Graphene oxide is– true to its name– oxidized graphene. ChemCeed’s article on graphene has already discussed a strange quirk in the history of graphene itself. Graphene was first discovered in 2004, even though carbon nanotubes (CNT), which are made of graphene, were discovered in 1991. Well, get ready for another surprising paradox: graphene oxide (GO) was first synthesized in 1859.
No, time travel wasn’t involved, and this seemingly impossible timeline has a perfectly logical explanation. It seems that in 1859, Oxford chemist Benjamin C. Brodie treated graphite (the substance that graphene is isolated from) with potassium chloride and nitric acid. The result was an oxidized form of graphite. But in that bubbling, fomenting substance, a true treasure was hidden: little bits of graphite that were flattened to the thickness of a single atom of carbon, bonded with oxygen. Such “two dimensional” carbon is, of course, called graphene.
In the many decades that followed– more than a century’s worth of decades– our understanding of graphite oxide evolved. We now understand that graphene oxide is a byproduct of the creation of graphite oxide. And industry has come to embrace graphene oxide as a versatile and incredibly useful nanomaterial.
Graphene Oxide: Most Common Uses
Graphene oxide serves a number of the same industries that use graphene. However, GO has its own unique properties and uses in those fields. Read on to learn graphene oxide’s special place in many industries.
- Conductive transparent coatings: Due to its thinness, transparency, and conductivity, graphene oxide can be used to conduct heat and electricity on the surface of devices that need to receive or emit light freely. Graphene coatings are used on digital displays, solar panels, and luminescent light sources.
- Flexible electronics: Graphene oxide is not quite as strong of a conductor as graphene. However, it can be used to form more durable membranes than graphene itself (GO is about 100 times easier to bend than graphene!). As such, GO is especially useful as a conductor in flexible electronics, such as implanted medical devices, electronics attached to moving printing heads, flexible LCD screens, etc….
- Water electrolysis: This is another instance where graphene oxide has an edge over graphene. While both graphene and GO are highly conductive, only GO is water-soluble. Once it’s dissolved in water, graphene oxide’s conductive properties can be used to facilitate electrolysis, which splits water into hydrogen and oxygen, allowing those elements to be filtered and used separately.
- Water filtration and purification: While graphene is used in sand filtration systems, graphene oxide, with its greater flexibility, can be used to enhance durable, sturdy water filtration membranes. GO is used in water filtration and desalination membranes in order to boost their efficiency and life cycle. This greatly reduces the cost of desalination and filtration. Flexible GO-enhanced sponges can also be used to absorb pollutants in water.
- Medicine: Graphene oxide has a number of medical applications. Due to its solubility and broad, flat surface area, GO is often used as a drug delivery agent. GO can also be used at the site of a cancerous growth to help conduct cancer-killing radiation.
- Biology: Here again, graphene oxide’s solubility comes in handy. GO can be bonded with other biocompatible chemicals to act as a biosensor, detecting and reacting to specific kinds of biological agents.
As you can see, graphene oxide is not interchangeable with graphene itself, but can complement it nicely in some industries. In other cases, the applications of GO are completely unique. Similarly, carbon nanotubes (CNT), which are made of graphene, have a number of their own unique properties and uses. Read our article on CNT next.
And be sure to check out the online ChemCeed catalog, where you can request a quote for graphene oxide, graphene, or CNT.