Noble metals such as osmium and ruthenium, elements virtually as rare as gold and platinum, play a crucial role in illuminating technology screens like mobile phones and laptops, as well as converting solar energy into fuels.
Now, chemists at Basel University in Switzerland have succeeded in replacing these expensive metals with the significantly cheaper metal, chromium.
In the academic journal, Nature Chemistry, scientists reported that the luminescent properties of chromium are comparable to both osmium and ruthenium. However, chromium happens to be approximately 20,000 times more abundant in the earth’s crust.
Chromium, a lustrous silver-grey metal, is frequently used in everyday items like kitchen appliances and motorcycles. It is responsible for items that are labelled “stainless steel.” The brittle metal has attractive anticorrosive properties and adding it to steel ensures resistance to degradation and tarnishing.
Additionally, adding a layer of chromium to another metal creates what is commonly known as “chrome plating” or “chrome.”
Chrome can reflect as much as 70% of the visible light spectrum, as well as 90% of infrared radiation. Scientists have found that when illuminated by an infrared lamp, chromium compounds stored energy for later use, much like photosynthesis in plants.
Professor and research lead of University of Basel’s chemistry department, Oliver Wenger, said, “Because of this, there’s also the potential to use our new materials in artificial photosynthesis to produce solar fuels.”
Subsequently, the new discovery could boost efforts in the clean energy transition by providing technology manufacturers with alternative components.
To test the chromium atoms as a way of converting energy, Wenger’s team built the atoms into a molecular framework along with carbon, nitrogen, and hydrogen. They packaged the chromium into a tight framework to avoid energy loss when the molecules vibrated, and to ensure that they worked optimally.
According to The Independent, scientists have advised that this framework is more complex and therefore more difficult to implement than what is required for osmium and ruthenium, but they believe this hurdle could be overcome with further research.
Previous research into noble metal alternatives has explored the potential of using iron and copper, to some success, however, chromium has (initially) appeared to perform better than both options. That said, Wenger commented, “It seems unclear which metal will ultimately win the race when it comes to future applications in luminescent materials and artificial photosynthesis.”
The researchers aim to develop their materials on a larger scale to allow for wider testing of potential applications in the near future. By making further improvements, they hope to achieve light emission of a wide array of colours. Optimizing chromium’s catalytic attributes could bring abought benefits like achieving artificial photosynthesis — converting sunlight into chemical energy for storage.
