Reducing Carbon Dioxide Using A Catalyst

Atmospheric CO₂ isn't especially useful by itself; among other things, it's implicated as a greenhouse gas. Plants, of course, convert CO₂ and sunlight into sugars and/or cellulose, according to the equasion

6CO₂ + 6H₂O + energy -> 6O₂ + C₆H₁₂O₆

The processes of photosynthesis are but little understood, though progress seems to have sped up in recent years. This three-year-old PowerPoint slideshow from Robert M. Granger, II, Ph.D of Sweet Briar College in Virginia, and this later one by Ana Ciric dated October 30, 2004, show remarkable progress in this field. Using a platinum-based catalyst, the team was able to convert raw CO₂ to various hydrocarbon chains (benzenes and simple sugars). If this can be made to work on a large scale -- and without reading anything more complicated than the slideshows, it's hard to tell -- this could have huge implications for global warming. Unfortunately, economic application is likely going to be limited unless another catalyst besides platinum ends up being used here.

Not knowing anything about chemistry, but why is it that platinum is always so critical to industrial catalytic reactions?