Shape dependent photocatalytic H2 evolution of a zinc porphyrin

Dalton Trans. 2022 May 24;51(20):8009-8014. doi: 10.1039/d2dt00556e.

Abstract

Hydrogen is regarded as a promising molecular fuel in order to produce clean energy, thus it is of great importance to produce and store H2 in order to replace fossil fuels and to resolve the global energy and environmental problems. One strategy to produce hydrogen is the photocatalytic splitting of water. In this study different supramolecular architectures of a Zn(II) porphyrin, showing "flower", octahedral and "manta ray" shaped structures, were obtained using the "good-bad" solvent self-assembly protocol. More specifically, the bad solvent (methanol) was retained and the good solvent was alerted obtaining diverse assemblies. The different structures were studied by scanning electron microscopy, PXRD, UV-Vis and IR spectroscopies. The prepared structures were capable of proton reduction and production of molecular H2 in the presence of 5% w/w Pt-nanoparticles as catalysts and ascorbic acid as a sacrificial electron donor. Moreover, depending on the structure of the chromophore that is formed the amount of H2 produced varies. The maximum H2 production was obtained with the octahedral structures (185.5 μmol g-1 h-1).