# What is the difference between graphite oxide and graphene oxide?

I am considering making a sheet of graphene using the LightScribe technique and I have read that I need graphite oxide. However when I look up graphite oxide for sale, graphene oxide pops up.

Are these two oxides similar? What is the difference?

• And while I am at it, what is the difference between CO2 and graphite/graphene oxide? – Pegan Apr 4 '13 at 17:53
• I love your answer. I got the terms mixed up and have been searching for hours myself. I believe the term graphene/graphene oxide/graphite oxide/graphene nanoplatelets should all be defined clearer. Not a big fan of companies selling graphene nanoplatelets at USD 160 per gram as their products often do not have the properties of graphene. Anything over should not be sold as a product with a graphene it its name. – user4347 Jan 29 '14 at 8:13

In short, graphite is several graphene sheets piled one above another.

Graphene is made up of one single sheet of carbon atoms arranged in hexagonal pattern (like a honeycomb), and graphite are several such sheets, each sheet linked to another by weak intermolecular forces, which gives the graphite its lubricative properties.

EDIT: Similarly, graphene oxide is a layer of graphene with oxygen atoms, $OH$ groups and $COOH$ groups attached to it, while graphite oxide are layers of graphene oxide.

Because of the presence of $COOH$ groups, graphite oxide can disperse in basic solutions (or even water!) to give graphene oxide.

$CO_2$ is simply carbon dioxide, one carbon atom doubly bonded two two oxygen atoms.

By contrast, graphite oxide is like a huge field of carbon with the groups I mentioned earlier while carbon dioxide is like a small ball.

• I need Graphite Oxide too, should I buy Graphene Oxide? I understand the difference but I'm a bit confused! – Alpha Mineron Oct 12 '17 at 15:27

I'm hardly an authority on graphene structures (only been reading the literature for about a year), but let me try to contribute.

Unfortunately it seems that research into graphene and its derivatives is progressing at such a pace that it can be hard to standardize notation. I have actually previously had a small discussion on the internet regarding the difference between graphene oxide and graphite oxide.

First, let's talk about graphene itself (for the sake of completeness). Originally the term meant a honeycomb sheet with single atom thickness, however it seems to have slightly evolved in usage to mean "graphite thin enough to show peculiar properties". According to Geim and Novoselov (The rise of graphene, 2007), there is a distinction to be made between single-layer graphene, bilayer graphene and few-layer graphene (3-10 layers) based on their electronic structure. Anything above 10 sheets thick already is electronically sufficiently similar to bulk graphite that it can be called as such. However, there also seems to be another term on the rise for stacks over 10 layers thick, with a still small but not well-defined upper limit, called graphite nanoplatelets (or confusingly, graphene nanoplatelets, depending on who you ask).

Regarding graphene/graphite oxide, I follow the interpretation suggested by Ruoff's group (2011). As far as I understand, when dry or dissolved in a highly concentrated, non-basic solution with little stirring, the individual oxidized sheets tend to stay stacked, and one may speak of graph*ite* oxide. If the oxidized sheets are in a basic, dilute, and/or vigorously stirred or sonicated solution, or if the sheets are supported on a substrate and proven to be composed of few layers, then they are unstacked (exfoliated) and one can speak of graph*ene* oxide. Theoretically, there is no composition difference between graphite and graphene oxide, since it's merely a matter of aggregation (The chemistry of graphene oxide, 2010). The difference would be like that between bulk gold and colloidal gold; the composition is the same, but they are chemically different. I have been informed that it is also common to refer to the stacked oxidized sheets as graphene oxide, and that separate sheets are called exfoliated graphene oxide. I don't agree very much with that standard, though, since it doesn't make too much sense to me.

To make things increasingly complicated, it seems that what most people considered to be graphene/graphite oxide is actually neither, but a mixture of oxidized graphitic sheets with highly oxidized polycyclic molecules, collectively called tannic acids or oxidized debris, given they appear as side-products during the process of vigorous oxidation of graphite (Rourke et al., 2011). These debris can make up as much as 30% of the dry weight of graphite oxide prepared via Hummers and Offeman graphite oxidation, and they have also been reported as side products of the oxidation of CNTs with HNO$_{3}$. It could well be that many properties previously attributed to graphene/graphite oxide are in fact strongly altered by the presence of these debris, which stay adsorbed to the graphene sheets via $\pi - \pi$ interactions and hydrogen bonding. For example, graphite oxide is only appreciably soluble in polar solvents such as water, DMSO and NMP because the debris act as a surfactant of sorts, stabilizing the suspension. When removed, the purified graphene oxide sheets are actually quite insoluble in most solvents, much like the non-oxidized sheets. Also, perhaps the existence of previously undetected debris is part of the reason why there are still debates on the proper model for the structure of graphene oxide.

In short, graphene and graphite oxide, while not exactly the same, are terms used interchangeably, and it's possible to go from one to the other reversibly by adding/removing solvent (as long as no concentrated base is added, or dilute base with heating). "Graphene" is a trendier term though, so that's usually what oxidized graphite will be advertised as. Though in actuality, due to the presence of debris, without purification it is really neither!

Edit: Ever since I wrote this answer, it seems that efforts to begin standardizing the nomenclature of graphene-related carbon nanostructures are underway (free access). Quoting from the article:

Graphene oxide (GO) – chemically modified graphene prepared by oxidation and exfoliation that is accompanied by extensive oxidative modification of the basal plane. Graphene oxide is a monolayer material with a high oxygen content, typically characterized by C/O atomic ratios less than 3.0 and typically closer to 2.0.

Graphite oxide – a bulk solid made by oxidation of graphite through processes that functionalize the basal planes and increase the interlayer spacing. Graphite oxide can be exfoliated in solution to form (monolayer) graphene oxide or partially exfoliated to form few-layer graphene oxide.

Note that the definitions proposed in the article will not necessarily take hold, and even if they do the transition will take some time. Be wary of nomenclature mismatches during this period.

Also, in my post I mention the presence of oxidized debris in graphite oxide. Research is still ongoing to determine their nature and properties.