# g-C₃N₄ by thermal polymerization

> Melamine is heated in a covered crucible in a muffle furnace. It loses ammonia and condenses into graphitic carbon nitride, a yellow, layered polymer built from tri-s-triazine (heptazine) units linked by nitrogen. Heating the bulk powder again in air etches it into nanosheets about 2 nm thick with a much larger surface area, for visible-light photocatalysis.

- Page: https://www.labcanvas.com/templates/nanomaterial-synthesis/g-c3n4-thermal-polymerization-melamine
- Open in the LabCanvas editor (LabCanvas account): https://www.labcanvas.com/editor.html?template=gcn-thermal-polymerization
- Updated: 2026-10-14
- Category: Nanomaterial synthesis
- Method: Thermal polymerization, bottom-up
- Starting materials: Melamine (urea, cyanamide or dicyandiamide work too)
- Product: Bulk g-C₃N₄ powder, then g-C₃N₄ nanosheets
- Typical size: Bulk: micrometre particles of stacked layers; nanosheets about 2 nm thick (Niu et al.)
- Key result: Polymeric, partly condensed (some NH/NH₂ groups remain); crystallinity depends on precursor and temperature
- Scalability: Very high: cheap nitrogen-rich precursors, one heating step
- Figure: 1920 × 1080 px, 78 editable layers (16 generated objects with settings)

## Steps

1. **Precursor**: Melamine powder in a covered (alumina or porcelain) crucible
2. **Thermal polymerization**: Heated in a muffle furnace in air: deamination and condensation into tri-s-triazine units linked by N
3. **Bulk g-C₃N₄**: A yellow, layered solid; ground to a powder
4. **Thermal etching**: The bulk powder heated again at 500 °C in air is oxidized layer by layer into thin sheets (Niu et al.)
5. **Nanosheets**: About 2 nm thick, 306 m² g⁻¹ surface area (Niu et al.)

## Strengths

- Metal-free, cheap, made from abundant precursors
- Absorbs visible light
- Chemically and thermally stable

## Limitations

- Bulk material has a small surface area
- Fast recombination of charge carriers
- Exfoliation lowers the yield

## Uses

- Photocatalytic H₂ evolution from water
- Degradation of pollutants
- CO₂ reduction
- Sensing

## References

1. Yan, Li & Zou, “Photodegradation performance of g-C3N4 fabricated by directly heating melamine”, Langmuir 2009. https://doi.org/10.1021/la900923z (primary)
2. Wang et al., “A metal-free polymeric photocatalyst for hydrogen production from water under visible light”, Nat. Mater. 2009. https://doi.org/10.1038/nmat2317 (method origin)
3. Niu et al., “Graphene-like carbon nitride nanosheets for improved photocatalytic activities”, Adv. Funct. Mater. 2012. https://doi.org/10.1002/adfm.201200922 (primary)
4. Ong et al., “Graphitic carbon nitride (g-C3N4)-based photocatalysts for artificial photosynthesis and environmental remediation: are we a step closer to achieving sustainability?”, Chem. Rev. 2016. https://doi.org/10.1021/acs.chemrev.6b00075 (review)

Credit: Redrawn and simplified after Yan, Li & Zou, Langmuir 2009 (doi:10.1021/la900923z), Wang et al., Nat. Mater. 2009 (doi:10.1038/nmat2317) and Niu et al., Adv. Funct. Mater. 2012 (doi:10.1002/adfm.201200922); review: Ong et al., Chem. Rev. 2016 (doi:10.1021/acs.chemrev.6b00075).

## Questions

**What does the “g-C₃N₄ by thermal polymerization” template show?** Melamine is heated in a covered crucible in a muffle furnace. It loses ammonia and condenses into graphitic carbon nitride, a yellow, layered polymer built from tri-s-triazine (heptazine) units linked by nitrogen. Heating the bulk powder again in air etches it into nanosheets about 2 nm thick with a much larger surface area, for visible-light photocatalysis.

**What are the steps shown in “g-C₃N₄ by thermal polymerization”?** 1. Precursor: Melamine powder in a covered (alumina or porcelain) crucible. 2. Thermal polymerization: Heated in a muffle furnace in air: deamination and condensation into tri-s-triazine units linked by N. 3. Bulk g-C₃N₄: A yellow, layered solid; ground to a powder. 4. Thermal etching: The bulk powder heated again at 500 °C in air is oxidized layer by layer into thin sheets (Niu et al.). 5. Nanosheets: About 2 nm thick, 306 m² g⁻¹ surface area (Niu et al.).

**What are the starting materials and the product?** Starting materials: Melamine (urea, cyanamide or dicyandiamide work too). Product: Bulk g-C₃N₄ powder, then g-C₃N₄ nanosheets.

**Which papers is “g-C₃N₄ by thermal polymerization” based on?** Yan, Li & Zou, “Photodegradation performance of g-C3N4 fabricated by directly heating melamine”, Langmuir 2009 (doi:10.1021/la900923z); Wang et al., “A metal-free polymeric photocatalyst for hydrogen production from water under visible light”, Nat. Mater. 2009 (doi:10.1038/nmat2317); Niu et al., “Graphene-like carbon nitride nanosheets for improved photocatalytic activities”, Adv. Funct. Mater. 2012 (doi:10.1002/adfm.201200922); Ong et al., “Graphitic carbon nitride (g-C3N4)-based photocatalysts for artificial photosynthesis and environmental remediation: are we a step closer to achieving sustainability?”, Chem. Rev. 2016 (doi:10.1021/acs.chemrev.6b00075).

**Can I edit the “g-C₃N₄ by thermal polymerization” template?** Yes. Open it in the LabCanvas editor: all 78 layers are editable, including 16 generated objects (structures, plots, equipment) with their own settings. Change the text, colours and layout, then export PNG, TIFF, SVG or PDF.

**Do I need an account to use this template?** Not to view it here. To open and edit it, sign in to LabCanvas or create a free account (the free plan keeps one design of each kind). Downloading the figure is part of LabCanvas Pro (US$19 a month or US$199 a year).