Sustainable methods for the development of novel “green” roof tiles with enhanced photocatalytic performance

Abstract The introduction of eco-friendly nanomaterials capable of addressing environmental challenges in industrial applications has gained wide attention and encouraged strong collaborations between science and the public and private sectors. WHO and many governmental health organizations have highlighted the environmental and human health effects caused by exposure to nitrogen oxides (NOx) and especially nitrogen dioxide (NO 2 ). Vast research has highly investigated the adverse effects on human health after exposure to NO 2 and has profoundly recommended its mitigation in the emissions of various sources. This study proposes the development of a novel bioclimatic product in the form of a “green”, eco-friendly tile, with photocatalytic properties, able to degrade atmospheric pollutants, for subsequent use in roof tiles. To this aim, novel “green” roof tiles were developed based on the deposition of various crystallographic types of titanium dioxide (TiO 2 ) and the addition of two polymeric materials onto their upper surface. Experiments were conducted using nanoparticles of TiO 2 anatase, rutile, and a mixture of them along with the addition of Polyethylene glycol and Pluronic F-127. All types of newly developed nanomaterials were characterized using X-Ray diffraction analysis (XRD), particle size distribution analysis, the Brunauer-Emmet-Teller (BET) method, and Scanning electron Microscopy (SEM). Commercial ceramic roof tiles underwent spray-coating techniques, using the novel nanoparticles, followed by the investigation of their photocatalytic performance. The TiO 2 anatase samples with the addition of PEG exhibited the greatest specific surface area among all types of samples, thus indicating their high photocatalytic efficiency, which was also proved by subsequent photocatalytic experiments for the tiles sprayed with the same type of nanoparticles. The results reported in this study indicate that the novel cool and eco-friendly roof tiles prove to be ideal for the enhancement of environmental protection, the mitigation of air pollution and greenhouse gas emissions, and the reduction of the urban heat island phenomena.