Design components of porphyrin-based photocatalytic hydrogen evolution systems: A review

It is widely recognised that renewable hydrogen will play a key role in our future energy mix. One approach is to use photocatalytic water-splitting devices for sustainable hydrogen generation. For these devices to function effectively, materials that can capture sunlight are essential. In this review porphyrins and their suitability as photosensitisers and/or proton reduction photocatalysts are discussed, both within homogeneous, heterogeneous and photo-electrochemical environments. In particular, the various parameters that can be varied will be compared, and also the difficulty in accurate comparisons, as there is no standard reporting approach. The photochemistry is further complemented by a systematic review of the use of electrochemistry in designing photocatalytic porphyrin based systems for hydrogen evolution.