# Improved Hummers method with K₂FeO₄

> A NaNO₃-free variant of the Hummers method in which potassium ferrate (K₂FeO₄) takes over part of the oxidizing work of KMnO₄. Graphite is intercalated and oxidized in sulfuric acid in two stages, then diluted with hot water to give graphene oxide.

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- Updated: 2026-10-14
- Category: Graphene synthesis
- Method: Hummers method, top-down
- Starting materials: Natural graphite flakes (10 g)
- Product: Graphene oxide (GO) sheets with epoxide, hydroxyl and carboxyl groups
- Typical size: nm–µm sheets (lateral size depends on the graphite)
- Key result: Highly oxidized GO; insulating until reduced
- Scalability: High: batch wet chemistry
- Figure: 1920 × 1080 px, 59 editable layers (15 generated objects with settings)

## Steps

1. **I · Intercalation and first oxidation**: K₂FeO₄ and KMnO₄ in 100 mL H₂SO₄, 0–5 °C, 1.5 h
2. **II · Deep oxidation**: A second oxidant feed, 35 °C, 3 h
3. **III · Dilution and exfoliation**: 250 mL H₂O, 95 °C, 30 min

## Strengths

- No NaNO₃, so no toxic NOₓ fumes
- Less KMnO₄ than the classic recipe
- Three steps in one vessel

## Limitations

- Strong oxidants and concentrated acid: exothermic, needs cooling
- GO is defective and insulating until reduced
- Acid and metal-salt waste to treat

## Uses

- Precursor to reduced graphene oxide
- Membranes and coatings
- Composites and printed electrodes

## References

1. Yu et al., “High-efficient synthesis of graphene oxide based on improved Hummers method”, Sci. Rep. 2016. https://doi.org/10.1038/srep36143 (primary)
2. Hummers & Offeman, “Preparation of graphitic oxide”, J. Am. Chem. Soc. 1958. https://doi.org/10.1021/ja01539a017 (method origin)
3. Marcano et al., “Improved synthesis of graphene oxide”, ACS Nano 2010. https://doi.org/10.1021/nn1006368 (further reading)

Credit: Redrawn and simplified after Yu et al., Sci. Rep. 2016 (doi:10.1038/srep36143).

## Questions

**What does the “Improved Hummers method with K₂FeO₄” template show?** A NaNO₃-free variant of the Hummers method in which potassium ferrate (K₂FeO₄) takes over part of the oxidizing work of KMnO₄. Graphite is intercalated and oxidized in sulfuric acid in two stages, then diluted with hot water to give graphene oxide.

**What are the steps shown in “Improved Hummers method with K₂FeO₄”?** 1. I · Intercalation and first oxidation: K₂FeO₄ and KMnO₄ in 100 mL H₂SO₄, 0–5 °C, 1.5 h. 2. II · Deep oxidation: A second oxidant feed, 35 °C, 3 h. 3. III · Dilution and exfoliation: 250 mL H₂O, 95 °C, 30 min.

**What are the starting materials and the product?** Starting materials: Natural graphite flakes (10 g). Product: Graphene oxide (GO) sheets with epoxide, hydroxyl and carboxyl groups.

**Which papers is “Improved Hummers method with K₂FeO₄” based on?** Yu et al., “High-efficient synthesis of graphene oxide based on improved Hummers method”, Sci. Rep. 2016 (doi:10.1038/srep36143); Hummers & Offeman, “Preparation of graphitic oxide”, J. Am. Chem. Soc. 1958 (doi:10.1021/ja01539a017); Marcano et al., “Improved synthesis of graphene oxide”, ACS Nano 2010 (doi:10.1021/nn1006368).

**Can I edit the “Improved Hummers method with K₂FeO₄” template?** Yes. Open it in the LabCanvas editor: all 59 layers are editable, including 15 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).