Published on January 14th, 2014 | by Tina Casey8
For Hydrogen Fuel Cells, Blue Is The New Green
A team of researchers at Argonne National Laboratory has figured out an efficient way to split hydrogen gas from water, using a low cost cobalt-based catalyst instead of pricey platinum. Hmmm, well, we were just wondering when hydrogen fuel cell electric vehicles would start nudging ahead of plug-in EVs in the race for market share, and guess what: that’s not going to happen real soon, but the Argonne breakthrough demonstrates that it could happen sooner rather than later.
While the media spotlight has been turned on plug-in electric vehicles for several years now (Tesla, much?), EVs powered by hydrogen fuel cells have been lingering in the shadows. That could change as the cost of fuel cells, and their fuel, trends steadily downwards.
Why We Can’t Have Cheap Hydrogen (For Now)
Hydrogen is an ideal fuel for a massive market like EVs, because it is everywhere – in water. The problem is getting into usable form, which requires enormous amounts of energy.
The sun could provide that energy on the cheap, without adding more carbon burden to the environment, in a photochemical process that mimics the steps of natural photosynthesis (see Daniel Nocera’s “artificial leaf” for more on that).
Between the sun and the water, though, there has to be a catalyst, so the search has been on for a low cost catalyst that can drive the photosynthetic reaction efficiently.
The National Institute of Standards and Technology (NIST) has come up with one promising way to drive down costs, which is to cut down on the amount of platinum needed for an efficient reaction.
The Argonne fuel cell approach is entirely different approach, eliminating platinum completely in favor of a cobalt-containing compound.
The Cobalt Road To Low Cost Hydrogen
Cobalt is a far less efficient catalyst than platinum but it is also far cheaper, hence the attraction to researchers.
Argonne writer Jared Sagoff notes that cobalt has already been explored as a catalyst, but until now the efficiency angle has been a hard nut to crack.
The research team at Argonne achieved their breakthrough by identifying a new way to link the catalyst to chromophores, which are organic light-sensitive molecules.
In a typical cobalt catalyst, the chromophore is connected directly to the cobalt atom within a compound, but that leads to a relatively unstable form of hydrogen generation and the process eventually breaks down.
That’s because a lot of the stimulated electrons shift from an excited state to a ground state before the energy transfer occurs.
The Argonne researchers tried another formation, connecting the chromophore to part of the organic ring around the cobalt atom. There is still some loss of state, but that reaction sustained much longer.
That’s just one avenue of exploration, by the way. Over at Pacific National Laboratory, researchers are also experimenting with a low cost nickel catalyst and a team of researchers in Australia is developing a plastic film catalyst that could strip hydrogen from seawater.
Along an entirely different track, Lawrence Livermore Laboratory is working with the company Chemergy on a thermochemical-based system for squeezing hydrogen out of municipal wastewater.
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