6. Conclusions – Outlook

After presenting the considerable interest in developing renewable technologies to produce easily storable chemical fuels (currently accounting for over 70% of the world's final energy consumption), this article focuses on the production of solar-generated hydrogen by artificial photosynthesis. The two main obstacles to the development of this technology, which are the subject of intense research and will be at the heart of tomorrow's advances, were presented and analyzed. Firstly, there is the chemical challenge of developing efficient, stable and inexpensive photocatalysts for water oxidation and proton reduction. Another challenge, this time in process engineering and energy, concerns the development of prototypes and solar demonstrators with high kinetic and energy efficiency, which can be scaled up to reach industrial maturity. Two technologies coexist, but it is not yet clear whether...