Finding a way to clean the environment from the current pollution levels has become one of the most important matters throughout the past years. As it has been shown during the confinement due to Coronavirus, the moment a city slows down or stops its activity, contamination starts to decrease noticeably. But once the activity is retaken, there needs to exist a solution that prevents pollution levels from becoming a risk for the health. Current methods for cleaning air pollution are focused on filtering indoor air for workplaces or households. Some brands are investing on the use of photocatalysis to perform this indoor air cleaning, thanks to its great advantages and its average cost. Photocatalysis can also be used on the elimination of outdoor pollutant particles, but it is still under study. The aim of this work is to optimise the geometry of a photocatalyst whose function would be to eliminate VOC pollutant particles, by being displayed on the facades of buildings. The photocatalyst would only need sunlight as energy source and therefore, it would become a clean method for reducing contamination. In this project, three types of geometries have been studied, each with different parameters. The efficiency of each geometry has been calculated as the total amount of light impacting on the photocatalyst, which is translated as the amount of energy transferred to the photocatalyst and will be used for the photocatalytic process. I