Polymer Photocatalysts
Published: 2023-12-12 07:52:39

Classification
Carbon nitrides is a type of triazine or heptazine-based polymer containing carbon and nitrogen, commonly referred to as graphitic carbonitride (g-C3N4), which is a layered crystal structure based on heptazine. Carbon nitride is an effective substitute for graphite and amorphous carbon in various fields such as catalyst supports.
Conjugated polymers (CPs) are promising alternatives to conventional inorganic semiconductor photocatalysis, with unique advantages such as low cost, high chemical stability, and molecularly tunable optoelectronic properties.
Covalent triazine frameworks (CTFs) represent the bridge between carbon nitride materials and conjugated organic polymers, combining the thermal stability and strong triazine motif of PTI-type carbon nitrides with variable rigidity arenes.
Covalent organic frameworks (COFs) are a new class of 2D or 3D crystalline polymers formed by linking organic building blocks into extended structures. The high crystallinity facilitates charge separation and transport, making COFs with good catalytic activity.
Applications
Organic [polymer photocatalysts](https://www.alfachemic.com/catalysts/products/polymer-photocatalysts.html) usually contain π-conjugated structures, which makes them have many interesting properties that differentiate them from inorganic semiconductors in the field of photocatalysis. Organic polymer photocatalysts have been widely studied and applied in photocatalytic water splitting, CO2 photocatalytic reduction, light-driven organic transformation, and photocatalytic degradation of organic dyes.

Photocatalytic water splitting
Photocatalytic water splitting technology provides an efficient way to utilize the abundant water and sunlight in nature to produce clean hydrogen production. So far, a series of conjugated polymers have been well designed for photocatalytic hydrogen evolution from water under illumination. The photocatalytic activity of the as-prepared polymers varies with the different structures, compositions, and optical properties of the polymer chains.

Photocatalytic CO2 reduction
Using sunlight to reduce CO2 through H2O is an innovative approach to addressing the growing environmental challenges.

Photocatalytic organic conversion
Generally, photocatalytic organic transformations are initiated by exciting polymeric photocatalysts to generate electrons and holes, which react with organic substrates to form radical intermediates. These reactive intermediates are further converted to final products by rearrangements or reactions with other species on the surface or in bulk solution.

Photocatalytic degradation of organic dyes
Photocatalytic degradation of organic dyes into less harmful compounds offers an attractive approach for environmental remediation. For example, the linear conjugated polymers with unique nanostructures showed great promise for the degradation of organic dyes. The soft-template method was used to prepare nanofibers of poly(diphenylbutadiyne) by photopolymerization that could decompose methyl orange in water.

References
Chunhui Dai. (2019). "Conjugated polymers for visible-light-driven photocatalysis," Energy & Environmental Science 13: 24-52.
Can Yang. (2018). "Functional Conjugated Polymers for CO2 Reduction Using Visible Light," Chemistry - A European Journal 24(66): 17454-17458.
Srabanti Ghosh. (2015). "Conducting polymer nanostructures for photocatalysis under visible light," Nature Materials 14: 505-511.