More uses for gold. This looks promising, as platinum and rhodium are 2x to 8x as expensive as gold.

http://www.nanostellar.com/Reports/RichesOfGoldCatalysis.pdf

For investors in platinum, palladium ($400/oz.) is increasingly being used as a substitute, which could damped demand for platinum. 87% of rhodium is also used in autocatalysts, so increasing use of gold could hammer rhodium price. see http://www.nature.com/news/2007/071114/full/450334a.html.

Also, if there is an oil crunch, demand for platinum and rhodium autocatalysts would evaporate.

Gold catalysis is EXTREMELY promising. There is a huge amount of reserach into gold catalysis at present becasue it has the potential to catalyse certain reactions with a much lower environmental overhead than conventional catalysts and is thus seen as 'green'.