Curiosity and perseverance combine to unmask the mystery metal at the heart of a green-fuel-forming reaction.
In the kitchen, microwaves and metals do not mix. But in the lab – with careful handling – the results can be spectacular. Using an under-appreciated microwave-based method called electron paramagnetic resonance (EPR) spectroscopy, KAUST research scientist Jeremy Bau from Magnus Rueping’s research group has captured an elusive molybdenum-hydrogen bond.
The finding settles a nearly two-decade-long debate on molybdenum’s role in an electrocatalyst that splits water molecules to produce clean hydrogen fuel. “The overall goal is to provide a strong rationale for why we can replace expensive platinum catalysts with molybdenum, a relatively common industrial metal,” says Bau. “Economically and environmentally, this would be a huge upgrade.”
Although molybdenum-containing electrocatalysts have shown promise, molybdenum’s role in the reaction had remained an enigma, limiting efforts to design improved catalysts.
One possibility was that molybdenum in the +3 oxidation state was the catalytically active species. “I’d been reading about EPR as a possible way to detect this oxidation state,” Bau says. EPR is rarely used in modern electrocatalysis research, but Bau suspected it could be the right technique for the task. “EPR allows you to detect elements that are paramagnetic, where you don’t have a fully paired electron set, such as Molybdenum 3+,” he explains.
“I thought it was an interesting idea, and Jeremy’s combination of skills and enthusiasm were ideal for the project,” Rueping says.
Read more at KAUST Insight.
