Unraveling Structure–Performance Relationships in Porphyrin-Sensitized TiO2 Photocatalysts

Abstract

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.

Phase Transformation Strategies for the Construction of Heterojunction TiO2 Photocatalysts

“…In recent years, the development of renewable green clean energy-hydrogen is considered to play an important role in solving the increasing energy shortage and environmental pollution problems. [1][2][3] Photocatalytic hydrogen production has been widely applied as a clean and efficient technology, which can realize the conversion of solar energy with lowdensity to chemical energy with high-density. [4] In order to improve the absorption of visible light and the separation efficiency of photogenerated carriers in the process of photocatalytic, the research of efficient photocatalysts is of great significance.…”

Sn(IV)porphyrin-Incorporated TiO2 Nanotubes for Visible Light-Active Photocatalysis

“…Additionally, their inherent aromatic electronic features, substantial flexibility in molecular framework, and rigid structural framework render them notably compelling as photosensitizers, distinguishing them from other optoelectronic materials [25][26][27][28]. In particular, porphyrin-sensitized TiO 2 hybrid materials have been proven to amplify the interfacial charge transfer, decrease electron-hole recombination rates, and improve photocatalytic performance via heterojunction interfaces [29][30][31][32][33][34].…”

Surface Modification of ZnO with Sn(IV)-Porphyrin for Enhanced Visible Light Photocatalytic Degradation of Amaranth Dye

“…However, some derivatives of porphyrin do not interact with the surfaces of inorganic metal oxides due to the absence of an anchoring group. Under these circumstances, the photocatalytic activity of the hybrid photocatalysts may be reduced because the proper electron transfer does not occur [ 27 , 28 , 29 , 30 ]. The removal of these barriers requires a surface modification through chemical bonding between metalloporphyrin and metal oxide [ 31 , 32 , 33 , 34 , 35 ].…”