Visible light-sensitive photocatalytic aditives to render cement-based materials suitable depolluting agents

Abstract

The presence of NOx in the atmosphere is an environmental challenge that needs to be addressed. Good NOx removal efficiencies have been attained by photocatalytic activity of TiO2 under UV light. TiO2 has been incorporated to cement-based materials to obtain depollutant and self-cleaning building materials. With the aim of broadening the sensitivity of these materials towards the visible light, two doped photocatalytic additives based on TiO2 were synthesized and used. Flame spray pyrolysis (FSP) allowed us to obtain TiO2 doped with either Fe or V, which generated hole-electron pairs with band gaps corresponding to visible light. Fe-TiO2, V-TiO2 and plain TiO2 were added (up to 2.5 wt.%) to different binding matrices: Portland cement (OPC) and air lime. The effect of the three photocatalytic additives on the setting time, consistency and mechanical properties of the cements were assessed.