Hydrogen is considered an almost ideal fuel because when burned it does not emit harmful greenhouse gases such as CO2 - only water vapor. The era of clean fuel, however, has not yet arrived - it is too expensive to produce hydrogen. One of the reasons is that the process uses noble metal catalysts.
Scientists at Tomsk Polytechnic University (TPU) have found a more affordable alternative to platinum group metals and developed a technology for producing a promising material - cubic tungsten carbide. How the discovery of Russian researchers will bring closer the widespread use of hydrogen fuel - under the cut.
Why hydrogen?
The demand for hydrogen is growing, and the volume of its use doubles every 15 years. This chemical element is widely used in the oil industry.
In addition, hydrogen plays a key role in the so-called decarbonization of the economy, which means avoiding the use of hydrocarbons. As a fuel, it is one of the most harmless alternatives. By estimates BloombergNEF (BNEF), so-called "green" hydrogen obtained by electrolysis can reduce the global emission of greenhouse gases to 34% of the 2050 year.
Today, the volume of the hydrogen fuel market is estimated at $ 700 billion. In all the strategic documents of the European Union, adopted recently, hydrogen is named the main driver of growth to overcome the economic crisis caused by COVID-19.
Production difficulties
Hydrogen is practically not found on Earth in its pure form; the element is extracted from other compounds as a result of chemical reactions. As a rule, this is a production that is economically unprofitable or it is difficult to put it on industrial rails. Scientists are studying various ways to make hydrogen production cheaper and easier. After all, this directly affects how quickly the world can switch to greener fuels.
BNEF experts predict that even before 2030, "green" hydrogen will cost just over $ 2 / kg and will compete with coal and natural gas in industry, for example, in steel production. And by 2050, the chemical element will be able to compete in price with the cheapest coal, while not producing a single gram of CO2.
The prospects are good. For example, a year ago, the German oil company Shell began building one of the world's largest hydrogen production plants by electrolysis. It is planned to start operating by the end of the year and will be able to produce up to 1,300 tons of hydrogen annually.
Cheaper catalyst
Typically, hydrogen electrolysis uses catalysts made of platinum group metals - platinum, iridium, ruthenium and their derivatives. All of them are classified as precious metals and are very expensive.
A cheaper analogue is cubic tungsten carbide. The conditions for its production are not simple: synthesis requires a temperature of 3000 ° C and very rapid cooling. But the scientists of the Tomsk Polytechnic University managed to develop a device that allows the production of this material with a high percentage of purity (up to 95%).
Installation - coaxial magnetoplasma accelerator. It achieves high temperatures and ultra-fast cooling with the help of plasma jets. Their speed is over 3 km / s, and the reaction itself takes less than 1 ms. Available and relatively cheap powders of tungsten and carbon black are placed in the accelerator. In the working chamber of the device, the initial powders are transformed into cubic tungsten carbide during the plasma-chemical reaction. The scientists described the results of the experiments in the scientific journal Journal of Alloys and Compounds .
“The nanoparticles of cubic tungsten carbide obtained during the reaction are successfully used in the reaction of obtaining hydrogen from water. This will allow minimizing the use of rare and expensive precious metals of the platinum group, ” says Ivan Shanenkov, associate professor of the TPU Department of Electricity and Electrical Engineering .
What's next
TPU scientists have confirmed the promising nature of the material together with Chinese researchers from Jilin University and Qingdao University. In the future, scientists plan to increase the catalytic activity of the material and completely abandon the use of expensive noble metals in the electrocatalysis of hydrogen from water.
