Solar energy storage in the form of chemical bonds is of paramount relevance in the modern energy economy to increase the share of renewable energy utilization in moving to decarbonization. The ideal energy vector for the storage of solar energy is molecular H2 because of its high energy density and it can be produced from water splitting. However, photocatalysis has experienced five decades of hard struggle and solar-to-hydrogen conversion via photocatalysis remains very challenging due to great complexity of the catalytic processes sequentially occurring at different time scales.

The current scope of the heterogeneous photocatalysis design is based on a low-efficiency “trial-and-error” methodology that tremendously increases the workload of the research community. To overcome this challenge, multiscale modelling can provide a clear picture for “photocatalysis by design” from the viewpoint of mechanisms and guide us to select proper parameters. On the other hand, the limited instrumental characterization cannot completely fulfill the requirements for complex charge kinetics, particularly at the atomic and electronic scale. Indeed, theoretical investigations of photocatalysis have progressed rapidly alongside experimental attempts and met with great success. Based on nanoparticle crystal facet engineering I will describe different ways for tailoring the properties of realistic TiO2 nanoparticles (Figure 1). My goal is to show fundamental insights, dominating factors and structure-property relationships that will be further used to optimize the product outcome and to design enhanced photocatalysts.