Unraveling Structure-Performance Relationships in Porphyrin-Sensitized TiO2 Photocatalysts

Over the years, porphyrins have arisen as exceptional photosensitizers given their ability to act as chlorophyll-mimicking dyes, thus, transferring energy from the light-collecting areas to the reaction centers, as it happens in natural photosynthesis. For this reason, porphyrin-sensitized TiO2-based nanocomposites have been widely exploited in the field of photovoltaics and photocatalysis in order to overcome the well-known limitations of these semiconductors. However, even though both areas of application share some common working principles, the development of solar cells has led the way in what is referred to the continuous improvement of these architectures, particularly regarding the molecular design of these photosynthetic pigments. Yet, those innovations have not been efficiently translated to the field of dye-sensitized photocatalysis. This review aims at filling this gap by performing an in-depth exploration of the most recent advances in the understanding of the role played by the different structural motifs of porphyrins as sensitizers in light-driven TiO2-mediated catalysis. With this goal in mind, the chemical transformations, as well as the reaction conditions under which these dyes must operate, are taken in consideration. The conclusions drawn from this comprehensive analysis offer valuable hints for the implementation of novel porphyrin-TiO2 composites, which may pave the way toward the fabrication of more efficient photocatalysts.

Automated summary

Porphyrins have been widely used as photosensitizers in the field of photovoltaics and photocatalysis due to their ability to transfer energy from light-collecting areas to reaction centers, similar to natural photosynthesis. However, while solar cell development has led to continuous improvement in the molecular design of these pigments, these innovations have not been efficiently applied to dye-sensitized photocatalysis. This review aims to explore recent advances in the role of porphyrin structural motifs as sensitizers in TiO2-mediated catalysis, providing valuable insights for the development of more efficient photocatalysts.