Porphyrin-Based Supramolecular Self-Assemblies: Construction, Charge Separation and Transfer, Stability, and Application in Photocatalysis

Abstract

As a key means to solve energy and environmental problems, photocatalytic technology has made remarkable progress in recent years. Organic semiconductor materials offer structural diversity and tunable energy levels and thus attracted great attention. Among them, porphyrin and its derivatives show great potential in photocatalytic reactions and light therapy due to their unique large-π conjugation structure, high apparent quantum efficiency, tailorable functionality, and excellent biocompatibility. Compared to unassembled porphyrin molecules, supramolecular porphyrin assemblies facilitate the solar light absorption and improve the charge transfer and thus exhibit enhanced photocatalytic performance. Herein, the research progress of porphyrin-based supramolecular assemblies, including the construction, the regulation of charge separation and transfer, stability, and application in photocatalysis, was systematically reviewed. The construction strategy of porphyrin supramolecules, the mechanism of charge separation, and the intrinsic relationship of assembling structure-charge transfer-photocatalytic performance received special attention. Surfactants, peptide molecules, polymers, and metal ions were introduced to improve the stability of the porphyrin assemblies. Donor-acceptor structure and co-catalysts were incorporated to inhibit the recombination of the photoinduced charges. These increase the understanding of the porphyrin supramolecules and provide ideas for the design of high-performance porphyrin-based photocatalysts.

Keywords: application; intrinsic relationship between the supramolecular structure and property; mechanism for charge separation; porphyrin; supramolecular photocatalyst.

Figure 11

(a) The formation process of S-type heterojunction and the migration path of photogenerated carriers [102]; (b) Schematic diagram of the interface structure of bimetallic porphyrin heterojunctions [104]; (c) Photocatalytic charge transfer mechanism of CuTCPP/TS heterojunction [105].

Figure 16

(a) Schematic diagram of the synthesis of C-Z-T nanocomposites; (b) Hydrogen production rates of CdS Nps and composites under visible light [149]; (c) Mechanism diagram of D-A supramolecular photocatalyst; (d) Hydrogen production rate at the full spectrum of TPPS/C60 [151].

Figure 19

(a) Schematic diagram of TCPP/PDINH photocatalytic system; (b) Degradation rate of phenol with different photocatalysts under visible light [180]; (c) Schematic diagram of TCPP/BiOBr photocatalytic system; (d) Degradation rate of tetracycline with different photocatalysts under visible light [182]; (e) Degradation rates of methyl oranges under visible light by different photocatalysts [184]; (f) Degradation rate of rhodamine B under visible light by different photocatalysts [186].

Figure 1

Some approaches used to build up porphyrins [24].

Figure 2

Diagram of J-type and H-type porphyrin aggregates [47].

Figure 3

(a) TEM image of SnPyTriPP nanosheets on a Si(100) substrate [56]; (b) TEM image of PdTCPP nanoleaves [57]; (c) TEM image of PtTCPP nanoleaves; (d) SEM image of PdTCPP nanoribbon [58]; (e) ZnTCPP self-assembles to highly ordered nanofilms; (f) SEM image of a film of ZnPor-INs transferred from the water [59].

Figure 4

(a) Co-assembly of oppositely charged porphyrins to form porphyrin supramolecular nanotubes [71]; (b) Schematic diagram of metal porphyrins and PDDA co-assembled into multi-level supramolecular nanostructures [72].

Figure 5

(a) Nucleation and growth of porphyrin nanostructures; (b) SEM image of CTAB-THPP nanowires; (c) SEM image of CTAB-THPP nanorods [74]; (d) SEM image of CTAB-TCPP aggregates; (e) SEM image of TCPP powder; (f) SEM image of TCPP aggregates [75].

Figure 6

(a) Schematic diagram of the co-assembly of TPPS catalyst and dipeptide (KK) into fiber bundles and photocatalysis [76]; (b) Schematic design and construction of light capture antenna (Co-I₄K₂/TPPS/Pt complex) [36].

Figure 7

(a) Schematic diagram of a supramolecular membrane photocatalytic system based on HBVP hybrid vesicles [80]; (b) Dendritic macromolecule-porphyrin self-assembly and photocatalytic reduction in methyl violet (MV) [81].

Figure 8

(a) Schematic diagram of the design and construction of a light-harvesting antenna based on the absence of precious metal porphyrins [82]; (b) ZnTCPP self-assembly diagram via π-π interactions; (c) SA-ZnTCPP SEM diagram; (d) SA-ZnTCPP TEM diagram [83].

Figure 9

(a) Schematic diagram of three different types of heterojunction electron-hole pair separation [93]; (b) Photocatalytic charge transfer mechanism of S-TCPP/ZnFe-LDH heterojunction [94].

Figure 10

(a) Z-type heterojunction electrons-Schematic diagram of hole pair separation [97]; (b) Photocatalytic charge transfer mechanism of T-TP/PDI heterojunction [98]; (c) Photocatalytic mechanism of TC degradation on TCP/G/BMO under visible light irradiation [99].

Figure 12

(a) Schematic diagram of the photocatalytic mechanism of co-assembly supramolecular TPPS/PDI [109]; (b) Chemical structures of ligands NDI and H₂DPBP; (c) Schematic diagram of the mechanism of Zr-NDI-H₂DPBP-MOF photocatalytic amine coupling reaction [111].

Figure 13

(a) Synthetic routes of TCyPPP, TbePPP, and TPyPPP; (b) Stability test of self-assembled photocatalytic activity of TCyPPP [129]; (c) Schematic diagram of the synthesis of self-assembled ZnTPyP nanoparticles and ZnTPyP@NO nanoparticles [130]; (d) Photocatalytic cycle of SA-PtPFTPP; (e) Photocatalytic cycle of SA-PtTPP [131].

Figure 14

(a) Schematic structures of PFC-71, PFC-72-Co, and PFC-73-Ni/Cu/Zn; (b) N₂ adsorption isotherm (77 K) of PFC-71 after different treatments; (c) N₂ adsorption isotherm of PFC-72 after different treatments; (d) N₂ adsorption isotherm of PFC-73 after different treatments [136].

Figure 15

(a) Schematic diagram of the formation of self-assembled InTPP nanostructures by an emulsion-based self-assembly process; (b) Photocatalytic recovery experiments of InTPP [137]; (c) Photocatalytic rates of different photocatalysts at 5 h; (d) Hydrogen production plots over different photocatalysts under light irradiation [138].

Figure 17

(a) Photoreduction mechanism of ZnTP/CN photocatalyst under illumination; (b) Natural gas product generation rates for ZnTP, CN, and ZnTP/CN [157]; (c) TCPP-C₃N₄ reaction mechanism diagram; (d) Visible light-driven CO₂ photoreduction performance [159].

Figure 18

(a) Schematic diagram of energy levels and electron transfer in a biomimetic artificial photosynthesis system; (b) Time curves for photocatalytic regeneration of NADH by NAD with different supramolecular assemblies [169].