5. Maximum performance for solar hydrogen production

The models outlined in this document are far from being sufficiently advanced by the scientific community to be applied to any photoreactive system and to predict optimum performance with an associated technology optimized for a given catalyst (inverse design). What's more, there are a huge number of different photocatalytic systems and technologies available today, with performance levels varying by more than two orders of magnitude, yet there is no lack of interest in the least efficient systems (which often offer more attractive long-term durability). Attempting to compare and discuss all the performances reported in the literature would be a titanic task, and would not bring any interesting new conclusions, other than those presented by the analysis of technologies and the catalysis and engineering hurdles in the course of this article. On the other hand, it is interesting to discuss...