When it comes to metal catalysts, the platinum standard is, well, platinum! However, at about $2,000 an ounce, platinum is more expensive than gold. The high cost of the raw material presents major challenges for the future wide scale use of platinum in fuel cells. Research at the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) suggests that one possible way to meet these challenges is to think small really small.
A study led by Gabor Somorjai and Miquel Salmeron of Berkeley Lab's Materials Sciences Division showed that under high pressure, comparable to the pressures at which many industrial technologies operate, nanoparticle clusters of platinum potentially can out-perform the single crystals of platinum now used in fuel cells and catalytic converters.
"We've discovered that the presence of carbon monoxide molecules can reversibly alter the catalytic surfaces of platinum single crystals, supposedly the most thermodynamically stable configuration for a platinum catalyst," said Somorjai, one of the world's foremost experts on surface chemistry and catalysis. "This indicates that under high-pressure conditions, single crystals of platinum are not as stable as nanoclusters, which actually become more stabilized as carbon monoxide molecules are co-adsorbed together with platinum atoms."
"Our results also demonstrate that the limitations of traditional surface science techniques can be overcome with the use of techniques that operate under realistic conditions, says Salmeron, a leading authority on surface imaging and developer of the in situ imaging and spectroscopic techniques used in this study. He is also the director of Berkeley Lab's Materials Sciences Division.
In this study, single crystal platinum surfaces were examined under high-pressure. The surfaces were structured as a series of flat terraces about six atoms wide separated by atomic steps. Such structural feature are common
|Contact: Lynn Yarris|
DOE/Lawrence Berkeley National Laboratory