Clean energy on the cheap

A team from UC Berkeley and the US DoE may have overcome one of the biggest barriers to hydrogen power: the cost of platinum and other catalysts needed to extract it from water.

The primary hindrance to hydrogen's rise through the ranks of renewable energy sources has been the cost of producing it. To date, the process has been footbound by its dependence on that costliest of metals, platinum.

But researchers from UC Berkeley and the US Energy Department's Lawrence Berkeley National Laboratory appear to have come up with an inexpensive metal catalyst capable of extracting hydrogen from pH neutral water -- even if it's dirty or saline.

In late April, the team went to press in the journal Nature with an announcement of its success with the new catalyst, based on a molybdenum-oxo metal complex coming in about 98 percent cheaper than platinum.

"In addition, our catalyst does not require organic additives, and can operate in neutral water, even if it is dirty, and can operate in sea water, the most abundant source of hydrogen on earth and a natural electrolyte," team member Hemamala Karunadasa told the journal. "These qualities make our catalyst ideal for renewable energy and sustainable chemistry."

Hydrogen has long been the holy grail to the renewable energy sector for its ability to bridge the gap between internal combustion engines (as used by BMW in its experimental Hydrogen 7, pictured) and electricity generation via fuel cells such as those used in Honda's FCX and Mercedes-Benz's B-Class based F-Cell, both currently involved in experimental fleet testing. Either way, the volatile element's only exhaust emission is water vapour.

But the only affordable way to procure it at the moment is from natural gas -- which, being a fossil fuel, renders the enterprise largely futile by filling the atmosphere with CO2 in its extraction from the earth.

The key lies in the electrolysis of water -- the use of electricity to crack molecules of water open into their hydrogen and oxygen components. It's clean, it's sustainable, and to date it's been very costly because the most viable water-splitting catalyst is platinum, which currently sells for about US$2000 an ounce.

In addition to the new catalyst -- known as (PY5Me2)Mo-oxo -- the team is continuing its investigations into other, similar metal complexes for their catalytic capacity, both electrical and light-driven.

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