Carbon Nitride Photocatalyst Supramolecular Assembly
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Solution Overview
Problem
Current photocatalysts, such as titanium dioxide, have limited photocatalytic activity due to wide bandgaps, restricting their ability to absorb visible light and requiring costly post-separation processes, and existing carbon nitrides suffer from low surface area and rapid electron-hole pair recombination.
Innovation Solution
A novel supramolecular self-assembly with a high N—C═N bond ratio is formed through hydrogen bonding of nitrogen-containing compounds, which is then polycondensed and heat-treated to create a carbon nitride with a heptazine framework, combined with a metal oxide to enhance photocatalytic activity under visible light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If titanium dioxide is used as a photocatalyst, then high photocatalytic activity and stability are achieved, but limited visible light absorption occurs due to wide bandgap
Solution Approach 1:
The patent employs composite materials by combining carbon nitride with metal oxides (such as TiO2, ZnO, or Fe2O3) to create a heterojunction structure. This composite approach allows the material to maintain the stability of metal oxides while gaining the visible light absorption capability of carbon nitride, effectively resolving the contradiction between stability and visible light utilization.
Solution Approach 2:
The patent modifies the bandgap parameter of the photocatalyst by introducing carbon nitride into the metal oxide structure. This changes the energy band structure, reducing the bandgap from the typical 3.0-3.2 eV of pure TiO2 to a narrower range that enables visible light absorption, while maintaining structural stability through the composite architecture.
2Reliability
If titanium dioxide particles are suspended in liquid phase, then photocatalytic activity is achieved, but post-separation becomes difficult due to fine particles in slurry state
Solution Approach 1:
The patent utilizes the formation of thin film structures or aggregated particle structures where carbon nitride coats or aggregates with metal oxide particles. This creates a structured morphology that maintains high surface area for catalysis while enabling easier separation through filtration or sedimentation compared to fine suspended particles.
3Use of energy by moving object
If existing carbon nitride is used, then visible light absorption is improved, but low surface area and rapid electron-hole pair recombination occur
Solution Approach 1:
The patent segments the carbon nitride structure into smaller domains or layers combined with metal oxide particles, creating a hierarchical structure. This segmentation increases the effective surface area while maintaining the visible light absorption properties of carbon nitride, and the segmented structure also provides more interfaces for charge separation, reducing recombination.
4Use of energy by moving object
If existing carbon nitride is used, then visible light absorption is improved, but rapid electron-hole pair recombination reduces photocatalytic efficiency
Solution Approach 1:
The patent introduces metal oxide particles as intermediary structures between light absorption and charge separation. The metal oxide acts as a mediator that facilitates charge separation by providing alternative electron transfer pathways, reducing the direct recombination of electron-hole pairs in carbon nitride while preserving visible light absorption capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The resulting photocatalyst exhibits improved photocatalytic activity, broader light absorption, and increased oxidation/reduction reactivity, effectively degrading organic contaminants like rhodamine B and tetracycline with enhanced charge separation and mobility.
Implementation Method 1
a supramolecular self-assembly which includes a plurality of complex units formed by hydrogen bonding of two or more nitrogen-containing compounds to each other; and a linker unit configured to connect the plurality of complex units via a hydrogen bond
Implementation Method 2
When a photocatalyst absorbs photons with energy exceeding the bandgap, excited electrons may be obtained from a valence band to a conduction band, and electron holes are formed by the excited electrons
Implementation Method 3
The excited electrons are captured by O2 and H2O molecules, thereby generating the above-described radicals. The generated radicals degrade organic contaminants through a series of oxidation/reduction reactions
Implementation Method 4
A novel supramolecular self-assembly with a high N—C═N bond ratio is formed through hydrogen bonding of nitrogen-containing compounds, which is then polycondensed and heat-treated to create a carbon nitride with a heptazine framework
Implementation Method 5
which is then polycondensed and heat-treated to create a carbon nitride with a heptazine framework
Data Source
AI summary
The present invention relates to a novel supramolecular self-assembly, a carbon nitride and a photocatalyst using same, and a manufacturing method therefor. The present invention can provide, by using a supramolecular self-assembly, a carbon nitride having a high N—C═N bonding ratio, a photocatalyst having excellent photocatalytic activity under visible light, and a manufacturing method therefor, the supramolecular self-assembly comprising: a plurality of complex units formed by hydrogen bonding two or more nitrogen-containing compounds to each other; and linker units connecting the plurality of complex units by hydrogen bonds, wherein the nitrogen-containing compounds and the linker units are each independently a —NH group and capable of hydrogen bonding with the —NH group, and the supramolecular self-assembly contains one or more heteroatoms selected from the group consisting of N, S, and O.