One of the most persistent sources of confusion in the graphene industry is the assumption that “graphene,” “graphene oxide,” and “reduced graphene oxide” are variations of the same thing. They are not. These are three materially different substances with different atomic structures, different electrical and mechanical behavior, different manufacturing routes, and different price points. Treating them as interchangeable — or worse, buying one when your application requires another — is one of the most common and most expensive mistakes in graphene procurement.
This article explains what each material actually is, how they differ at the atomic level, and why those differences matter for real-world applications.
Graphene: The Pristine Carbon Sheet
Graphene in its ideal form is a single layer of carbon atoms arranged in a hexagonal (honeycomb) lattice. Every carbon atom forms three strong in-plane bonds (called sp² bonds) with its neighbors and contributes one electron to a delocalized system above and below the plane. This structure gives graphene its extraordinary combination of properties: exceptional electrical conductivity, mechanical strength exceeding 100 times that of steel when normalized by weight, optical transparency of about 97.7% per layer, and thermal conductivity among the highest of any known material.
The key word here is pristine. These headline properties — the ones that earned Geim and Novoselov the 2010 Nobel Prize in Physics — describe defect-free, single-layer graphene with clean interfaces. In practice, achieving this quality at scale is difficult and expensive. Most commercially available “graphene” is produced by chemical vapor deposition (CVD) on copper foil for film applications, or by liquid-phase exfoliation for bulk powders. Both processes introduce some level of defects, contamination, or multi-layer content.
What makes graphene graphene: an intact sp² carbon network with no (or very few) oxygen groups, holes, or chemical modifications. It is electrically conductive, mechanically strong, chemically stable, and hydrophobic (it repels water).
Graphene Oxide: The Chemically Modified Version
Graphene oxide (GO) is produced by aggressively oxidizing graphite — typically using variations of the Hummers method, which employs strong acids and powerful oxidants like potassium permanganate. This process forces oxygen-containing functional groups (hydroxyl, epoxy, carboxyl, and carbonyl groups) onto the carbon lattice. The result is a material that looks structurally similar to graphene on a transmission electron microscope image but behaves completely differently.
The oxygen groups do two important things. First, they disrupt the continuous sp² bonding network that gives graphene its conductivity. Large regions of the carbon lattice are converted to sp³ bonding (the same type found in diamond), creating an electrically insulating material. GO’s sheet resistance can exceed 10¹² Ω/sq — effectively making it an insulator. Second, the oxygen groups make GO strongly hydrophilic: it disperses readily in water, which is both its greatest practical advantage and the reason it exists as a commercial product.
This water-dispersibility is why GO has become one of the most commercially available “graphene-related” materials. It can be processed using standard chemical batch equipment, dispersed without exotic solvents, and coated, printed, or cast from aqueous solutions. A 2024 review on mass production of GO noted that interest in GO has grown partly because pristine graphene production routes remain challenging to industrialize, making GO a more accessible intermediate.
However, GO comes with significant quality challenges. A 2023 study that characterized 34 commercially available GO products found wide variation in properties — oxygen content, layer count, lateral size, and defect levels differed substantially between suppliers and even between batches from the same supplier. The study explicitly framed this lack of standardization as a trust barrier in the market.
What makes GO different from graphene: heavy oxygen functionalization that destroys electrical conductivity but enables water dispersibility. GO is an insulator, not a conductor. It is hydrophilic, not hydrophobic. Its carbon lattice is substantially damaged.
Reduced Graphene Oxide: The Attempted Restoration
Reduced graphene oxide (rGO) is what you get when you try to undo the oxidation damage and restore GO back toward pristine graphene. Reduction can be achieved through chemical methods (using reducing agents like hydrazine or ascorbic acid), thermal methods (heating to high temperatures to drive off oxygen groups), or other approaches including electrochemical and photochemical reduction.
The reduction process partially restores the sp² carbon network, reconnecting conductive pathways and significantly improving electrical conductivity compared to GO. But — and this is the critical point — rGO never fully returns to pristine graphene. The oxidation process creates permanent structural damage: vacancies (missing carbon atoms), holes in the lattice, and residual oxygen groups that resist removal. Think of it like crumpling a sheet of paper and then trying to flatten it — you can get it mostly flat, but the crease marks remain.
The electrical improvement can be dramatic in relative terms. GO starts as an insulator; rGO can achieve conductivity several orders of magnitude higher. But in absolute terms, rGO is still significantly more resistive than high-quality CVD or mechanically exfoliated graphene. The residual defects scatter electrons and limit carrier mobility.
An interesting subtlety: Raman spectroscopy — the standard tool for assessing graphene quality — can be misleading when applied to rGO. The D-band intensity (which indicates disorder) can actually increase after reduction, even though the material is becoming more conductive. This happens because reduction can create smaller but more numerous graphitic domains, increasing the number of domain edges that contribute to the D-band signal. Interpreting rGO Raman spectra requires care and context that single-point measurements cannot provide.
What makes rGO different from both: partially restored conductivity, but with permanent structural defects. Better than GO electrically, but inferior to pristine graphene. Still more processable than CVD graphene for many bulk applications.
Side-by-Side Comparison
| Property | Graphene (pristine) | Graphene Oxide (GO) | Reduced Graphene Oxide (rGO) |
|---|---|---|---|
| Carbon bonding | Predominantly sp² | Mixed sp²/sp³ (heavy sp³) | Mostly sp² (restored), some residual sp³ |
| Oxygen content | Minimal to none | High (C:O ratio often 2:1 to 4:1) | Reduced but not eliminated (C:O often 8:1 to 12:1) |
| Electrical conductivity | Excellent (sheet resistance often hundreds of Ω/sq for CVD films) | Insulating (sheet resistance can exceed 10¹² Ω/sq) | Moderate (orders of magnitude better than GO, still below pristine graphene) |
| Water dispersibility | Hydrophobic — does not disperse in water | Excellent — disperses readily in water | Reduced hydrophilicity; may require surfactants |
| Structural integrity | Intact lattice (defects depend on production method) | Heavily disrupted; vacancies, holes, functional groups | Partially restored; permanent damage from oxidation |
| Primary production route | CVD on copper, mechanical exfoliation, or liquid-phase exfoliation | Hummers-type oxidation of graphite | Chemical, thermal, or electrochemical reduction of GO |
| Scalability | CVD: moderate (area-limited). LPE: high (mass) | High (chemical batch processing) | High (follows GO production) |
| Typical cost | CVD films: $29,000–$200,000/m². Powders (FLG): $5–$17,000/kg depending on grade and scale | ~$1,000/kg at bulk scale; higher for controlled-quality grades | Similar to GO plus reduction processing costs |
| Key applications | Electronic devices, sensors, transparent conductors | Membranes, coatings, composites, biomedical (as precursor to rGO) | Conductive inks, energy storage electrodes, composites, coatings |
Why This Distinction Matters Commercially
The practical consequence of conflating these three materials is procurement failure. Here are the scenarios we see most often:
Buying GO when you need conductivity. If your application depends on electrical performance — sensors, conductive coatings, electrodes — GO will not work. Its sheet resistance is literally trillions of ohms per square. Yet GO is frequently marketed simply as “graphene” because it is cheaper and easier to produce. A 2023 characterization study of commercial GO products explicitly identified this mislabeling as a structural market problem.
Buying pristine graphene when you need processability. If you need a material that disperses in water for coating, membrane, or biomedical applications, pristine graphene’s hydrophobic nature works against you. GO’s oxygen groups are not a defect in this context — they are the feature. Paying premium prices for CVD graphene and then struggling to get it into aqueous suspension is a waste of money and time.
Assuming rGO is “good enough” as a graphene substitute. For some applications — energy storage additives, certain composites, conductive inks — rGO can be excellent. But for applications requiring high carrier mobility or pristine lattice properties (Hall sensors, RF electronics, precision metrology), rGO’s residual defects are disqualifying. The application mechanism determines which material you need.
The right approach is to start with your application’s dominant mechanism:
- Carrier transport (mobility, Hall effect, RF): you need pristine graphene, probably CVD monolayer
- Percolation/network conductivity (inks, composites, electrodes): rGO or few-layer graphene flakes can work
- Barrier/tortuosity (coatings, membranes): GO’s platelet structure and processability are often ideal
- Surface chemistry (functionalization, biomedical): GO’s oxygen groups are your starting point
The Mislabeling Problem
ISO and the Graphene Council have been working to create classification frameworks that distinguish graphene-related 2D materials by measurable attributes: layer number, lateral size, defect metrics, and oxygen content. These efforts exist precisely because the market has a persistent mislabeling problem. Products sold as “graphene” span the entire range from true monolayer material to multi-layer graphitic platelets to graphene oxide in disguise.
As a buyer, the most important thing you can do is request and verify the actual characterization data — not just the product name. Key metrics include: Raman spectroscopy statistics (not a single spectrum — ask for mapping data across multiple points), oxygen content or C:O ratio, layer count distribution from AFM or TEM, and lateral size distribution. Our Procurement Guide covers the full checklist.
The Bottom Line
Graphene, GO, and rGO are three points on a spectrum of carbon materials. They share a heritage in the graphite crystal structure, but their properties, processing, costs, and appropriate applications are fundamentally different. Understanding which one your application actually needs — and verifying that what you’re buying matches that need — is the single most important step in any graphene procurement decision.
This article is part of our Fundamentals series. For more on production methods, see How Graphene Is Made: Every Production Method Explained. For help specifying and sourcing graphene materials, see our Procurement Guide.