity conditions, using ultraviolet light irradiation. Significant NO removal was recorded for the TiO2/concrete composites containing N and/or C co-modified titania. The results were related to the improved photocatalytic activity of modified photocatalysts and probable, partial NO reduction to N2, via the selective catalytic reduction process catalysed by TiO2.