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Grooves on swarf surface to help with hydrogen generation

Nicola Brittain

Researchers turn metal waste into a catalyst for hydrogen.

Scientists have found a way to transform metal waste into a highly efficient catalyst to make hydrogen from water, a discovery that could make hydrogen production more sustainable.

A team of researchers from the University of Nottingham’s School of Chemistry and Faculty of Engineering have found that the surface of swarf, a byproduct of the metal machining industry, is textured with tiny steps and grooves on a nanoscale level. These textures can anchor atoms of platinum or cobalt, leading to an efficient electrocatalyst that can split water into hydrogen and oxygen.

Hydrogen is a clean fuel that can be used to generate heat or power vehicles, and the only by product of its combustion is water vapour. However, most hydrogen production methods rely on fossil fuel feedstock. Electrolysis of water is one of the most promising green pathways for hydrogen production, as it only requires water and electricity.

Challenge of water electrolysis

The industry is facing a challenge with water electrolysis, as this process requires rare and expensive elements like platinum to catalyse the water splitting. With the limited global supply and increasing price of precious metals, there is an urgent need for alternative electrocatalyst materials to produce hydrogen from water.

Dr Jesum Alves Fernandes, from the school of chemistry, University of Nottingham, who led the research team, said: “Industries in the UK alone generate millions of tons of metal waste annually. 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 realized that this nanotextured surface could present a unique opportunity for the fabrication of electrocatalysts.”

The researchers used magnetron sputtering to create a platinum atom ‘rain’ on the swarf’s surface. These platinum atoms then come together into nanoparticles that fit snugly into the nanoscale grooves.

Dr Madasamy Thangamuthu, a postdoctoral researcher at the University of Nottingham who was responsible for the analysis of the structure and electrocatalytic activity of the new materials, says: “It is remarkable that we are able to produce hydrogen from water using only a tenth of the amount of platinum loading compared with state-of-the-art commercial catalysts. By spreading just 28 micrograms of the precious metal over 1 cm² of the swarf, we were able to create a laboratory-scale electrolyser operating with 100% efficiency and producing 0.5 litres of hydrogen gas per minute just from a single piece of swarf.”

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