Geologists at Stanford University made a diamond from oil. It sounds like alchemy, but with the right balance of substance, pressure and temperature, you can get pure diamond without the use of any catalysts. This is written in the journal Science Advances.
A new study by Stanford University and the SLAC National Accelerator Laboratory shows how, with careful adjustment of physical parameters, diamonds can be produced from hydrogen and carbon molecules found in crude oil and natural gas.
Scientists have synthesized diamonds from other materials for 60 years, but conversion usually requires an excessive amount of energy, time, or the addition of a catalyst, often a metal, which tends to lower the quality of the final product.
“But we wanted to create such a clean system in which only one substance is converted into pure diamond without the use of any catalyst”, says the lead author of the study, Suljie Park.
Such a transformation can be applied not only for the manufacture of jewelry. The physical properties of diamond — extreme hardness, optical transparency, chemical stability, and high thermal conductivity — make it a valuable material for medicine, industry, quantum computing technologies, and biological probing.
Natural diamonds crystallize from carbon at a depth of hundreds of kilometers from the surface of the Earth, where the temperature reaches several thousand degrees. Most of the natural diamonds discovered to date, soared as a result of volcanic eruptions millions of years ago, taking with them ancient minerals from the depths of the Earth.
To synthesize diamonds, the research team began with three types of powder extracted from the surface of oil tankers. “A small amount of powder is needed for the experiment,” said Mao. We used a needle to pick up a little powder under the microscope for our experiments”.
At first glance, the slightly sticky, odorless powders resemble rock salt. But with a microscope, one can distinguish atoms located in the same spatial pattern as the atoms that make up a diamond crystal. In fact, this is the same as cutting a complex diamond lattice into smaller blocks consisting of one, two or three cells.
Unlike diamond, which is pure carbon, powders known as diamondoids also contain hydrogen.
“Using these building blocks”, says Mao, “you can quickly and easily produce diamonds, and you can also learn more about this process than if you simply simulated the high pressure and high temperature found in that part of the Earth where diamond is formed naturally”.
For their experiment, the researchers loaded diamondoids into a pressure chamber the size of a plum called a cell with a diamond anvil, which presses the powder between two polished diamonds. With a simple manual rotation of the screw, the device can create pressure existing in the center of the earth.
Scientists then heated the samples with a laser, examined the results using a set of tests, and ran computer models to explain how the conversion occurs. They found that a three-component diamondoid, called triamantane, could be reorganized into a diamond with surprisingly low energy.
At 900 K, which is approximately 627°C, and 20 GPa, that is, a pressure hundreds of thousands of times higher than the Earth’s atmosphere, the carbon atoms of the triamantane equalize, and hydrogen dissipates or decays. The conversion takes place in a split second. The small size of the sample inside the cell with a diamond anvil makes this approach impractical for industrial synthesis, but it gives key knowledge about the production of diamonds.