The researchers from Nottingham University's School of Chemistry and Faculty of Engineering have found that the surface of swarf is textured with nanoscale steps and grooves that can anchor atoms of platinum or cobalt, leading to an efficient electrocatalyst that can split water into hydrogen and oxygen. The research has been published in the Journal of Material Chemistry A of the Royal Society of Chemistry.
Electrolysis of water is a promising green method for producing hydrogen, but this process requires rare and expensive elements like platinum to catalyse the water splitting. With the limited global supply and increasing prices of precious metals, there is an urgent need for alternative electrocatalyst materials to produce hydrogen from water.
In a statement, research lead Dr Jesum Alves Fernandes, School of Chemistry, Nottingham University, said: “By using a scanning electron microscope, we were able to inspect the seemingly smooth surfaces of the stainless steel, titanium, or nickel alloy swarf. To our astonishment, we discovered that the surfaces had grooves and ridges that were only tens of nanometres wide. We realised that this nanotextured surface could present a unique opportunity for the fabrication of electrocatalysts.”
The researchers used magnetron sputtering deposit platinum atoms on the swarf's surface. These platinum atoms then come together into nanoparticles that occupy the nanoscale grooves.
Dr Madasamy Thangamuthu, a postdoctoral researcher at Nottingham University who was responsible for the analysis of the structure and electrocatalytic activity of the new materials, said: “It is remarkable that we are able to produce hydrogen from water using only a tenth of the amount of platinum loading compared to state-of-the-art commercial catalysts. By spreading just 28 micrograms of the precious metal over 1cm² of the swarf, we were able to create a laboratory-scale electrolyser that operates with 100 per cent efficiency and produces 0.5 litres of hydrogen gas per minute just from a single piece of swarf.”
The group is partnering with AqSorption Ltd, a Nottingham-based company specialising in electrolyser design and fabrication to scale up their technology.
Professor Andrei Khlobystov, School of Chemistry, Nottingham University , said: “The electrocatalysts made from swarf have the potential to greatly impact the economy. Our unique technology developed at Nottingham, which involves atom-by-atom growth of platinum particles on nanotextured surfaces, has solved two major challenges. Firstly, it enables the production of green hydrogen using the least amount of precious metal possible, and secondly, it upcycles metal waste from the aerospace industry, all in a single process.”
This work was funded by the EPSRC Programme Grant ‘Metal atoms on surfaces and interfaces (MASI) for sustainable future’.
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