Morphology-Controlled Synthesis and Metalation of Porphyrin Nanoparticles with Enhanced Photocatalytic Performance

Abstract

The design and engineering of the size, shape, and chemistry of photoactive building blocks enables the fabrication of functional nanoparticles for applications in light harvesting, photocatalytic synthesis, water splitting, phototherapy, and photodegradation. Here, we report the synthesis of such nanoparticles through a surfactant-assisted interfacial self-assembly process using optically active porphyrin as a functional building block. The self-assembly process relies on specific interactions such as π-π stacking and metalation (metal atoms and ligand coordination) between individual porphyrin building blocks. Depending on the kinetic conditions and type of surfactants, resulting structures exhibit well-defined one- to three-dimensional morphologies such as nanowires, nanooctahedra, and hierarchically ordered internal architectures. Specifically, electron microscopy and X-ray diffraction results indicate that these nanoparticles exhibit stable single-crystalline and nanoporous frameworks. Due to the hierarchical ordering of the porphyrins, the nanoparticles exhibit collective optical properties resulted from coupling of molecular porphyrins and photocatalytic activities such as photodegradation of methyl orange (MO) pollutants and hydrogen production.

Novel Supramolecular Photocatalyst Based on Conjugation of Cucurbit[7]uril to Non‐Metallated Porphyrin for Electrophotocatalytic Hydrogen Generation from Water Splitting

“…Due to its high molar absorptivity, dual‐absorption band feature and high charge carrier mobility, the electron migrations are believed to be facilitated, thus reducing the risks of photogenerated electron‐hole pairs recombination . In this regard, self‐assembled porphyrin derivatives in the form of nanoparticles, nanowires and nanorods as well as the composite of porphyrin‐based porous covalent organic framework with TiO 2 , porphyrin‐based imine gels and cobalt porphyrin‐polypyridyl surface coatings were utilized as visible‐light triggered photocatalysts in the hydrogen production from water splitting.…”

“…Due to its high molar absorptivity, dualabsorption band feature and high charge carrier mobility, the electron migrations are believed to be facilitated, thus reducing the risks of photogenerated electron-hole pairs recombination. [6b,c] In this regard, self-assembled porphyrin derivatives in the form of nanoparticles, nanowires and nanorods [9][10][11] as well as the composite of porphyrin-based porous covalent organic framework with TiO 2 [12] , porphyrinbased imine gels [13] and cobalt porphyrin-polypyridyl surface coatings [14] were utilized as visible-light triggered photocatalysts in the hydrogen production from water splitting.Herein, we report the synthesis of a novel photoactive supramolecular assembly that is based on the conjugation of cucurbit[7]uril hosts to free-base porphyrin core (TTP-4CB7) (Scheme 1) and also demonstrate the use of this assembly as a photocatalyst in hydrogen production from water splitting. Cucurbit[n]uril is a macrocycle and can be found in various sizes depending upon the number of glycol units which is composed of.…”

Donor–Acceptor Cyanocarbazole‐Based Supramolecular Photocatalysts for Visible‐Light‐Driven H2 Production

“…Among the few supramolecular photocatalysts reported to date, the widely used metal‐containing porphyrin systems have excellent properties for H 2 production, whereas metal‐free porphyrin systems exhibit relatively low performance. However, the metal components limit practical application because of their toxicity, high cost, and complex synthesis process . Zhu and co‐workers developed a noncovalent self‐assembled perylene‐3,4,9,10‐tetracarboxylic diimide (PDINH) supramolecular system, consisting solely of organic molecules, used for photocatalytic oxygen generation and photodegradation.…”

“…We then carried out solution‐state NMR spectroscopy on the sample dissolved in CDCl 3 [ δ =7.81 (d, J= 7.2, 4 H), 7.12–7.15 (m, 4 H), 7.07–7.10 (m, 8 H), 8.33 ppm (s, 2 H)] after the photocatalytic reaction to further demonstrate its stability. The overall photocatalytic performance, AQE, and stability of the 2CzPN supramolecule were much better than most reported supramolecular photocatalysts, such as fluorescein, Zn‐metallized porphyrin, Zn/Sn porphyrin, and 1D porphyrin nanostructures (Figure E). Moreover, its metal‐free structure also provides an advantage over metal‐based porphyrin supramolecular systems.…”

Fluorescein supramolecular nanosheets: A novel organic photocatalyst for visible-light-driven H2 evolution from water

“…The supramolecules withflexible skeletal structure through the different molecular self-assembly patterns have larger conjugated structure, more efficient charge transfer and separation, and broader absorption range than single molecule and polymer [21,22]. Among very few supramolecular photocatalysts, although the widely reported metal-contained porphyrin hybrids have good photocatalytic performance for H 2 production, metal-free porphyrin systems present a relatively poor activity, the metal composition confines their further applications due to high cost, metals toxicity and complicated preparation process [23,24]. Recently, Zhu and co-workers [25] reported a non-covalent selfassembled perylene-3,4,9,10-tetracarboxylic diimide (PDINH) supramolecular composed of metal-free organic molecules, working as a visible-light photocatalyst for O 2 production and photodegradation.…”