In an ambition to address the challenges of hydrogen, specifically the reliance on fossil fuels and expensive precious metals like platinum, scientists developed a method to convert metal waste into a catalyst that produces hydrogen from water.
A team of researchers from the University of Nottingham’s School of Chemistry and Faculty of Engineering led by Dr. Jesum Alves Fernandes proposed repurposing metal waste into an efficient catalyst in hydrogen production.
This method is also cost-efficient in addition to being sustainable.
This leap in technology presents new opportunities to allow the sustainable functioning of power vehicles via the use of clean fuel. Hydrogen fuel can be employed to generate heat for such applications.
The researchers say that water vapor is the only byproduct of hydrogen combustion.
Since hydrogen production conventionally relies on fossil fuel feedstock, this technology presents “the most promising green pathways for hydrogen production” via electrolysis of water.
Electrocatalyst splits H2O into H2 and O2
Scientists 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.”
Usually, the process of electrolyzing water for hydrogen production relies on platinum, which is a rare and expensive metal.
The limited global supply of such a precious metal is making the traditional approach unsustainable, calling for an imminent need for an alternative.
Now, metal waste has become a cost-effective and abundant electrocatalyst material, making hydrogen production more viable and scalable.
Fernandes emphasized that industries in the UK solely 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,” he said.
“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.”
Rain of platinum atoms on a surface
Magnetron was utilized to deposit platinum atoms onto the surface of the metal waste–swarf.
This process creates a “rain” of platinum atoms on the surface which then assemble into nanoparticles, fitting perfectly into the tiny grooves of the surface.
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 to state-of-the-art commercial catalysts.”
Researchers spread just 28 micrograms of the precious metal over 1 cm² of the swarf. They successfully devised a laboratory-scale electrolyzer.
Thangamuthu stated that the electrolyzer “operates with 100 percent efficiency and produces 0.5 liters of hydrogen gas per minute just from a single piece of swarf.”
The researchers are collaborating with AqSorption Ltd, a Nottingham-based company specializing in electrolyzer design and fabrication, to scale up their technology.
Professor Andrei Khlobystov, School of Chemistry, University of Nottingham, said that the electrocatalysts made from swarf have the potential to greatly impact the economy.
The unique technology involving atom-by-atom growth of platinum particles on nanotextured surfaces 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,” Khlobystov noted.
The study was published earlier today in the Journal of Material Chemistry A of the Royal Society of Chemistry.
