Atmospheric NOx removal: study of cement mortars with iron- and vanadium-doped TiO2 as visible light–sensitive photocatalysts

Mortars made with Portland cement, two different calcium aluminate cements and air lime were chosen to incorporate photocatalytic additives, because they have large exposed surfaces that boost the photochemical oxidation (PCO) of atmospheric pollutants such as nitrogen oxides. TiO2 as reference catalyst, and two doped titania, Fe-TiO2 and V-TiO2, which were expected to increase the sensitivity of the additives towards the visible light, were studied. Cementing matrices, particularly air lime and high alumina cement mortars, yielded significant amounts of NO removal under the three illumination conditions studied (UV, solar and visible light), with high selectivity response for NO abatement (up to 60 to 80%) and low NO2 release. The presence of calcium carbonate has been shown to have a synergistic effect, enhancing the PCO of these mortars under different light sources