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CN-121974957-A - Supermolecular layer photocatalytic material for pi-pi stacking regulation and control of synergistic CO2 reduction, and preparation method and application thereof

CN121974957ACN 121974957 ACN121974957 ACN 121974957ACN-121974957-A

Abstract

The invention relates to the technical field of photocatalytic materials, in particular to a supermolecular layer photocatalytic material for pi-pi stacking regulation and synergy CO2 reduction, a preparation method and application thereof, wherein the molecular formula of a single crystal structure of the photocatalytic material is Fe (L 1 ) 4 (SCN) 2 or Fe (L 2 ) 2 (SCN) 4 ; wherein L 1 is 1,1 '-methylenebis [ 1H-benzimidazole ]; L 2 is 1,1' -methylenebis [ 2-methyl-1H-imidazole ]; and provides two iron-based pi adhesion supermolecular layered photocatalytic materials based on a mononuclear complex.

Inventors

  • ZHU ZIHAN
  • ZHANG JING
  • Xu Ruxue
  • WU JING
  • SUN HAO
  • WU DAYU
  • HUANG WEI

Assignees

  • 常州大学

Dates

Publication Date
20260505
Application Date
20260128

Claims (10)

  1. 1. A pi-pi stacking control synergistic CO 2 reduced supermolecular layer photocatalytic material is characterized in that the single crystal structure molecular formula of the photocatalytic material is Fe (L 1 ) 4 (SCN) 2 or Fe (L 2 ) 2 (SCN) 4 ; wherein L 1 is 1,1 '-methylenebis [ 1H-benzimidazole ]; L 2 is 1,1' -methylenebis [ 2-methyl-1H-imidazole ].
  2. 2. The pi-pi stacking control synergistic CO 2 reduced supramolecular layered photocatalytic material of claim 1, wherein the unit cell of Fe (L 1 ) 4 (SCN) 2 ) comprises two independent iron atoms, each iron atom being coordinated with two SCN - ions and four L 1 ligands, each iron atom being coordinated with four imidazole nitrogen atoms in four L 1 ligands and two nitrogen atoms in two thiocyanate ions in a six-coordinated octahedral geometry, wherein each L 1 ligand acts as a bidentate ligand, bonding with an iron atom through its nitrogen atoms on two benzimidazole rings, and the unit cell parameters are a= 26.1105 (5) a, b= 26.8714 (5) a, c= 31.2040 (6) a, a=90 °, β=90 °, γ=90 °, z= 8,V = 21893.5 (7) a 3 .
  3. 3. The pi-pi stacking control synergistic CO 2 -reduced supramolecular layer photocatalytic material according to claim 1, wherein the asymmetric unit of Fe (L 2 ) 2 (SCN) 4 ) contains one iron atom coordinated with two independent L 2 ligands and four SCN - ions in a coordination mode in which each iron atom is coordinated with two imidazole nitrogen atoms in two L 2 ligands and four nitrogen atoms in four thiocyanate ions to form a hexacoordinated octahedral geometry in which each L 2 ligand acts as a bidentate ligand, through which nitrogen atoms on two methylimidazole rings are bonded to the iron atoms, and the unit cell parameters are a= 10.7035 (7) a, b= 16.9391 (9) a, c= 16.3797 (15) a, α=90 °, β= 107.340 (7) °, γ=90 °, z=4, v= 2834.8 (4) a 3 .
  4. 4. The pi.pi.pi.stacking control synergistic CO 2 reduced supramolecular layer photocatalytic material according to claim 1, wherein the Fe (L 1 ) 4 (SCN) 2 mononuclear structural units form a two-dimensional network structure only through pi.pi interaction, the Fe (L 2 ) 2 (SCN) 4 mononuclear structural unit and C ‒ H. Pi. Interact through pi. Interaction to form a two-dimensional network structure.
  5. 5. The method for preparing the pi-pi stacking control synergistic CO 2 reduced supermolecular layer photocatalytic material according to any one of claims 1-4, the method for preparing the Fe (L 1 ) 4 (SCN) 2 is characterized in that: S1, mixing benzimidazole and potassium hydroxide in DMSO, stirring at room temperature, then adding dibromomethane, continuing stirring, adding water for dilution after the reaction is finished, extracting with dichloromethane, drying an organic phase by anhydrous magnesium sulfate, and distilling under reduced pressure to obtain L 1 ; S2, adding the L 1 and potassium thiocyanate into a methanol solution, uniformly mixing to obtain a mixed solution, then placing the mixed solution, a ferrous chloride aqueous solution and the methanol aqueous solution into a reaction container according to the order of the density from high to low, sealing and standing to obtain Fe (L 1 ) 4 (SCN) 2 ).
  6. 6. The method for preparing the supermolecular layer photocatalytic material by pi.pi.stacking control synergistic CO 2 reduction according to claim 5, wherein the molar ratio of benzimidazole to potassium hydroxide in the step S1 is 1:2-5; the volume ratio of DMSO to dibromomethane to water to dichloromethane is 7-13:1:140-160:20-40.
  7. 7. The preparation method of the pi-pi stacking control synergistic CO 2 reduced supermolecular layer photocatalytic material according to claim 5, wherein in the step S2, the molar ratio of L 1 to potassium thiocyanate to ferrous chloride is 3-5:1.5-2.5:1, and the volume ratio of the mixed solution to aqueous methanol solution to ferrous chloride solution is 1.5-3:1-2:1.5-3.
  8. 8. The method for preparing the pi-pi stacking control synergistic CO 2 reduced supermolecular layer photocatalytic material according to any one of claims 1-4, the method for preparing the Fe (L 2 ) 2 (SCN) 4 is characterized in that: A1, stirring 2-methylimidazole, sodium hydroxide and tetraethylammonium bromide in a mixed solvent of water and methylene dichloride, heating and refluxing, extracting with methylene dichloride after the reaction is finished, washing with water, drying an organic phase by anhydrous magnesium sulfate, and distilling under reduced pressure to obtain L 2 ; a2, adding L 2 and potassium thiocyanate into a container filled with acetonitrile, stirring and dissolving, slowly adding ferrous chloride, continuously stirring and mixing uniformly, filtering, standing and slowly evaporating to obtain reddish brown crystals, namely Fe (L 2 ) 2 (SCN) 4 ).
  9. 9. The preparation method of the pi-pi stacking control synergistic CO 2 reduced supermolecular layer photocatalytic material according to claim 8, wherein in the step A1, the molar ratio of 2-methylimidazole to sodium hydroxide to tetraethylammonium bromide is 1:6-7:0.02-0.04, and the volume ratio of water as a solvent, dichloromethane as an extractant and water for washing is 3-6:17-23:25-35:4-8.
  10. 10. The application method of the supermolecular layer photocatalytic material for pi-pi stacking control synergistic CO 2 reduction according to any one of claims 1-4, characterized in that the photocatalytic material is used as a catalyst in the field of preparing CO by photocatalysis.

Description

Supermolecular layer photocatalytic material for pi-pi stacking regulation and control of synergistic CO2 reduction, and preparation method and application thereof Technical Field The invention relates to the technical field of photocatalytic materials, in particular to a supermolecular layer photocatalytic material for pi-pi stacking regulation and synergy CO 2 reduction, and a preparation method and application thereof. Background With the acceleration of the global industrialization process, excessive consumption of fossil fuels causes continuous rise of carbon dioxide concentration in the atmosphere, which causes a series of global problems. The photocatalytic CO 2 reduction technology, which directly converts greenhouse gas CO 2 into high-added-value fuels (such as carbon monoxide, methane, methanol and the like) or chemical raw materials by using solar energy, is considered to be an ideal strategy capable of simultaneously solving the energy and environmental problems. Unfortunately, despite the broad prospects, the trend of efficient catalytic materials for photoreduction of CO 2 from laboratory to practical applications still faces serious challenges such as (1) low light capturing capability, (2) difficulty in photogenerated carrier separation and migration, and (3) slow surface reaction kinetics. The supermolecule complex and the two-dimensional supermolecule layer thereof form an adjustable structure through non-covalent action, and have three advantages in photocatalysis, namely, the supermolecule complex can accurately adjust and control the pore channel structure to realize selective identification of reactants, can construct a high-efficiency electron transfer channel to improve charge separation efficiency, and the cavity structure can realize host-guest synergistic catalysis and multi-step serial reaction. The characteristics lead the application prospect in the fields of photocatalytic energy and environment to be wide. The framework material based on pi-pi stacking interaction is widely focused in the field of photocatalysis, the pi-pi stacking interaction is derived from strong dispersion force and dipole action among aromatic rings, the crystal structure and electronic performance of the material can be regulated, an efficient charge transmission channel can be constructed, and the light absorption and exciton generation capacity of the material can be effectively enhanced by selecting a proper conjugated aromatic ligand. However, the inherent weakness of pi.pi.pi.stacking interactions results in a general lack of framework stability, which severely restricts practical applications, especially in the field of CO 2 photoreduction, and it has been recently reported that pi.pi.pi.stacking frameworks based on metal complexes can achieve both high catalytic efficiency and good stability. Therefore, how to precisely regulate pi.pi.stacking modes at the molecular level, and balance material stability and electron transport properties has become a key challenge for the development of the field. The information disclosed in this background section is only for enhancement of understanding of the general background of the disclosure and is not to be taken as an admission or any form of suggestion that this information forms the prior art that is well known to a person skilled in the art. Disclosure of Invention The invention provides a pi-pi stacking control synergistic CO 2 reduced supermolecular layer photocatalytic material, a preparation method and application thereof, and provides two iron-based pi-adhesion supermolecular layered photocatalytic materials based on mononuclear complexes, wherein pi-pi interaction is accurately controlled through ligand rational design to form a two-dimensional structure, excellent catalytic activity is shown in the reaction of preparing CO by CO 2 photocatalytic reduction, and the key effect of pi-pi stacking as a high-efficiency electron transmission channel in improving photocatalytic efficiency is highlighted. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The first aspect of the invention provides a supermolecular layer photocatalytic material for pi.pi.stacking control synergistic CO 2 reduction, wherein the single crystal structure molecular formula of the photocatalytic material is Fe (L 1)4(SCN)2 or Fe (L 2)2(SCN)4; wherein L 1 is 1,1 '-methylenebis [ 1H-benzimidazole ]; L 2 is 1,1' -methylenebis [ 2-methyl-1H-imidazole ]; fe (L 1)4(SCN)2 is denoted as complex 1, and Fe (L 2)2(SCN)4 is denoted as complex 2). Preferably, the unit cell of Fe (L 1)4(SCN)2) comprises two independent iron atoms, each iron atom is coordinated with two SCN - ions and four L 1 ligands, the coordination mode is that each iron atom is coordinated with four imidazole nitrogen atoms in four L 1 ligands and two nitrogen atoms in two thiocyanate ions to form a hexacoordinated octahedral geometry, wherein each L 1 ligand is used as