MIT developing platinum replacement
Fears of a looming crunch in platinum supply, driven mainly by a four-month-long ongoing strike at the world’s top producers of the metal in South Africa, may be about to fade.
MIT graduate student Sean Hunt, postdoc Tarit Nimmandwudipong, and Yuriy Román, an assistant professor of chemical engineering, are working on a new process to replace platinum-group metals (PGMs) with more widely available elements in renewable energy technologies.
In a paper published last week in the journal Angewandte Chemie, the team explains their proposed new method for synthesizing alternative catalysts.
“Because the PGMs tend to be the most active and stable catalysts in virtually all relevant thermal and electrocatalytic processes, our research sought to answer an exciting question,” they say. “Rather than finding new materials to replace PGMs in specific reactions, is it possible to modify the electron density of earth-abundant early transition metals [groups IV to VI on the periodic table] to catalytically mimic the PGMs?”
As a way to simplify their idea, the scientists use tungsten as an example. The element, with six valence electrons, they say, can be electronically modified to mimic platinum, which has 10 valence electrons, by reacting it with carbon (four valence electrons) to give the ceramic material tungsten carbide (WC).
Numerous studies have shown that WC is indeed platinum-like, and able to catalyze important thermo- and electrocatalytic reactions that tungsten metal cannot — such as biomass conversion, hydrogen evolution, oxygen reduction, and alcohol electro-oxidation.
They highlight that tungsten is three times more abundant than platinum in the Earth’s crust, making it a viable material for a global renewable-energy economy.
"While our research focuses mainly on the sustainable replacement of PGMs in thermal and electrocatalytic applications, we also anticipate broader impacts of our new TMC and TMN technologies outside catalysis,” says Román in a news release published by the MIT.
Stockpiling, recycling and long production times have prevented the prolonged South African platinum strike from causing a spike in global prices, but analysts warn volatility is coming, with consequences for the auto industry and other sectors.
The African nation accounts for 80% of the world's platinum supply and nearly a third of the world's palladium.
The longest and costlier strike ever by about 80,000 workers has halted nearly 40% of global platinum production at the top three producers – Anglo American Platinum (LON:AAL), Impala Platinum (JSE:IMP) and Lonmin (LON:LMI). Further, the strike has also resulted in a supply crunch for palladium, which prices hit a three-year high last week.