A nanobelt structure as a photocatalyst assembled from molecular cobalt complexes boosts hydrogen evolution

Homogeneous molecular catalysts suffer from formidable recycling and instability challenges, preventing their further application. In this paper, we report that thiophene substituted salen metal complexes could work as heterogeneous hydrogen evolution photocatalysts in the water phase after self-assembling into a supramolecular nanobelt by highly ordered π–π stacking, which exhibited semiconductor properties. Compared to the previously reported salen metal catalysts which need photosensitizers and organic solvents, the newly assembled catalyst serves as a photocatalyst in the water phase, and its hydrogen evolution rate is 55 times higher than that of its homogeneous system and 110 times higher than that of metal salen complexes without the thiophene group, and the stability is also greatly improved. The enhanced catalytic activity is revealed to be due to the great improvement of optical absorption, charge separation and interfacial charge transfer rates.