This project focuses on investigations of new low environmental impact photocatalysts for hydrogen production and water purification. The project is aimed at providing a theoretical framework for the mechanisms of the action of the materials. The goal is to understand the mechanisms of action of photocatalysts based on abundant materials so that these can be designed based on descriptors obtained at the atomic scale and their performance improved. The descriptors will be used in the implementation of a rational design strategy. The materials to be studied are based on TiO2 and the inclusion of co-catalysts and how these affect the performance of the bas material will be investigated. This work is aimed at complementing the fabrication of the photocatalysts with inkjet printing as recently published by our group [1]. The computations here described are an essential proof of concept of the combined experimental-computational methodology in order to extent this project to a large scale activity and attract large funding from the European Commission among others. [1] https://chemistry-europe.onlinelibrary.wiley.com/doi/full/10.1002/cptc.202100212